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Leon J. Spicer - One of the best experts on this subject based on the ideXlab platform.
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Effects of Estradiol on Bovine Thecal Cell Function In Vitro: Dependence on Insulin and Gonadotropins
Journal of dairy science, 2005Co-Authors: Leon J. SpicerAbstract:Abstract The objective of this study was to evaluate the influence of estradiol (E2) on proliferation and steroid production by Thecal Cells obtained from large (≥8mm) follicles of cattle. Five experiments evaluated the effect of various doses of E2 during a 2-d exposure in serum-free medium on hormone-induced steroidogenesis and cell proliferation. In LH-treated Thecal Cells of experiment 1, 300ng/mL of E2 decreased progesterone production by 30% and increased androstenedione production to 5.8-fold of controls. In the absence of LH, both 3 and 300ng/mL of E2 increased progesterone production. In experiment 2, in the presence of insulin and LH, 3, 30, and 300ng/mL of E2 decreased progesterone production (by 17 to 36%), whereas 3ng/mL of E2 decreased and 300ng/mL of E2 increased androstenedione production. Doses of LH (3 to 30ng/mL) tested in experiment 3 increased (to as much as 3.7-fold) progesterone production by Thecal Cells and E2 attenuated this stimulatory effect by 40%. In contrast, E2 amplified the stimulatory effect of LH on androstenedione production in experiment 3. In experiment 4, E2 (300ng/mL) decreased IGF-I- and insulin-induced Thecal cell progesterone production by 70 to 77%, whereas E2 increased basal, IGF-I, and insulin-induced androstenedione production. In experiment 5, in the presence of insulin, 10 to 1000ng/mL of E2 had no effect on [ 125 I]-IGF-I binding to Thecal Cells, whereas 10 and 100ng/mL of E2 increased and 1000ng/mL of E2 decreased progesterone production by Thecal Cells. Estradiol had no consistent effect on Thecal cell numbers among the 5 experiments. These results support the hypothesis that E2 may act as a paracrine factor to directly regulate hormone-induced steroid production by Thecal Cells without affecting cell numbers or numbers of insulin-like growth factor type I receptors.
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Insulin-like growth factor-II stimulates steroidogenesis in cultured bovine Thecal Cells.
Molecular and Cellular Endocrinology, 2004Co-Authors: Leon J. Spicer, J.l. Voge, D. T. AllenAbstract:Abstract The objective of the present study was to determine the effects of insulin-like growth factor-II (IGF-II) on luteinizing hormone (LH)-induced progesterone and androstenedione production by bovine Thecal Cells and compare it to that of insulin and IGF-I. Cells from large (>7.9 mm) bovine follicles were collected and cultured for 2 days in the presence of 10% fetal calf serum. Then Cells were cultured for an additional 1 or 2 days in serum-free medium with various doses of recombinant human IGF-II, bovine LH (30 ng/ml), IGF-I, and(or) insulin. Cell numbers were determined at the end of treatments via Coulter counting and used to correct steroid production data. In the presence of LH, 1-day treatment with 3–300 ng/ml of IGF-II had no significant effect on progesterone or androstenedione production, whereas 2-day treatment with 30, 100 and 300 ng/ml of IGF-II increased ( P P P 125 I-IGF-II existed in Thecal Cells with a 25 ng/well of IGF-II causing 50% inhibition of binding. IGF-I cross-reactivity with 125 I-IGF-II receptors averaged 3% whereas cross-reactivity of IGF-II with 125 I-IGF-I receptors averaged 114%. These results indicate that the stimulatory effects of IGF-II on Thecal cell steroidogenesis is mediated by IGF type I receptors and thus IGF-II, like IGF-I, may play a significant role in Thecal cell steroidogenesis during follicular development.
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Estradiol and luteinizing hormone regulation of insulin-like growth factor binding protein production by bovine granulosa and Thecal Cells
Endocrine, 2002Co-Authors: Leon J. Spicer, Connie S ChamberlainAbstract:To determine the effects of estradiol and luteinizing hormone (LH) on insulin-like growth factor-binding protein (IGFBP) production by bovine granulosa and Thecal Cells, both cell types were collected and cultured in serum-free medium with various hormone treatments, arranged in three experiments. In Thecal Cells, insulin stimulated ( p 0.10) on IGFBP-3 and IGFBP-4 production; LH stimulated ( p 0.05) on IGFBP-4 and IGFBP-5. Estradiol had no effect ( p >0.10) on IGFBP-2, IGFBP-3, IGFBP-4, and IGFBP-5 production by Thecal Cells. Production of IGFBP-2/-5 by granulosa Cells from small follicles was inhibited ( p 0.10) insulin’s inhibitory effect on basal IGFBP-2/-5 production. Insulin, LH, and estradiol each inhibited IGFBP-4 production by small-follicle granulosa Cells, but their effects were not additive. IGFBP-3 was not produced by small-follicle granulosa Cells. In large-follicle granulosa Cells, insulin and LH inhibited ( p 0.10) on production of IGFBP-4, but estradiol and LH inhibited ( p
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Estradiol and luteinizing hormone regulation of insulin-like growth factor binding protein production by bovine granulosa and Thecal Cells.
Endocrine, 2002Co-Authors: Leon J. Spicer, Connie S ChamberlainAbstract:To determine the effects of estradiol and luteinizing hormone (LH) on insulin-like growth factor-binding protein (IGFBP) production by bovine granulosa and Thecal Cells, both cell types were collected and cultured in serum-free medium with various hormone treatments, arranged in three experiments. In Thecal Cells, insulin stimulated (p < 0.05) production of IGFBP-2 and IGFBP-5, but had no effect (p > 0.10) on IGFBP-3 and IGFBP-4 production; LH stimulated (p < 0.05) production of IGFBP-2 and IGFBP-3 but had no effect (p > 0.05) on IGFBP-4 and IGFBP-5. Estradiol had no effect (p > 0.10) on IGFBP-2, IGFBP-3, IGFBP-4, and IGFBP-5 production by Thecal Cells. Production of IGFBP-2/-5 by granulosa Cells from small follicles was inhibited (p < 0.05) by insulin, but estradiol and LH did not influence (p > 0.10) insulin's inhibitory effect on basal IGFBP-2/-5 production. Insulin, LH, and estradiol each inhibited IGFBP-4 production by small-follicle granulosa Cells, but their effects were not additive. IGFBP-3 was not produced by small-follicle granulosa Cells. In large-follicle granulosa Cells, insulin and LH inhibited (p < 0.05) production of IGFBP-2/-5 and IGFBP-3, whereas estradiol had no effect. Insulin alone had no effect (p > 0.10) on production of IGFBP-4, but estradiol and LH inhibited (p < 0.05) production by large-follicle granulosa Cells, and their effects were not additive. These results suggest that production of IGFBP-2, IGFBP-3, IGFBP-4, and IGFBP-5 by granulosa and Thecal Cells is differentially affected by hormonal stimuli.
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Hormonal control of ovarian cell production of insulin-like growth factor binding proteins
Molecular and cellular endocrinology, 2001Co-Authors: Connie S Chamberlain, Leon J. SpicerAbstract:To determine if the hormonal effects on insulin-like growth factor binding protein (IGFBP) production differed between granulosa and Thecal Cells, both cell types were collected and cultured in serum-free medium with various hormone treatments, arranged in three experiments. Following treatment, Cells were enumerated and media were collected, concentrated 10-fold and subjected to ligand blotting. Experiment 1 revealed that > or =1.5 x 10(5) viable Cells at plating were needed for maximal IGFBP production by granulosa and Thecal Cells. The major forms of IGFBPs produced were a 27-34-kDa IGFBP (IGFBP-2 and -5), and a 20-22-kDa IGFBP (IGFBP-4) by the granulosa Cells and a 40-44-kDa IGFBP (IGFBP-3), 34-kDa IGFBP (IGFBP-2), 27-29-kDa IGFBP (IGFBP-5) and a 20-22-kDa IGFBP (IGFBP-4) by the Thecal Cells. In Experiment 2A, insulin stimulated production of IGFBP-5 by Thecal Cells, and basic fibroblast growth factor (bFGF) inhibited the insulin-induced increase in IGFBP-5 production; epidermal growth factor (EGF) and luteinizing hormone were without effect. The small amounts of IGFBP-2 and -3 produced by Thecal Cells of Experiment 2A were not affected by treatment. Production of IGFBP-2/-5 by granulosa Cells in Experiment 2B was inhibited by insulin, with EGF and bFGF further enhancing insulin's inhibitory effect; follicle-stimulating hormone was without effect. In Experiment 3A, insulin enhanced production of IGFBP-5 by Thecal Cells whereas glucagon blocked insulin's stimulatory effect. In contrast, insulin or glucagon alone had no effect on production of the IGFBP-4 by Thecal Cells but when combined inhibited IGFBP-4 production. The small amounts of IGFBP-2 and -3 produced by Thecal Cells of Experiment 3A were not affected by treatment. In Experiment 3B, production of IGFBP-2/-5 by granulosa Cells was attenuated in the presence of cortisol with or without insulin and insulin plus glucagon; glucagon and cortisol decreased production of IGFBP-4 by granulosa Cells. These results suggest that production of IGFBP-2, -4, and -5 by granulosa and Thecal Cells are differentially affected by hormonal stimuli, and that IGFBP-3 is more consistently produced by Thecal Cells than granulosa Cells of cattle although its production was not hormonally regulated.
L J Spicer - One of the best experts on this subject based on the ideXlab platform.
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Insulin-like growth factor-II stimulates steroidogenesis in cultured bovine Thecal Cells.
Molecular and cellular endocrinology, 2004Co-Authors: L J Spicer, J.l. Voge, D. T. AllenAbstract:The objective of the present study was to determine the effects of insulin-like growth factor-II (IGF-II) on luteinizing hormone (LH)-induced progesterone and androstenedione production by bovine Thecal Cells and compare it to that of insulin and IGF-I. Cells from large (>7.9 mm) bovine follicles were collected and cultured for 2 days in the presence of 10% fetal calf serum. Then Cells were cultured for an additional 1 or 2 days in serum-free medium with various doses of recombinant human IGF-II, bovine LH (30 ng/ml), IGF-I, and(or) insulin. Cell numbers were determined at the end of treatments via Coulter counting and used to correct steroid production data. In the presence of LH, 1-day treatment with 3-300 ng/ml of IGF-II had no significant effect on progesterone or androstenedione production, whereas 2-day treatment with 30, 100 and 300 ng/ml of IGF-II increased (P < 0.05) both progesterone and androstenedione production by 2-3-fold. The estimated effective dose of IGF-II stimulating 50% of the maximal steroidogenic response was calculated to be 25 ng/ml. In the absence of LH, 2-day treatment of IGF-I or -II had no effect on Thecal androstenedione production but increased (P < 0.05) Thecal progesterone production. In the presence of LH, 100 ng/ml of IGF-I increased progesterone and androstenedione production to a greater degree than did 100 ng/ml of IGF-II. Maximal effects of IGF-I and insulin on Thecal steroidogenesis were similar and were not additive. Anti-IGF type I receptor antibodies attenuated (P < 0.05) the stimulatory effect of both IGF-I and IGF-II on Thecal cell steroidogenesis. Use of radioligand assays demonstrated that specific receptors for (125)I-IGF-II existed in Thecal Cells with a 25 ng/well of IGF-II causing 50% inhibition of binding. IGF-I cross-reactivity with (125)I-IGF-II receptors averaged 3% whereas cross-reactivity of IGF-II with (125)I-IGF-I receptors averaged 114%. These results indicate that the stimulatory effects of IGF-II on Thecal cell steroidogenesis is mediated by IGF type I receptors and thus IGF-II, like IGF-I, may play a significant role in Thecal cell steroidogenesis during follicular development.
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estradiol and luteinizing hormone regulation of insulin like growth factor binding protein production by bovine granulosa and Thecal Cells
Endocrine, 2002Co-Authors: L J Spicer, Connie S ChamberlainAbstract:To determine the effects of estradiol and luteinizing hormone (LH) on insulin-like growth factor-binding protein (IGFBP) production by bovine granulosa and Thecal Cells, both cell types were collected and cultured in serum-free medium with various hormone treatments, arranged in three experiments. In Thecal Cells, insulin stimulated (p 0.10) on IGFBP-3 and IGFBP-4 production; LH stimulated (p 0.05) on IGFBP-4 and IGFBP-5. Estradiol had no effect (p>0.10) on IGFBP-2, IGFBP-3, IGFBP-4, and IGFBP-5 production by Thecal Cells. Production of IGFBP-2/-5 by granulosa Cells from small follicles was inhibited (p 0.10) insulin’s inhibitory effect on basal IGFBP-2/-5 production. Insulin, LH, and estradiol each inhibited IGFBP-4 production by small-follicle granulosa Cells, but their effects were not additive. IGFBP-3 was not produced by small-follicle granulosa Cells. In large-follicle granulosa Cells, insulin and LH inhibited (p 0.10) on production of IGFBP-4, but estradiol and LH inhibited (p<0.05) production by large-follicle granulosa Cells, and their effects were not additive. These results suggest that production of IGFBP-2, IGFBP-3, IGFBP-4, and IGFBP-5 by granulosa and Thecal Cells is differentially affected by hormonal stimuli.
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Receptors for insulin-like growth factor-I and tumor necrosis factor-alpha are hormonally regulated in bovine granulosa and Thecal Cells.
Animal reproduction science, 2001Co-Authors: L J SpicerAbstract:Mastitis induces release of tumor necrosis factor-alpha (TNFalpha) and has been linked with reduced reproductive performance. To further elucidate the role and mechanism of action of TNFalpha on ovarian Cells, the effect of TNFalpha on insulin-like growth factor-I (IGF-I)-induced steroidogenesis and IGF-I binding sites in granulosa and Thecal Cells as well as the hormonal regulation of TNFalpha receptors were evaluated. Granulosa and Thecal Cells were obtained from small (1-5mm) and large (> or =8mm) bovine ovarian follicles, respectively, and cultured for 3-4 days. During the last 2 days of culture, Cells were treated with various hormones and steroid production and specific binding of 125I-IGF-I and 125I-TNFalpha was determined. Two-day treatment with 30 ng/ml of TNFalpha decreased (P
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effects of thyroid hormones on bovine granulosa and Thecal cell function in vitro dependence on insulin and gonadotropins
Journal of Dairy Science, 2001Co-Authors: L J Spicer, J Alonso, Connie S ChamberlainAbstract:The objective of this study was to evaluate the influence of thyroxine (T4) and triiodothryonine (T3) on steroid production by bovine granulosa and Thecal Cells. Granulosa and Thecal Cells were obtained from small (1 to 5 mm) and large (> or = 8 mm) follicles of cattle, respectively, and cultured for 4 d. We conducted six experiments to evaluate the effect of 2 d of exposure to various doses of T3 or T4. In insulin- or insulin plus FSH-treated granulosa Cells of experiment 1, 30 and 100 ng/ml of T4 had no effect on aromatase activity or progesterone production. In experiment 2, in the presence of insulin and FSH, 1 and 3 ng/ml of T3 weakly (<1.4-fold) increased aromatase activity of granulosa Cells but had no effect on progesterone production. Low doses of T4 (3 to 30 ng/ml) tested in experiment 3 had no effect on aromatase activity but increased (to as much as 1.4-fold) progesterone production by granulosa Cells. In experiment 4, T4 (30 ng/ml) increased (to 1.2-fold) progesterone production by granulosa Cells only in the presence of FSH and had no effect on aromatase activity. In Thecal Cells of experiment 5, in the presence of insulin and LH, 30 and 100 mg/ml of T4 increased androstenedione production to 2.3- and 2.8-fold, respectively; only 100 ng/ml of T4 was effective at stimulating progesterone production by Thecal Cells. In experiment 6, 1 ng/ml of T3 increased Thecal cell androstenedione production to 3.9-fold, whereas 3 ng/ml of T3 was without effect; progesterone production was not affected by T3. These results support the hypothesis that thyroid hormones may have direct stimulatory effects on ovarian function in cattle, acting at the level of granulosa and Thecal Cells.
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production of insulin like growth factor i by granulosa Cells but not Thecal Cells is hormonally responsive in cattle
Journal of Animal Science, 2000Co-Authors: L J Spicer, Connie S ChamberlainAbstract:To determine whether the hormonal regulation of IGF-I production differs between granulosa and Thecal Cells in cattle, granulosa and Thecal Cells from bovine follicles were collected, cultured for 2 d in medium containing 10% fetal calf serum, washed, and then treated for an additional 24 h in serum-free medium with various hormones. In Exp. 1, granulosa Cells were treated with 0 or 100 ng/mL of insulin and(or) 50 ng/mL of follicle-stimulating hormone (FSH), insulin plus 10 ng/mL of epidermal growth factor, or insulin plus 10 ng/mL of basic fibroblast growth factor. In Exp. 2, Thecal Cells were treated as described in Exp. 1 except that 100 ng/mL of luteinizing hormone (LH) was used instead of 50 ng/mL of FSH. In Exp. 3, granulosa and Thecal Cells were treated with 0 or 30 ng/mL of cortisol with or without 100 ng/mL of insulin, 300 pg/mL of glucagon, or glucagon plus insulin. In Exp. 4, granulosa and Thecal Cells were treated with 0 or 300 ng/mL of estradiol with or without 100 ng/mL of insulin and(or) 100 ng/mL of LH. At the end of treatment, medium was collected, concentrated with Centricon-3 concentrators, and assayed for IGF-I by radioimmunoassay. Cell numbers were determined by Coulter counting at the end of culture. Thecal Cells produced low amounts of IGFI (0.48 +/- 0.04, 0.63 +/- 0.03, and 0.82 +/- 0.03 ng per 100,000 Cells per 24 h in Exp. 2, 3, and 4, respectively), and this production was not influenced (P > 0.05) by the various treatments. In contrast, IGF-I production by granulosa Cells (2.0 to 6.2 ng per 100,000 Cells per 24 h) was influenced by treatment in Exp. 1, 3, and 4 and was greater than IGF-I production by Thecal Cells (Exp. 2, 3, and 4). Alone, insulin, FSH, LH, and cortisol (but not estradiol) each decreased (P 0.10) on IGF-I production in the absence or presence of insulin. In the presence of insulin, epidermal growth factor, basic fibroblast growth factor, and estradiol decreased (P < 0.05) IGF-I production below that observed for insulin alone. These results indicate that, during follicular development in cattle, changes in intrafollicular levels of IGF-I may be due to hormonally-induced changes in granulosa-cell, but not Thecal-cell, IGF-I production.
R E Stewart - One of the best experts on this subject based on the ideXlab platform.
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Insulin-like growth factor-binding protein-2 and -3: their biological effects in bovine Thecal Cells.
Biology of reproduction, 1997Co-Authors: Leon J. Spicer, R E Stewart, P Alvarez, C. C. Francisco, B E KeeferAbstract:This study was aimed at testing the hypothesis that the insulin-like growth factor-binding proteins (IGFBP)-2 and -3 can modulate the hormone-dependent differentiation of Thecal Cells in vitro. Thecal Cells from large (> or = 8 mm) follicles were collected from cattle, cultured for 2 days in medium containing 10% fetal calf serum, washed, and then treated for an additional 2 days in serum-free medium with bovine LH (100 ng/ml), recombinant human insulin-like growth factor (IGF)-I (0 or 30 ng/ml), recombinant human IGFBP-2 (0, 200, or 400 ng/ml; i.e., 0, 6.5, or 12.9 nM), or recombinant human IGFBP-3 (0, 200, or 400 ng/ml; i.e., 0, 4.3, or 8.5 nM). IGFBP-2 (200 and 400 ng/ml) inhibited (p < 0.05) IGF-I-induced androstenedione production by 18-30% but did not influence (p > 0.10) progesterone production or Thecal cell proliferation in the presence of LH and/or IGF-I. In contrast, IGFBP-3 (200 ng/ml) inhibited the IGF-I-induced increase in Thecal cell numbers by 76%, and Thecal cell progesterone and androstenedione production by 52% and 89%, respectively. A higher dose of IGF-I (i.e., 100 ng/ml) overcame the inhibitory effects of IGFBP-3 on IGF-I-induced cell proliferation and on progesterone and androstenedione production by Thecal Cells. As with IGFBP-2, IGFBP-3 had no effect (p > 0.10) on LH-induced progesterone or androstenedione production by Thecal Cells in the absence of IGF-I. Both IGFBP-2 and IGFBP-3 directly inhibited [125I]IGF-I and -II binding to Thecal Cells; IGFBP-2 was a weaker inhibitor of Thecal [125I]IGF-I and -II binding than IGFBP-3. These results indicate that IGFBP-3 has a more pronounced inhibitory effect than IGFBP-2 on IGF-I action in cultured bovine Thecal Cells. Thus, IGFBP-3 may play a more significant role than IGFBP-2 in regulating Thecal cell proliferation and steroidogenesis during follicular development in cattle.
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insulin like growth factor binding protein 2 and 3 their biological effects in bovine Thecal Cells
Biology of Reproduction, 1997Co-Authors: L J Spicer, R E Stewart, P Alvarez, C. C. Francisco, B E KeeferAbstract:This study was aimed at testing the hypothesis that the insulin-like growth factor-binding proteins (IGFBP)-2 and -3 can modulate the hormone-dependent differentiation of Thecal Cells in vitro. Thecal Cells from large (> or = 8 mm) follicles were collected from cattle, cultured for 2 days in medium containing 10% fetal calf serum, washed, and then treated for an additional 2 days in serum-free medium with bovine LH (100 ng/ml), recombinant human insulin-like growth factor (IGF)-I (0 or 30 ng/ml), recombinant human IGFBP-2 (0, 200, or 400 ng/ml; i.e., 0, 6.5, or 12.9 nM), or recombinant human IGFBP-3 (0, 200, or 400 ng/ml; i.e., 0, 4.3, or 8.5 nM). IGFBP-2 (200 and 400 ng/ml) inhibited (p 0.10) progesterone production or Thecal cell proliferation in the presence of LH and/or IGF-I. In contrast, IGFBP-3 (200 ng/ml) inhibited the IGF-I-induced increase in Thecal cell numbers by 76%, and Thecal cell progesterone and androstenedione production by 52% and 89%, respectively. A higher dose of IGF-I (i.e., 100 ng/ml) overcame the inhibitory effects of IGFBP-3 on IGF-I-induced cell proliferation and on progesterone and androstenedione production by Thecal Cells. As with IGFBP-2, IGFBP-3 had no effect (p > 0.10) on LH-induced progesterone or androstenedione production by Thecal Cells in the absence of IGF-I. Both IGFBP-2 and IGFBP-3 directly inhibited [125I]IGF-I and -II binding to Thecal Cells; IGFBP-2 was a weaker inhibitor of Thecal [125I]IGF-I and -II binding than IGFBP-3. These results indicate that IGFBP-3 has a more pronounced inhibitory effect than IGFBP-2 on IGF-I action in cultured bovine Thecal Cells. Thus, IGFBP-3 may play a more significant role than IGFBP-2 in regulating Thecal cell proliferation and steroidogenesis during follicular development in cattle.
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interaction among bovine somatotropin insulin and gonadotropins on steroid production by bovine granulosa and Thecal Cells
Journal of Dairy Science, 1996Co-Authors: L J Spicer, R E StewartAbstract:Abstract The objective of the present study was to determine the interactions among bST, insulin, and gonadotropins on steroid production by granulosa and Thecal Cells from bovine follicles. Basal production of estradiol by granulosa Cells from small (1 to 5mm) and large (≥8mm) follicles (expressed as picograms of estradiol per 10 5 Cells per 24h) was not affected by 50 or 300ng/ml of bST, but 300ng/ml of bST inhibited estradiol production that was induced by FSH plus insulin in Cells from small and large follicles. Progesterone production and proliferation by granulosa Cells from large follicles were not affected by 3 to 100ng/ml of bST. In cultures of Thecal Cells that exhibited a >3-fold increase in androstenedione production induced by LH, 3 to 30ng/ml of bST further increased androstenedione production by 29 to 42%) but cell proliferation and progesterone production were unaffected by bST. In cultures of Thecal Cells that exhibited a
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Interaction Among Bovine Somatotropin, Insulin, and Gonadotropins on Steroid Production by Bovine Granulosa and Thecal Cells
Journal of dairy science, 1996Co-Authors: Leon J. Spicer, R E StewartAbstract:The objective of the present study was to determine the interactions among bST, insulin, and gonadotropins on steroid production by granulosa and Thecal Cells from bovine follicles. Basal production of estradiol by granulosa Cells from small (1 to 5 mm) and large (> or = 8 mm) follicles (expressed as picograms of estradiol per 10(5) Cells per 24 h) was not affected by 50 or 300 ng/ml of bST, but 300 ng/ml of bST inhibited estradiol production that was induced by FSH plus insulin in Cells from small and large follicles. Progesterone production and proliferation by granulosa Cells from large follicles were not affected by 3 to 100 ng/ml of bST. In cultures of Thecal Cells that exhibited a > 3-fold increase in androstenedione production induced by LH, 3 to 30 ng/ml of bST further increased androstenedione production by 29 to 42%, but cell proliferation and progesterone production were unaffected by bST. In cultures of Thecal Cells that exhibited a < 2-fold increase in androstenedione production induced by LH, 3 to 30 ng/ml of bST inhibited androstenedione production by 32 to 33% and inhibited cell proliferation by 9 to 13%, but progesterone was unaffected by bST. In summary, only pharmacologic doses of bST inhibited estradiol production by granulosa Cells, but physiologic doses of bST altered androstenedione production by Thecal Cells, which indicated that bST might not have an important role in granulosa cell function but might play a role in Thecal cell function in cattle.
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interactions among basic fibroblast growth factor epidermal growth factor insulin and insulin like growth factor i igf i on cell numbers and steroidogenesis of bovine Thecal Cells role of igf i receptors
Biology of Reproduction, 1996Co-Authors: L J Spicer, R E StewartAbstract:The objectives of the present study were to determine the interaction among basic fibroblast growth factor (bFGF), epidermal growth factor (EGF), insulin, and insulin-like growth factor-I (IGF-I) on cell numbers, steroidogenesis, and IGF-I binding sites in cultured Thecal Cells. Cells from large (> or = 8 mm) follicles were collected from cattle and cultured for 4 days. Treatment with 1-30 ng/ml of bFGF for 2 days increased (p < 0.05) Thecal cell numbers but inhibited (p < 0.05) androstenedione and progesterone production in the presence of insulin alone or insulin plus LH. Treatment with 1-30 ng/ml of bFGF for 2 days also inhibited (p < 0.05) the number of specific 125I-IGF-I binding sites in Thecal Cells, with maximal inhibition being detected at 1 ng/ml; coculture with 100 ng/ml LH did not influence this effect. In the absence of bFGF and the presence of LH, 30 ng/ml of IGF-I increased Thecal cell numbers and production of androstenedione and progesterone. However, cotreatment with 10 ng/ml bFGF inhibited Thecal cell response to IGF-I. Cotreatment consisting of 3-100 ng/ml EGF with insulin increased (p < 0.05) Thecal cell numbers but decreased (p < 0.05) androstenedione and progesterone production and the number of specific 125I-IGF-I binding sites in Thecal Cells, with maximal inhibition observed at 3 ng/ml of EGF. Also, cotreatment consisting of 3 and 10 ng/ml of EGF with IGF-I plus LH inhibited (p < 0.05) cell numbers and production of androstenedione and progesterone by Thecal Cells. These results suggest that bFGF, EGF, insulin, and IGF-I may interact to play a significant role in basal and LH-modulated Thecal cell steroidogenesis and mitogenesis during follicular development in cattle.
Raymond J. Rodgers - One of the best experts on this subject based on the ideXlab platform.
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Top 50 genes that were most differentially up regulated in vitro in Thecal Cells.
2017Co-Authors: Nicholas Hatzirodos, Claire Glister, Katja Hummitzsch, Helen F. Irving-rodgers, Philip G. Knight, Raymond J. RodgersAbstract:Top 50 genes that were most differentially up regulated in vitro in Thecal Cells.
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Top 50 genes that were most differentially down regulated in vitro in Thecal Cells.
2017Co-Authors: Nicholas Hatzirodos, Claire Glister, Katja Hummitzsch, Helen F. Irving-rodgers, Philip G. Knight, Raymond J. RodgersAbstract:Top 50 genes that were most differentially down regulated in vitro in Thecal Cells.
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Appearance of Granulosa Cells (GC) and Thecal Cells (TC) cultured under serum-free conditions for 48, 96 and 144 hours.
2017Co-Authors: Nicholas Hatzirodos, Claire Glister, Katja Hummitzsch, Helen F. Irving-rodgers, Philip G. Knight, Raymond J. RodgersAbstract:Appearance of Granulosa Cells (GC) and Thecal Cells (TC) cultured under serum-free conditions for 48, 96 and 144 hours.
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226 expression of matrix metalloproteinases in bovine Thecal Cells
Reproduction Fertility and Development, 2005Co-Authors: L Harland, Helen F Irvingrodgers, Stephanie E Morris, Raymond J. RodgersAbstract:As follicles grow the Thecal layers expand. It is likely that extracellular matrix is remodelled in this process and possibly by matrix metalloproteinases (MMPs). A promising candidate to regulate MMPs is insulin-like factor 3 (INSL3). It is produced by Thecal Cells, its receptor, LGR8, is expressed in the theca interna (unpublished) and a related molecule, relaxin, regulates turnover of matrix in a number of tissues. For this reason we sort to examine the role of INSL3 in matrix turnover. However, in all Thecal cell culture systems examined LGR8 receptors appear to be down regulated within 24 h. We therefore examined the effects of second messenger pathway activators. Thecal and granulosa Cells were isolated and cultured and the levels of RNA for MMP2 and 9 quantitated by RT-PCR. MMP2 mRNA levels in Thecal tissues were >10 fold higher than in granulosa Cells (n = 19 follicles >10 mm). MMP2 levels were substantially greater than MMP9. At 12 h phorbol ester (100 nM phorbol 12,13-didecanoate) increased Thecal expression of MMP 9 mRNA levels 11.5 fold (P < 0.001) and at 48 h MMP2 mRNA was increased 5 fold (P < 0.01). Pieces of whole follicle wall [follicles <5 mm in diameter, classified as healthy (n = 12) or atretic (n = 6)] were cultured in serum free media. Expression of the steroidogenic enzymes 17β HSD and P450scc but not 3β HSD were detected by immunohistochemistry even after 10 days. MMP activity on day 2 was analysed by gelatin zymography. Treatment with phorbol ester increased active MMP9 19 fold (P < 0.001). Treatment of Thecal Cells or follicle walls with 1 mM dibutyryl cAMP induced additional MMP activities at sizes of 110 and 122kDa. No effects on MMP2 activity were observed. In conclusion whilst we do not know the ligand inducers of the synthesis and activator of MMPs in Thecal Cells they can be regulated. Hence MMPs are candidates for remodelling the extracellular matrix of Thecal layers.
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226. Expression of matrix metalloproteinases in bovine Thecal Cells
Reproduction Fertility and Development, 2005Co-Authors: L Harland, Helen F. Irving-rodgers, Stephanie E Morris, Raymond J. RodgersAbstract:As follicles grow the Thecal layers expand. It is likely that extracellular matrix is remodelled in this process and possibly by matrix metalloproteinases (MMPs). A promising candidate to regulate MMPs is insulin-like factor 3 (INSL3). It is produced by Thecal Cells, its receptor, LGR8, is expressed in the theca interna (unpublished) and a related molecule, relaxin, regulates turnover of matrix in a number of tissues. For this reason we sort to examine the role of INSL3 in matrix turnover. However, in all Thecal cell culture systems examined LGR8 receptors appear to be down regulated within 24 h. We therefore examined the effects of second messenger pathway activators. Thecal and granulosa Cells were isolated and cultured and the levels of RNA for MMP2 and 9 quantitated by RT-PCR. MMP2 mRNA levels in Thecal tissues were >10 fold higher than in granulosa Cells (n = 19 follicles >10 mm). MMP2 levels were substantially greater than MMP9. At 12 h phorbol ester (100 nM phorbol 12,13-didecanoate) increased Thecal expression of MMP 9 mRNA levels 11.5 fold (P < 0.001) and at 48 h MMP2 mRNA was increased 5 fold (P < 0.01). Pieces of whole follicle wall [follicles
James C Garmey - One of the best experts on this subject based on the ideXlab platform.
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troglitazone an insulin sensitizing thiazolidinedione represses combined stimulation by lh and insulin of de novo androgen biosynthesis by Thecal Cells in vitro
The Journal of Clinical Endocrinology and Metabolism, 2002Co-Authors: Johannes D. Veldhuis, George Zhang, James C GarmeyAbstract:Polycystic ovarian syndrome (anovulatory hyperandrogenism) is marked by adolescent onset of systemic hyperinsulinism, oligoovulation, hirsutism, excessive LH and androgen secretion, and variable reduction in fertility. Insulin and LH are believed to act in concert to promote ovarian androgen hypersecretion in this disorder. Administration of troglitazone, an insulin-sensitizing agent and putative PPARγ agonist, can decrease hyperinsulinism, suppress T production, and ameliorate oligoovulation in some women with this endocrinopathy. The present study tests the hypothesis that troglitazone directly inhibits de novo androgen biosynthesis stimulated jointly by LH and insulin in primary cultures of (porcine) Thecal Cells. We show that troglitazone dose-dependently antagonizes LH/insulin’s combined stimulation of androstenedione and T production by Thecal Cells in vitro. Consistent steroidogenic inhibition of 80–95% was achieved at drug concentrations of 3–6.8 μm (P < 0.001). Exposure of Thecal Cells to the thi...
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Troglitazone, an insulin-sensitizing thiazolidinedione, represses combined stimulation by LH and insulin of de novo androgen biosynthesis by Thecal Cells in vitro.
The Journal of clinical endocrinology and metabolism, 2002Co-Authors: Johannes D. Veldhuis, George Zhang, James C GarmeyAbstract:Polycystic ovarian syndrome (anovulatory hyperandrogenism) is marked by adolescent onset of systemic hyperinsulinism, oligoovulation, hirsutism, excessive LH and androgen secretion, and variable reduction in fertility. Insulin and LH are believed to act in concert to promote ovarian androgen hypersecretion in this disorder. Administration of troglitazone, an insulin-sensitizing agent and putative PPAR gamma agonist, can decrease hyperinsulinism, suppress T production, and ameliorate oligoovulation in some women with this endocrinopathy. The present study tests the hypothesis that troglitazone directly inhibits de novo androgen biosynthesis stimulated jointly by LH and insulin in primary cultures of (porcine) Thecal Cells. We show that troglitazone dose-dependently antagonizes LH/insulin's combined stimulation of androstenedione and T production by Thecal Cells in vitro. Consistent steroidogenic inhibition of 80-95% was achieved at drug concentrations of 3-6.8 microM (P < 0.001). Exposure of Thecal Cells to the thiazolidinedione derivative also blocked bihormonally stimulated accumulation of CYP17 (cytochrome P450 17 alpha-hydroxylase/C(17-20) lyase) gene expression, as reflected by decreased accumulation of cognate heterogeneous nuclear RNA and mRNA (by 30-65%; P < 0.05). Moreover, troglitazone suppressed LH/insulin-induced phosphorylation of the 52-kDa immunoprecipitated CYP17 enzyme by 88% (P < 0.001). A putative natural agonist of PPAR gamma nuclear transcription, 15-deoxy-delta-12,14-prostaglandin J(2), also inhibited LH/insulin-driven androstenedione biosynthesis and CYP17 gene expression in Thecal Cells. In conclusion, a synthetic thiazolidinedione (troglitazone) and a natural ligand of PPAR gamma (15-deoxy-delta-12,14-prostaglandin J(2)) effectively impede the concerted stimulation by LH and insulin of in vitro Thecal cell androgen production, CYP17 gene expression, and CYP17 protein phosphorylation. This ensemble of inhibitory actions on LH/insulin-stimulated steroidogenesis offers a plausible mechanistic basis for at least part of the observed clinical efficacy of troglitazone in mitigating androgen excess in women with polycystic ovarian syndrome.
