The Experts below are selected from a list of 9 Experts worldwide ranked by ideXlab platform
Michal Lahav - One of the best experts on this subject based on the ideXlab platform.
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dependence on prolactin of the luteolytic effect of prostaglandin f2α in rat luteal cell cultures
Biology of Reproduction, 2001Co-Authors: Anna Zetser, Tatiana Kisliouk, Emma Ivakin, Michal LahavAbstract:Luteal regression is a multistep, prolonged process, and long-term luteal cultures are required for studying it in vitro. Cell suspensions from ovaries of superovulated rats were enriched with steroidogenic cells, seeded on laminin or fibronectin, and maintained in defined medium for up to 10 days. Progesterone secretion was much lower than that of 20alpha-Dihydroprogesterone, a product of 20alpha-hydroxysteroid dehydrogenase (20alpha-HSD). Prolactin added throughout the incubation period gradually increased the percent progesterone out of total progestins to fourfold, while reducing 20alpha-HSD mRNA by 73%. Luteinizing hormone accelerated the establishment of higher percent progesterone by prolactin but by itself had no effect. Prolactin did not increase total progestin production or cytochrome P450 side-chain cleavage (P450(scc)) mRNA. Cell viability was unaffected by prolactin and/or LH. Prostaglandin F2alpha (PGF2alpha) was added 7-8 days after seeding. In prolactin-treated cells, PGF2alpha reduced steroidogenesis after 4-45 h, and at 45 h total progestins and P450(scc) mRNA were reduced by 45%. At 8-45 h PGF2alpha reduced the percent progesterone out of total progestins, and at 45 h 20alpha-HSD mRNA was doubled. In contrast, in prolactin-deprived cultures, PGF2alpha had little effect on total progestins or 20alpha-HSD mRNA but doubled P450(scc) mRNA. Phospholipase C activity was stimulated by PGF2alpha regardless of prolactin. Thus, when prolactin-treated, our cultures are a good model for mature corpora lutea challenged with PGF2alpha; the finding that without prolactin PGF2alpha has an alternative set of actions could help in identifying the signaling pathways of PGF2alpha responsible for its luteolytic effects.
Anna Zetser - One of the best experts on this subject based on the ideXlab platform.
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dependence on prolactin of the luteolytic effect of prostaglandin f2α in rat luteal cell cultures
Biology of Reproduction, 2001Co-Authors: Anna Zetser, Tatiana Kisliouk, Emma Ivakin, Michal LahavAbstract:Luteal regression is a multistep, prolonged process, and long-term luteal cultures are required for studying it in vitro. Cell suspensions from ovaries of superovulated rats were enriched with steroidogenic cells, seeded on laminin or fibronectin, and maintained in defined medium for up to 10 days. Progesterone secretion was much lower than that of 20alpha-Dihydroprogesterone, a product of 20alpha-hydroxysteroid dehydrogenase (20alpha-HSD). Prolactin added throughout the incubation period gradually increased the percent progesterone out of total progestins to fourfold, while reducing 20alpha-HSD mRNA by 73%. Luteinizing hormone accelerated the establishment of higher percent progesterone by prolactin but by itself had no effect. Prolactin did not increase total progestin production or cytochrome P450 side-chain cleavage (P450(scc)) mRNA. Cell viability was unaffected by prolactin and/or LH. Prostaglandin F2alpha (PGF2alpha) was added 7-8 days after seeding. In prolactin-treated cells, PGF2alpha reduced steroidogenesis after 4-45 h, and at 45 h total progestins and P450(scc) mRNA were reduced by 45%. At 8-45 h PGF2alpha reduced the percent progesterone out of total progestins, and at 45 h 20alpha-HSD mRNA was doubled. In contrast, in prolactin-deprived cultures, PGF2alpha had little effect on total progestins or 20alpha-HSD mRNA but doubled P450(scc) mRNA. Phospholipase C activity was stimulated by PGF2alpha regardless of prolactin. Thus, when prolactin-treated, our cultures are a good model for mature corpora lutea challenged with PGF2alpha; the finding that without prolactin PGF2alpha has an alternative set of actions could help in identifying the signaling pathways of PGF2alpha responsible for its luteolytic effects.
G Chetrite - One of the best experts on this subject based on the ideXlab platform.
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the anti aromatase effect of progesterone and of its natural metabolites 20alpha and 5alpha Dihydroprogesterone in the mcf 7aro breast cancer cell line
Anticancer Research, 2008Co-Authors: J R Pasqualini, G ChetriteAbstract:BACKGROUND Progesterone is metabolized in the normal breast mainly into 4-ene-pregnenes (e.g. 20alpha-Dihydroprogesterone, 20alphaDHP) but, in contrast, in breast cancer tissue the 5alpha-dihydropregnanes (e.g. 5alpha-Dihydroprogesterone, 5alphaDHP) are prevalent. In the present study the effect of progesterone and its main metabolites 20alphaDHP and 5alphaDHP on the aromatase activity in a stable aromatase-expressing estrogen receptor-positive human breast cancer cell line, MCF-7aro, was explored. MATERIALS AND METHODS The MCF-7aro cells were stripped of endogenous steroids and incubated with physiological concentrations of [3H]-testosterone ([3H]-testos: 5 x 10(-9)M) alone or in the presence of progesterone, 20alphaDHP or 5alphaDHP (5 x 10(-6) or 5 x 10(-8)M) for 24 h at 37 degrees C. The cellular radioactivity uptake was determined in the ethanolic supernatant and the DNA content in the remaining pellet. [3H]-Estradiol (E2), [3H]-estrone (E1) and [3H]-testos were characterized by thin layer chromatography and quantified using the corresponding standard. RESULTS Aromatase activity was present at a high level in the MCF-7aro cells after incubation with [3H]-testos when the concentration of [3H]-E2 was 3.70 pmol/mg DNA; 20alphaDHP at concentrations of 5 x 10(-6)M or 5 x 10(-8)M significantly inhibited this conversion by 50.3% and 36.5%, respectively. No significant effect was found with the metabolite 5alphaDHP or the parent hormone, progesterone. CONCLUSION The MCF-7aro cell line shows high detectable aromatase activity. The present data indicate that the progesterone metabolite 20alphaDHP, found mainly in normal breast tissue, can act as an anti-aromatase agent.
Tatiana Kisliouk - One of the best experts on this subject based on the ideXlab platform.
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dependence on prolactin of the luteolytic effect of prostaglandin f2α in rat luteal cell cultures
Biology of Reproduction, 2001Co-Authors: Anna Zetser, Tatiana Kisliouk, Emma Ivakin, Michal LahavAbstract:Luteal regression is a multistep, prolonged process, and long-term luteal cultures are required for studying it in vitro. Cell suspensions from ovaries of superovulated rats were enriched with steroidogenic cells, seeded on laminin or fibronectin, and maintained in defined medium for up to 10 days. Progesterone secretion was much lower than that of 20alpha-Dihydroprogesterone, a product of 20alpha-hydroxysteroid dehydrogenase (20alpha-HSD). Prolactin added throughout the incubation period gradually increased the percent progesterone out of total progestins to fourfold, while reducing 20alpha-HSD mRNA by 73%. Luteinizing hormone accelerated the establishment of higher percent progesterone by prolactin but by itself had no effect. Prolactin did not increase total progestin production or cytochrome P450 side-chain cleavage (P450(scc)) mRNA. Cell viability was unaffected by prolactin and/or LH. Prostaglandin F2alpha (PGF2alpha) was added 7-8 days after seeding. In prolactin-treated cells, PGF2alpha reduced steroidogenesis after 4-45 h, and at 45 h total progestins and P450(scc) mRNA were reduced by 45%. At 8-45 h PGF2alpha reduced the percent progesterone out of total progestins, and at 45 h 20alpha-HSD mRNA was doubled. In contrast, in prolactin-deprived cultures, PGF2alpha had little effect on total progestins or 20alpha-HSD mRNA but doubled P450(scc) mRNA. Phospholipase C activity was stimulated by PGF2alpha regardless of prolactin. Thus, when prolactin-treated, our cultures are a good model for mature corpora lutea challenged with PGF2alpha; the finding that without prolactin PGF2alpha has an alternative set of actions could help in identifying the signaling pathways of PGF2alpha responsible for its luteolytic effects.
Emma Ivakin - One of the best experts on this subject based on the ideXlab platform.
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dependence on prolactin of the luteolytic effect of prostaglandin f2α in rat luteal cell cultures
Biology of Reproduction, 2001Co-Authors: Anna Zetser, Tatiana Kisliouk, Emma Ivakin, Michal LahavAbstract:Luteal regression is a multistep, prolonged process, and long-term luteal cultures are required for studying it in vitro. Cell suspensions from ovaries of superovulated rats were enriched with steroidogenic cells, seeded on laminin or fibronectin, and maintained in defined medium for up to 10 days. Progesterone secretion was much lower than that of 20alpha-Dihydroprogesterone, a product of 20alpha-hydroxysteroid dehydrogenase (20alpha-HSD). Prolactin added throughout the incubation period gradually increased the percent progesterone out of total progestins to fourfold, while reducing 20alpha-HSD mRNA by 73%. Luteinizing hormone accelerated the establishment of higher percent progesterone by prolactin but by itself had no effect. Prolactin did not increase total progestin production or cytochrome P450 side-chain cleavage (P450(scc)) mRNA. Cell viability was unaffected by prolactin and/or LH. Prostaglandin F2alpha (PGF2alpha) was added 7-8 days after seeding. In prolactin-treated cells, PGF2alpha reduced steroidogenesis after 4-45 h, and at 45 h total progestins and P450(scc) mRNA were reduced by 45%. At 8-45 h PGF2alpha reduced the percent progesterone out of total progestins, and at 45 h 20alpha-HSD mRNA was doubled. In contrast, in prolactin-deprived cultures, PGF2alpha had little effect on total progestins or 20alpha-HSD mRNA but doubled P450(scc) mRNA. Phospholipase C activity was stimulated by PGF2alpha regardless of prolactin. Thus, when prolactin-treated, our cultures are a good model for mature corpora lutea challenged with PGF2alpha; the finding that without prolactin PGF2alpha has an alternative set of actions could help in identifying the signaling pathways of PGF2alpha responsible for its luteolytic effects.
