Physiological effects of 1,25-dihydroxyvitamin D3 in TM4 Sertoli cell line.
1,25-Dihydroxyvitamin D3 [1,25(OH)2D3] receptors have been previously described in Sertoli cells. This study was performed to assess biological activity of the receptor in the mouse Sertoli cell line TM4. A 2-h preincubation with 0.01-25 nM 1,25(OH)2D3 resulted in a dose-dependent rapid uptake of 45Ca2+ within 5 min of addition of the isotope to the cells (27 +/- 8%, n = 4 experiments; P less than 0.05). This response was specific for 1,25(OH)2D3, in that it was not induced by 25-hydroxyvitamin D3, estradiol, cortisol, R 5020 (promegestone), or testosterone. However, a combination of testosterone and 1,25(OH)2D3 inhibited uptake by 23 +/- 8% (n = 3 experiments, P less than 0.01). That the mechanism responsible for 1,25(OH)2D3-stimulated uptake may involve 1,25(OH)2D3 receptor interaction is supported by the observation that cycloheximide inhibited the response. Conversely, there was no detectable change in uptake by 1,25(OH)2D3-treated cells after 24-h incubation with 0.1-5 nM 1,25(OH)2D3. Increased levels of DNA and protein content also resulted from a 2-h incubation with the steroid and were sustained up to 24 h without a concomitant increase in cell number or a detectable change in cell morphology. The presence of specific 1,25(OH)2D3 receptor-like binding sites was demonstrated by sucrose gradient analysis and hydroxylapatite assay. These data demonstrate that 1,25(OH)2D3 may play an important role in testicular function through regulation of receptor-mediated events.
Akerstrom
V L
VL
Department of Physiology, Tulane Medical School, New Orleans, Louisiana 70112.
Walters
M R
MR
D000818:Animals; D001665:Binding Sites; D001692:Biological Transport / Q000187:drug effects; D002112:Calcifediol / Q000494:pharmacology; D002117:Calcitriol / Q000378:metabolism / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D003513:Cycloheximide / Q000494:pharmacology; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D004958:Estradiol / Q000494:pharmacology; D006854:Hydrocortisone / Q000494:pharmacology; D007700:Kinetics; D008297:Male; D051379:Mice; D011397:Promegestone / Q000494:pharmacology; D011506:Proteins / Q000378:metabolism; D018167:Receptors, Calcitriol; D011987:Receptors, Steroid / Q000187:drug effects / Q000502:physiology; D012708:Sertoli Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D013739:Testosterone / Q000494:pharmacology
D011506:Proteins; D018167:Receptors, Calcitriol; D011987:Receptors, Steroid; D013739:Testosterone; D004958:Estradiol; D004247:DNA; D003513:Cycloheximide; D011397:Promegestone; D002117:Calcitriol; D002112:Calcifediol; D002118:Calcium; D006854:Hydrocortisone