Endocrinology, Vol 126, 95-101, Copyright © 1990 by Endocrine Society

ARTICLES

To what extent can spermatogenesis be maintained in the hypophysectomized adult rat testis with exogenously administered testosterone?

R Santulli, RL Sprando, CA Awoniyi, LL Ewing and BR Zirkin
Department of Population Dynamics, School of Hygiene and Public Health, Johns Hopkins University, Baltimore, Maryland 21205.

In a previous study it was demonstrated that spermatogenesis can be maintained quantitatively with exogenously administered testosterone in adult intact rats that lack LH. The studies described herein were designed to examine the extent to which spermatogenesis can be maintained quantitatively with exogenously administered testosterone in adult rats that lack all pituitary hormones. Adult male rats were hypophysectomized and testosterone was administered at the time of hypophysectomy via sustained release polydimethylsiloxane (PDS) capsules of increasing lengths. We used the PDS capsules to clamp testosterone at defined concentrations within the seminiferous tubule fluid over a 2- to 3-month treatment period. Mean testis weights and advanced spermatid numbers per testis stabilized by 8 weeks of testosterone treatment regardless of testosterone dose. Both testis weight and advanced spermatid number responded to testosterone dose, reaching plateaus of 1.2 g and 170 x 10(6) per testis, respectively. These values were 60% of, and significantly less than, the respective control values. This result was in striking contrast to the results of our previous study of LH-suppressed intact rats, in which exogenously administered testosterone resulted in testis weights and advanced spermatid numbers that plateaued at values not significantly different from those in controls. These different effects of testosterone in intact and hypophysectomized rats occurred despite the fact that the seminiferous tubule fluid testosterone concentrations achieved in the hypophysectomized rats (up to 25 ng/ml) were greater than the minimal testosterone concentration found previously to be required to maintain spermatogenesis quantitatively in LH-suppressed intact rats (13 ng/ml). Taken together, these results demonstrate clearly that intratesticular testosterone doses that are as high as or higher than those that maintain spermatogenesis quantitatively in intact rats lacking LH fail to maintain spermatogenesis quantitatively in rats lacking all pituitary hormones.

This article has been cited by other articles:

				J. P. Jarow, W. W. Wright, T. R. Brown, X. Yan, and B. R. Zirkin Bioactivity of Androgens Within the Testes and Serum of Normal Men J Androl, May 1, 2005; 26(3): 343 - 348. [Abstract] [Full Text] [PDF]

				M. D. Show, M. D. Anway, and B. R. Zirkin An Ex Vivo Analysis of Sertoli Cell Actin Dynamics Following Gonadotropic Hormone Withdrawal J Androl, November 1, 2004; 25(6): 1013 - 1021. [Abstract] [Full Text] [PDF]

				M. D. Show, J. S. Folmer, M. D. Anway, and B. R. Zirkin Testicular Expression and Distribution of the Rat Bcl2 Modifying Factor in Response to Reduced Intratesticular Testosterone Biol Reprod, April 1, 2004; 70(4): 1153 - 1161. [Abstract] [Full Text] [PDF]

				H. F. S. Huang, S. Wang, C. A. Molina, and J. E. Ottenweller Preservation of Spermatogenesis in Spinal Cord Injured Rats With Exogenous Testosterone. Relationship With Serum Testosterone Levels and Cellular Localization of cAMP Responsive Element Modulator J Androl, January 1, 2004; 25(1): 95 - 103. [Abstract] [Full Text] [PDF]

				T. Yazawa, T. Yamamoto, Y. Jin, and S.-i. Abe Follicle-Stimulating Hormone Is Indispensable for the Last Spermatogonial Mitosis Preceding Meiosis Initiation in Newts (Cynops pyrrhogaster) Biol Reprod, January 1, 2002; 66(1): 14 - 20. [Abstract] [Full Text]

				J.-M. Kim, S. R. Ghosh, A. C. P. Weil, and B. R. Zirkin Caspase-3 and Caspase-Activated Deoxyribonuclease Are Associated with Testicular Germ Cell Apoptosis Resulting from Reduced Intratesticular Testosterone Endocrinology, September 1, 2001; 142(9): 3809 - 3816. [Abstract] [Full Text] [PDF]

				S. Maiti, J. Doskow, S. Li, R. P. Nhim, J. S. Lindsey, and M. F. Wilkinson The Pem Homeobox Gene. ANDROGEN-DEPENDENT AND -INDEPENDENT PROMOTERS AND TISSUE-SPECIFIC ALTERNATIVE RNA SPLICING J. Biol. Chem., July 19, 1996; 271(29): 17536 - 17546. [Abstract] [Full Text] [PDF]

				C. J. Bagatell and W. J. Bremner Androgens in Men -- Uses and Abuses N. Engl. J. Med., March 14, 1996; 334(11): 707 - 715. [Full Text] [PDF]