The Functional Significance of FSH in Spermatogenesis and the Control of Its Secretion in Male Primates

Abstract

The aim of this review is to provide an integrative analysis of the role of FSH in the control of testicular function in higher primates, including man. Attention is focused on the action of FSH during neonatal development, puberty, and adulthood. Whether FSH is the major determinant of the adult complement of Sertoli cells and whether FSH is obligatory for the initiation, maintenance, and restoration of spermatogenesis is evaluated. The mechanism whereby the circulating concentration of FSH regulates spermatogonial proliferation to dictate the sperm production rate under physiological conditions in the adult is discussed in detail. Inhibin B is the major component of the testicular negative feedback signal governing FSH beta gene expression and FSH secretion, and the evidence for this view is presented. The review concludes with the presentation of a model for the operation of the FSH-inhibin B feedback control system regulating sperm production postpubertally in monkey and man, and with speculation on issues of clinical interest.

Alteration of fertility endpoints in adult male F-344 rats by subchronic exposure to inhaled benzo(a)pyrene

“…Such a decrease could result in decreased intra-testicular androgen binding proteins. Androgen binding proteins are required for the maintenance of high concentrations of testosterone in the testis, a requirement for the maintenance of optimal spermatogenesis after its initiation by FSH (Plant and Marshall, 2001). A reduction in intra-testicular testosterone normally results in reduced spermatogenesis (Jeyaraj, 2005) and could explain the reduced density of stored spermatozoa among BaP-exposed rats in this study compared with controls.…”

“…This observation is most likely due to BaP-induced reduction in sperm numbers (Tate and Singh, 1981;Revel et al, 2001) transported into the epididymides post spermeation. According to Plant and Marshall (2001), high intratesticular testosterone concentration is required for the regulation of spermatogenesis, the reduction of which results in fewer matured sperm produced by the testis. Furthermore, the reduced concentrations of plasma testosterone among BaP-exposed rats compared with UNC may have caused a rapid regression in the epididymal epithelium, especially in the initial segment and the proximal caput epididymal region (Jones, 2004).…”

“…Our data show a decrease in the interstitial volume and weight in BaP-exposed versus UNC rat testis histological preparations, suggesting the loss of Leydig cells. Also, the reactive metabolites of BaP may have disrupted androgen function by reducing androgen receptor levels in testes (Plant and Marshall, 2001), particularly in Sertoli cells. Such a decrease could result in decreased intra-testicular androgen binding proteins.…”

Control of Spermatogenesis in Primate and Prospect of Male Contraception

“…Sertoli cells play an important role in spermatogenesis. Full Sertoli proliferation can be accomplished by FSH activity without LH requirement [47]. FSH is the major determinant of the adult complement of Sertoli cells and is obligatory for the initiation, maintenance and restoration of spermatogenesis [47].…”

“…Full Sertoli proliferation can be accomplished by FSH activity without LH requirement [47]. FSH is the major determinant of the adult complement of Sertoli cells and is obligatory for the initiation, maintenance and restoration of spermatogenesis [47]. FSH at the cellular level stimulated the cAMP-dependent activation of protein kinase A in Sertoli cells, but the molecular mechanism of FSH action on spermatogenesis is poorly understood [57].…”