Effect of Suppression of Prolactin on Gonadal Function in Immature Male Hamsters/Der Einfluß der Prolaktinsuppression auf die Gonadenfunktion bei unreifen männlichen Hamstern

Effect of deprivation of endogenous follicle stimulating hormone on rat epididymis: a histological evaluation

The growth and function of the epididymis are regulated by testosterone produced by Leydig cells in the testes. In the present study it was observed that neutralization of endogenous follicle stimulating hormone (FSH) in immature rats using a highly specific antiserum to ovine FSH resulted in changes in the histology of the epididymis along with a decrease (50-60%) in its weight compared with the normal serum-treated controls. These changes were observed in both rat and monkey epididymis without any decrease in serum testosterone, on which epididymis is known to be dependent. A detailed study was therefore carried out on the effects of deprivation of FSH or testosterone on the histology of epididymis. The changes in epididymal histology following FSH deprivation included a decrease in the size of the tubule lumen in the rat as well as in the adult male bonnet monkey in which the antiserum against ovine FSH was raised. Intensive vacuolization and uneven surface of the luminal epithelium was also observed. In contrast, the effect of deprivation of testosterone support by way of administration of LH antiserum or fiutamide resulted in a decrease in the size of the lumen and degenerative changes. These results suggest that cauda epididymidis is a target for FSH action.

Effect of deprival of LH on Leydig cell proliferation: involvement of PCNA, cyclin D3 and IGF-1

The levels of proliferating cell nuclear antigen (PCNA) and cyclin D3 which are known markers of cellular proliferation were monitored by immunoblotting in progenitor Leydig cells (PLC), immature Leydig cells (ILC) and adult Leydig cells (ALC) isolated from 21, 35 and 90 day old rats, respectively which represent the Leydig cells at different stages of development. The levels of PCNA and cyclin D3 were highest in PLC, intermediate in ILC and lowest in ALC. Following administration of an antiserum to LH to deprive endogenous LH in 21 day old rats, a significant decrease in the levels of PCNA and Cyclin D3 were observed suggesting the involvement of Lutenizing hormone (LH) in PLC proliferation. In support of this observation, Bromodeoxyuridine (BrdU) incorporation was highest in PLC when compared with ILC and ALC, and administration of LH antiserum to 21 day old rats led to a total absence of BrdU incorporation by the isolated PLC. Also, there was a decrease in the level of IGF-1 and IGF-1 receptor mRNA levels by 55 and 35%, respectively as assessed by semi-quantitative RT-PCR. In addition, the PLC isolated from rats deprived of endogenous LH incorporated much less BrdU following addition of IGF-1. These results, which are obtained using an in vivo model system establish that LH has a very important role in Leydig cell proliferation in immature rats.