Hormonal Regulation of Plasminogen Activator in Rat and Mouse Seminiferous Epithelium

Abstract

To elucidate the possible role of plasminogen activator (PA) in spermatogenesis and spermiation in mammals, we studied the hormonal regulation of PA secretion in cultured rat and mouse seminiferous tubules during defined stages of spermatogenesis. Results indicated that: (1) under basal conditions, segments of rat seminiferous tubules released primarily urokinase-type PA (uPA) at all stages of the cycle. The highest level of PA secretion occurred at stages VIIab, VIIcd and VIII. FSH, 8-bromo cyclic AMP and forskolin (FK) stimulated PA secretion, predominantly tissue-type PA (tPA). (2) In contrast, mouse seminiferous tubules secreted only tPA under basal conditions. In the presence of 50 µM MIX, seminiferous tubules at stages VII and VTII secreted higher levels of both types of PA than at the other stages. Both tPA and uPA secretion was enhanced by addition of FSH and FK to the organ culture media. (3) Segments of both rat and mouse seminiferous tubules at stages IX-XII in which the sperm residual bodies are absorbed into the Sertoli cells were also very sensitive to the addition of FSH to the organ culture. These results suggest that tPA in rat and mouse testes may play an essential role in the process of spermatogenesis and spermiation as well as in sperm residual body absorption.

Single-chain Tissue-type Plasminogen Activator Is a Substrate of Mouse Glandular Kallikrein 24

“…At a higher magnification, the staining signals were found to be localized to the area where Sertoli cells reside (Fig. 3C, arrows in the middle panel); this observation was consistent with the notion that tPA is synthesized in and secreted from Sertoli cells in the mouse testis (Lacroix et al, 1977;Vihko et al, 1984a;Vihko et al, 1984b;Liu et al, 1995;Tolli et al, 1995;Zhang et al, 1997;Gunnarsson et al, 1999). In addition, a clear signal was detected in the interstitial space of the testis (Fig.…”

Testosterone upregulation of tissue type plasminogen activator expression in Sertoli cells

“…They have different catalytic and antigenic properties and are encoded by two distinct genes [17], but share ability to cleave plasminogen to form active protease plasmin. It has been reported that low level of uPA activity was detected under basal condition in cultured Sertoli cells, whereas tPA activity was induced in a large amount in response to FSH stimulation [18][19][20][21]. PAI-1 is a primary physiologic inhibitor of naturally occurring plasminogen activators [22,23], known to form an SDS-stable complex with tPA [24].…”

“…Due to their stage-specific production and their different regulation by gonadotropins [18][19][20] and cell-cell interactions [25], it has been suggested that PA in seminiferous epithelium might play a role in tissue remodeling and cell migration which take place during release of preleptotene spermatocytes from basement membrane [26] and opening tight junctions between neighboring Sertoli cells allowing migration of zygotene spermatocytes to adluminal compartment of seminiferous epithelium [27]. PA system may also play a role in process of spermiation [28], the detachment of residual bodies from the mature spermatids [29], and the residual body phagocytosis by Sertoli cells [30].…”

Control of Spermatogenesis in Primate and Prospect of Male Contraception

“…Sertoli cells in mouse, rat and rhesus monkey produced plasminogen activators under the control of FSH in a spermatogenesis stage dependent manner [30]. The activator activity in the Sertoli cells increases greatly at stages VII-VIII when germ cell meiosis took place, and at the stage IX-XII when spermiation occurred in the Sertoli cells [30,31].…”

“…The activator activity in the Sertoli cells increases greatly at stages VII-VIII when germ cell meiosis took place, and at the stage IX-XII when spermiation occurred in the Sertoli cells [30,31]. This suggests that plasminogen activators regulated by FSH may be involved in the processes of spermatogenesis and spermiation in the Sertoli cells [29][30][31][32][33].…”