LH contamination may explain FSH effects on rat Leydig cells

Abstract

Treatment of immature, hypophysectomized male rats with 50 micrograms ovine FSH (NIH-FSH-S12) twice a day for 5 days stimulated the maximum quantity of 17 beta-hydroxyandrogen produced by isolated Leydig cells in response to hCG. Pretreatment of the FSH preparation with an LH antiserum in one study markedly reduced and in another study completely abolished this stimulatory effect of FSH, but only slightly impaired the capacity of the hormone to stimulate the Sertoli cell in vivo (epididymal androgen-binding protein). Administration of another highly potent FSH preparation (LER-1881) had no discernible effects on the dose-response characteristics of the Leydig cells but was superior to the NIH-FSH-S12 in its capacity for stimulating the Sertoli cell. When all hormone preparations were tested for their ability to stimulate steroid secretion from normal Leydig cells in vitro, a close correlation was obtained between their Leydig cell-stimulating activity (a measure of LH contamination) and their capacity to alter Leydig cell responsiveness after in-vivo treatment. FSH treatment had no effects on specific LH binding per 10(6) Leydig cells. It is concluded that the stimulatory influence of FSH on rat Leydig cells may to some extent be a result of the LH contaminating the hormone preparation.

Effects of pure FSH and LH preparations on the number and function of Leydig cells in immature hypophysectomized rats

“…Although many observations indicate that FSH may have indirect effects on Leydig cells, Purvis et al (1979) reported that the stimulatory effect of FSH on Leydig cell responsiveness in hypophysectomized immature rats was completely prevented after pre¬ treatment of ovine FSH with an antiserum against LH. During the purification process, the FSH prep¬ aration used in our study was also pretreated with an antiserum against pLH (Closset & Hennen, 1988).…”

“…Evidence for this was presented by Purvis, Clausen & Hansson (1979), who showed that the stimulatory effect of FSH treatment on Leydig cell responsive¬ ness in hypophysectomized immature rats could be completely abolished if the FSH preparation was pretreated with an LH antiserum.…”

Evaluation of relative roles of LH and FSH in regulation of differentiation of Leydig cells using an ethane 1,2-dimethylsulfonate-treated adult rat model

“…Also, experimental induction of hypothyroidism led to an increase in Sertoli cells associated with a parallel increase in Leydig cells, thereby maintaining the ratio of Leydig cells to Sertoli cells constant (Cooke et al 1992). Studies by administering FSH have also shown a stimulatory role in Leydig cell function, but the physiological importance of these findings is a matter of debate, since most of the preparations of FSH used for the study were contaminated with LH and hence the observed effects could be attributed to the trace quantity of LH that was present in the FSH preparation (Purvis et al 1979, Moger & Murphy 1982, Lecerf et al 1993, Saez & Lejeune 1996. However, using recombinant FSH preparations, a role for FSH in regulation of Leydig cell function was demonstrated.…”

Localization of Luteinizing Hormone, Follicle-Stimulating Hormone, Prolactin, and Their Receptors in Human and Rat Testis Using Immunohistochemistry and Radioreceptor Assay*

“…It also increases the number of LH receptors on the Leydig cells and Leydig cell sensitivity to LH stimulation (13)(14)(15). Whereas the above studies imply direct actions of FSH on the interstitial tissue, contamination of FSH preparations with LH (16) has been suggested to explain some of the controversial findings. PRL has a permissive role in the induction of Leydig cell LH receptors in the rat testis (17,18).…”