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Walter E Stumpf - One of the best experts on this subject based on the ideXlab platform.
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Vitamin D (soltriol) target cells in the harderian gland of the Siberian hamster (Phodopus sungorus).
Cells Tissues Organs, 1993Co-Authors: María Del Mar Pérez-delgado, Andrzej Bartke, Hans-jürgen Bidmon, Walter E StumpfAbstract:Harderian glands of female and male Siberian hamsters (Phodopus sungorus) were studied after a subcutaneous injection of 3H-dihydroxycholecalciferol (vitamin D, soltriol). Autoradiograms revealed the
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vitamin d3 soltriol nuclear receptors in abdominal scent gland and skin of siberian hamster phodopus sungorus localized by autoradiography and immunohistochemistry
Histochemistry and Cell Biology, 1993Co-Authors: Walter E Stumpf, Maria De Mar Perezdelgado, Hans-jürgen Bidmon, Libo Li, Pentti TuohimaaAbstract:In vivo autoradiography with [3H]1,25-dihydroxycholecalciferol (vitamin D, soltriol) and immuno-staining with antibodies to vitamin D receptor were applied to identify specific binding sites in the abdominal scent gland of male Siberian hamster (Phodopus sungorus). Nuclear concentration of radiolabeled hormone and receptor antibodies was observed in the corresponding cell types including basal cells of sebaceous glands, cells of the outer hair sheaths and hair bulbs, and also keratinocytes in the epidermis. Cells of the hair dermal papillae and fibroblasts of the dermis did not show nuclear labeling. There was good correspondence between the autoradiographic and immunohistochemical data. The results indicate the presence of receptors for vitamin D-soltriol and suggest a seasonal regulation of scent gland marking activities by this steroid hormone of sunlight in cooperation with the sex steroid testosterone.
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Vitamin D (soltriol) target cells in the harderian gland of the Siberian hamster (Phodopus sungorus).
Acta anatomica, 1993Co-Authors: María Del Mar Pérez-delgado, Andrzej Bartke, Hans-jürgen Bidmon, Walter E StumpfAbstract:Harderian glands of female and male Siberian hamsters (Phodopus sungorus) were studied after a subcutaneous injection of 3H-dihydroxycholecalciferol (vitamin D, soltriol). Autoradiograms revealed the presence of nuclear concentration of the hormone in certain alveolar cells and in myoepithelial cells. The proportion of labeled cells varied between 5.5 and 19% of the total cell number, with an average of 9.5% in female and 12.4% in male hamsters. The data suggest that the functions of the Harderian gland could undergo seasonal changes under the control of vitamin D.
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vitamin d nuclear binding to neurons of the septal substriatal and amygdaloid area in the siberian hamster phodopus sungorus brain
Neuroscience, 1992Co-Authors: I M Musiol, Walter E Stumpf, Hans-jürgen Bidmon, Artur Mayerhofer, Christian Heiss, Andrzej BartkeAbstract:Autoradiographic experiments were performed on brains of Siberian hamsters (Phodopus sungorus) injected with tritiated 1,25-dihydroxycholecalciferol. Nuclear labeling was prevented in the presence of excess unlabeled hormone. Strong nuclear concentration of radioactivity was observed in neurons of the nucleus basalis of Meynert, the medial septal nucleus, the nucleus of the diagonal band of Broca and the central amygdaloid group. The latter has been defined as consisting of the central nucleus of the amygdala, its extension into the sublenticular part of the substantia innominata of Reichert, and the lateral division of the bed nucleus of the stria terminalis. All these structures have been reported to be involved in memory and other cognitive processes, and to be affected by age-dependent neurodegenerative disorders such as Alzheimer's disease. Corresponding localization of 1,25-dihydroxycholecalciferol receptor sites in these select basal forebrain nuclei of the Siberian hamster may implicate vitamin D (soltriol), the steroid hormone of sunlight, in memory processing.
Hans-jürgen Bidmon - One of the best experts on this subject based on the ideXlab platform.
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Vitamin D (soltriol) target cells in the harderian gland of the Siberian hamster (Phodopus sungorus).
Cells Tissues Organs, 1993Co-Authors: María Del Mar Pérez-delgado, Andrzej Bartke, Hans-jürgen Bidmon, Walter E StumpfAbstract:Harderian glands of female and male Siberian hamsters (Phodopus sungorus) were studied after a subcutaneous injection of 3H-dihydroxycholecalciferol (vitamin D, soltriol). Autoradiograms revealed the
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vitamin d3 soltriol nuclear receptors in abdominal scent gland and skin of siberian hamster phodopus sungorus localized by autoradiography and immunohistochemistry
Histochemistry and Cell Biology, 1993Co-Authors: Walter E Stumpf, Maria De Mar Perezdelgado, Hans-jürgen Bidmon, Libo Li, Pentti TuohimaaAbstract:In vivo autoradiography with [3H]1,25-dihydroxycholecalciferol (vitamin D, soltriol) and immuno-staining with antibodies to vitamin D receptor were applied to identify specific binding sites in the abdominal scent gland of male Siberian hamster (Phodopus sungorus). Nuclear concentration of radiolabeled hormone and receptor antibodies was observed in the corresponding cell types including basal cells of sebaceous glands, cells of the outer hair sheaths and hair bulbs, and also keratinocytes in the epidermis. Cells of the hair dermal papillae and fibroblasts of the dermis did not show nuclear labeling. There was good correspondence between the autoradiographic and immunohistochemical data. The results indicate the presence of receptors for vitamin D-soltriol and suggest a seasonal regulation of scent gland marking activities by this steroid hormone of sunlight in cooperation with the sex steroid testosterone.
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Vitamin D (soltriol) target cells in the harderian gland of the Siberian hamster (Phodopus sungorus).
Acta anatomica, 1993Co-Authors: María Del Mar Pérez-delgado, Andrzej Bartke, Hans-jürgen Bidmon, Walter E StumpfAbstract:Harderian glands of female and male Siberian hamsters (Phodopus sungorus) were studied after a subcutaneous injection of 3H-dihydroxycholecalciferol (vitamin D, soltriol). Autoradiograms revealed the presence of nuclear concentration of the hormone in certain alveolar cells and in myoepithelial cells. The proportion of labeled cells varied between 5.5 and 19% of the total cell number, with an average of 9.5% in female and 12.4% in male hamsters. The data suggest that the functions of the Harderian gland could undergo seasonal changes under the control of vitamin D.
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vitamin d nuclear binding to neurons of the septal substriatal and amygdaloid area in the siberian hamster phodopus sungorus brain
Neuroscience, 1992Co-Authors: I M Musiol, Walter E Stumpf, Hans-jürgen Bidmon, Artur Mayerhofer, Christian Heiss, Andrzej BartkeAbstract:Autoradiographic experiments were performed on brains of Siberian hamsters (Phodopus sungorus) injected with tritiated 1,25-dihydroxycholecalciferol. Nuclear labeling was prevented in the presence of excess unlabeled hormone. Strong nuclear concentration of radioactivity was observed in neurons of the nucleus basalis of Meynert, the medial septal nucleus, the nucleus of the diagonal band of Broca and the central amygdaloid group. The latter has been defined as consisting of the central nucleus of the amygdala, its extension into the sublenticular part of the substantia innominata of Reichert, and the lateral division of the bed nucleus of the stria terminalis. All these structures have been reported to be involved in memory and other cognitive processes, and to be affected by age-dependent neurodegenerative disorders such as Alzheimer's disease. Corresponding localization of 1,25-dihydroxycholecalciferol receptor sites in these select basal forebrain nuclei of the Siberian hamster may implicate vitamin D (soltriol), the steroid hormone of sunlight, in memory processing.
Andrzej Bartke - One of the best experts on this subject based on the ideXlab platform.
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Vitamin D (soltriol) target cells in the harderian gland of the Siberian hamster (Phodopus sungorus).
Cells Tissues Organs, 1993Co-Authors: María Del Mar Pérez-delgado, Andrzej Bartke, Hans-jürgen Bidmon, Walter E StumpfAbstract:Harderian glands of female and male Siberian hamsters (Phodopus sungorus) were studied after a subcutaneous injection of 3H-dihydroxycholecalciferol (vitamin D, soltriol). Autoradiograms revealed the
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Vitamin D (soltriol) target cells in the harderian gland of the Siberian hamster (Phodopus sungorus).
Acta anatomica, 1993Co-Authors: María Del Mar Pérez-delgado, Andrzej Bartke, Hans-jürgen Bidmon, Walter E StumpfAbstract:Harderian glands of female and male Siberian hamsters (Phodopus sungorus) were studied after a subcutaneous injection of 3H-dihydroxycholecalciferol (vitamin D, soltriol). Autoradiograms revealed the presence of nuclear concentration of the hormone in certain alveolar cells and in myoepithelial cells. The proportion of labeled cells varied between 5.5 and 19% of the total cell number, with an average of 9.5% in female and 12.4% in male hamsters. The data suggest that the functions of the Harderian gland could undergo seasonal changes under the control of vitamin D.
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vitamin d nuclear binding to neurons of the septal substriatal and amygdaloid area in the siberian hamster phodopus sungorus brain
Neuroscience, 1992Co-Authors: I M Musiol, Walter E Stumpf, Hans-jürgen Bidmon, Artur Mayerhofer, Christian Heiss, Andrzej BartkeAbstract:Autoradiographic experiments were performed on brains of Siberian hamsters (Phodopus sungorus) injected with tritiated 1,25-dihydroxycholecalciferol. Nuclear labeling was prevented in the presence of excess unlabeled hormone. Strong nuclear concentration of radioactivity was observed in neurons of the nucleus basalis of Meynert, the medial septal nucleus, the nucleus of the diagonal band of Broca and the central amygdaloid group. The latter has been defined as consisting of the central nucleus of the amygdala, its extension into the sublenticular part of the substantia innominata of Reichert, and the lateral division of the bed nucleus of the stria terminalis. All these structures have been reported to be involved in memory and other cognitive processes, and to be affected by age-dependent neurodegenerative disorders such as Alzheimer's disease. Corresponding localization of 1,25-dihydroxycholecalciferol receptor sites in these select basal forebrain nuclei of the Siberian hamster may implicate vitamin D (soltriol), the steroid hormone of sunlight, in memory processing.
Donald L Trump - One of the best experts on this subject based on the ideXlab platform.
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calcitriol 1 25 dihydroxycholecalciferol enhances paclitaxel antitumor activity in vitro and in vivo and accelerates paclitaxel induced apoptosis
Clinical Cancer Research, 2001Co-Authors: Pamela A. Hershberger, Ruth A Modzelewski, Robert M Rueger, Candace S. Johnson, Wei Dong Yu, Donald L TrumpAbstract:We demonstrated that calcitriol has antiproliferative activity in squamous cell carcinoma and prostatic adenocarcinoma and enhances the antitumor activity of platinum-based agents. In this study, we examined whether calcitriol also increases paclitaxel cytotoxicity. The effect of treatment on growth of the murine squamous cell carcinoma (SCCVII/SF) and human prostatic adenocarcinoma (PC-3) was determined by clonogenic assay, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, and monitoring tumor growth. Treatment of SCC or PC-3 cells in vitro with calcitriol prior to paclitaxel significantly reduced clonogenic survival compared with either agent alone. Median-dose effect analysis revealed that calcitriol and paclitaxel interact synergistically. Treatment of SCC or PC-3 tumor-bearing mice with calcitriol prior to paclitaxel resulted in substantially greater growth inhibition than was achieved with either agent alone, supporting the combined use of calcitriol and paclitaxel in the treatment of solid tumors. To explore the molecular basis for the enhanced antitumor activity of this combination, the effect of treatment on p21 Waf-1 (p21), Bcl-2, and poly(ADP-ribose) polymerase expression was evaluated in PC-3. A 72-h pretreatment with calcitriol reduced p21 expression and increased paclitaxel cytotoxicity (measured after 24 h) without evidence of apoptosis [poly(ADP-ribose) polymerase cleavage]. After 48 h, paclitaxel induced apoptosis, the extent of which was increased similarly by pretreatment or concurrent treatment with calcitriol. We therefore propose a model for calcitriol enhancement of paclitaxel cytotoxicity in which the “early” (24 h) effects are schedule dependent and not attributed to enhancement of paclitaxel-induced apoptosis. In contrast, the “delayed” (48-h) enhancement of paclitaxel activity by calcitriol is schedule independent and associated with acceleration of apoptosis.
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a phase i trial of calcitriol 1 25 dihydroxycholecalciferol in patients with advanced malignancy
Clinical Cancer Research, 1999Co-Authors: David C Smith, Candace S. Johnson, Catherine C Freeman, Josephia R Muindi, John W Wilson, Donald L TrumpAbstract:Vitamin D is a steroid hormone best known for its activity in regulating calcium and bone metabolism. Epidemiological evidence suggests that vitamin D may play a role in inhibiting the development of colon and prostate cancer. Vitamin D receptors are expressed in many types of malignant cells; in vitro and in vivo vitamin D and vitamin D analogues are active in suppressing the development and inhibiting the growth of numerous human and animal tumors. The major toxicity of the active form of vitamin D, 1,25-dihydroxycholecalciferol (calcitriol), is the induction of hypercalcemia. There are no data indicating the maximum tolerated dose of calcitriol administered every other day (QOD) s.c. We hypothesized that this route and schedule would permit administration of higher doses of calcitriol, which might have anticancer activity. We conducted a Phase I trial of calcitriol given s.c. QOD in patients with advanced solid tumors. Thirty-six patients were entered at doses ranging from 2 to 10 mg QOD; dose-limiting toxicity (hypercalcemia) occurred in three of three patients entered at the 10-mg QOD dose. Hypercalciuria occurred at all dose levels examined. No other toxicity was seen. Assessment of serum calcitriol concentrations by a RIA revealed a decrease in concentration-time curves on day 7 compared to day 1 of therapy. A dose-dependent increase in peak serum level and estimated area under the concentration-time curve was seen. The maximum serum levels occurred at the 10-mg QOD dose: 288 6 74 and 321 6 36 pg/ml at days 1 and 7, respectively. The normal range of calcitriol serum concentration, determined using this assay, is 16 ‐56 pg/ml. Serum calcitriol levels were maintained at near peak concentrations for at least 8 h following s.c. injection. This study indicates that substantial doses of calcitriol can be administered via this route with tolerable toxicity. Studies to explore approaches to ameliorate the hypercalcemia induced by calcitriol and to explore alternative schedules and interactions with other agents are warranted.
H A W Hazewinkel - One of the best experts on this subject based on the ideXlab platform.
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growth hormone modulates cholecalciferol metabolism with moderate effects on intestinal mineral absorption and specific effects on bone formation in growing dogs raised on balanced food
Domestic Animal Endocrinology, 2003Co-Authors: Marianna A Tryfonidou, M S Holl, M A Oosterlakendijksterhuis, M Vastenburg, W E Van Den Brom, H A W HazewinkelAbstract:Abstract The aim of the study was to investigate the influence of growth hormone (GH) on Vitamin D 3 metabolism and the subsequent effects on calcium (Ca) homeostasis and skeletal growth in growing dogs. A group of Miniature Poodles received supraphysiological doses of GH ( GH group; n =6; 0.5 IU GH per kg body per day) from 12 to 21 weeks of age and was compared with a control placebo-treated group ( n =8). Biologic activity of GH in the GH compared to the control group was indicated by (a) the 2.5- to 3.5-fold increase in the plasma concentrations of insulin-like growth factor I (IGF-I), (b) the increased production of 1,25-dihydroxycholecalciferol as indicated by the significantly increased plasma 1,25-dihydroxycholecalciferol concentrations and the 12.9-fold increase in renal 1α-hydroxylase gene expression, and (c) the inhibited production of 24,25-dihydroxycholecalciferol as indicated by the significantly lower plasma 24,25-dihydroxycholecalciferol concentrations and the similar levels of renal 24-hydroxylase gene expression. Despite the distinct effects on Vitamin D 3 metabolism in the GH group, there were only moderate effects on the intestine, i.e. at 20 weeks of age there was a significant increase of 14.4 and 5.6% in fractional absorption of Ca and phosphate (P i ), respectively, compared to the control group. GH administration resulted in significantly elevated glomerular filtration rate, with no differences in P i urine excretion as a result of a concomitant increase in the tubular reabsorption of P i . GH had only limited disturbing effects on endochondral ossification as indicated by the maintenance of the regularity of the growth plates. However, GH had specific anabolic effects on bone formation without concomitant effect on bone resorption that may result in disorders of skeletal remodeling and manifestation of enostosis.
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dietary 135 fold cholecalciferol supplementation severely disturbs the endochondral ossification in growing dogs
Domestic Animal Endocrinology, 2003Co-Authors: Marianna A Tryfonidou, Hector F. Deluca, M S Holl, M A Oosterlakendijksterhuis, W E Van Den Brom, J J Stevenhagen, C J Buurman, J P T M Van Leeuwen, H A W HazewinkelAbstract:The effects of excessive non-toxic dietary Vitamin D3 supplementation on Ca homeostasis with specific effects on endochondral ossification and skeletal remodeling were investigated in a group of growing Great Dane dogs supplemented with cholecalciferol (Vitamin D3; HVitD) versus a control group (CVitD) (1350 μg versus 11.4 μg Vitamin D3 per kilogram diet) from 6 to 21 weeks of age. There were no differences between groups in plasma concentrations of total Ca, inorganic phosphate, growth hormone, and insulin-like growth factor I and no signs of Vitamin D3 intoxication in HVitD. For the duration of the study in HVitD compared to CVitD, plasma levels of parathyroid hormone (PTH) decreased, calcitonin (CT) increased, 25-hydroxycholecalciferol [25(OH)D3] increased 30- to 75-fold, 24,25-dihydroxycholecalciferol [24,25(OH)2D3] increased 12- to 16-fold, and 1,25-dihydroxycholecalciferol [1,25(OH)2D3] decreased by approximately 40%. The latter was attributed to the two-fold increased metabolic clearance rate in the HVitD versus CVitD accompanied by the absence of the anabolic effect of PTH on the production of 1,25(OH)2D3. Fractional Ca absorption (α) did not differ between groups at 8 and 14 weeks of age, whereas at 20 weeks of age α increased by only 16.4% in HViAtD compared to CVitD. Excessive non-toxic Vitamin D3 supplementation resulted in decreased bone remodeling and focal enlargement of the growth plate with morphology resembling those induced by administration of CT. Hypercalcitoninemia and the imbalanced relationship between 1,25(OH)2D3 and 24,25(OH)2D3 are potent candidates for the disturbed endochondral ossification. © 2003 Elsevier Science Inc. All rights reserved.