|
|
||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Testis |
Division of Reproductive Biology, Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland 21205
In the rat, quantitatively normal spermatogenesis is maintained only when intratesticular testosterone (ITT) levels greatly exceed the peripheral T concentration. When ITT concentrations fall below a threshold, germ cells are lost at specific stages of the seminiferous cycle. Germ cells can be restored by high doses of T that binds to androgen receptors (AR) in Sertoli cells. However, the relationships between germ cell dynamics, AR-mediated molecular events, and ITT concentrations are not established. ITT levels may regulate germ cell life and death through an effect on AR localization and AR mRNA or protein levels within Sertoli cells at specific stages of the cycle. We determined AR localization and mRNA and protein expression in adult rat Sertoli cells in relation to reduced and then restored ITT concentrations in vivo. ITT levels were reduced by implanting rats with T- and estradiol (E)-filled capsules for 728 days and subsequently restored with large T-filled capsules. AR is normally localized within Sertoli cell nuclei at stages VIIVIII of the seminiferous epithelium. After T/E treatment, AR immunostaining in Sertoli cell nuclei became nondetectable by 1428 days but was restored 6 h following T restoration. The loss of Sertoli cell nuclear AR localization correlated with increasing numbers of apoptotic germ cells. AR mRNA levels in isolated Sertoli cells did not change through 14 days of T/E treatment, increased significantly by Day 28, and remained elevated 24 h after T restoration. AR mRNA levels in microdissected tubules at stages IIIV, VIVIII, and IXXII did not decrease through 14 days of T/E treatment. In contrast, AR protein levels were reduced in seminiferous tubules by Day 14 and in testes at Day 28 post-T/E treatment but were restored within 24 h by T repletion. Therefore, the reduction of ITT concentration results in a time-dependent redistribution of AR and reduced AR protein but not AR mRNA levels in Sertoli cells. Repletion of T restored AR protein and it relocated to Sertoli cell nuclei. By an unknown mechanism, T regulates AR localization within Sertoli cells to determine germ cell life or death.
2 Correspondence: Terry R. Brown, Division of Reproductive Biology, Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, Room W3606, 615 North Wolfe St., Baltimore, MD 21205. FAX: 410 614 2356; tbrown{at}jhsph.edu
3 Current address: Washington State University, Center of Reproductive Biology, Pullman, WA 99164
This article has been cited by other articles:
![]() |
Z. Zhang, J. Hill, M. Holland, Y. Kurihara, and K. L. Loveland Bovine Sertoli Cells Colonize and Form Tubules in Murine Hosts Following Transplantation and Grafting Procedures J Androl, July 1, 2008; 29(4): 418 - 430. [Abstract] [Full Text] [PDF] |
||||
![]() |
R.-S. Wang, S. Yeh, L.-M. Chen, H.-Y. Lin, C. Zhang, J. Ni, C.-C. Wu, P. A. di Sant'Agnese, K. L. deMesy-Bentley, C.-R. Tzeng, et al. Androgen Receptor in Sertoli Cell Is Essential for Germ Cell Nursery and Junctional Complex Formation in Mouse Testes Endocrinology, December 1, 2006; 147(12): 5624 - 5633. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. J. Asirvatham, M. Schmidt, B. Gao, and J. Chaudhary Androgens Regulate the Immune/Inflammatory Response and Cell Survival Pathways in Rat Ventral Prostate Epithelial Cells Endocrinology, January 1, 2006; 147(1): 257 - 271. [Abstract] [Full Text] [PDF] |
||||
![]() |
X. Ye, S. J. Han, S. Y. Tsai, F. J. DeMayo, J. Xu, M.-J. Tsai, and B. W. O'Malley Roles of steroid receptor coactivator (SRC)-1 and transcriptional intermediary factor (TIF) 2 in androgen receptor activity in mice PNAS, July 5, 2005; 102(27): 9487 - 9492. [Abstract] [Full Text] [PDF] |
||||
![]() |
K. A. L. Tan, K. De Gendt, N. Atanassova, M. Walker, R. M. Sharpe, P. T. K. Saunders, E. Denolet, and G. Verhoeven The Role of Androgens in Sertoli Cell Proliferation and Functional Maturation: Studies in Mice with Total or Sertoli Cell-Selective Ablation of the Androgen Receptor Endocrinology, June 1, 2005; 146(6): 2674 - 2683. [Abstract] [Full Text] [PDF] |
||||
![]() |
Q. Zhou, J. E. Shima, R. Nie, P. J. Friel, and M. D. Griswold Androgen-Regulated Transcripts in the Neonatal Mouse Testis as Determined Through Microarray Analysis Biol Reprod, April 1, 2005; 72(4): 1010 - 1019. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |