Luteinizing Hormone Secretion by Male Rat Pituitary Cells Perifused In Vitro: Effect of Experimental Left Varicocele and Orchiectomy

It has been shown previously that experimental left varicocele in the rat, results in a bilateral decrease in intratesticular testosterone. In the present work, pituitary responsiveness to GnRH as a possible mediator of this effect has been examined. Unilateral varicoceles were created in adult rats. A second group of animals underwent a sham operation and a third underwent bilateral orchiectomy. Thirty days after surgery, rats from all three groups were sacrificed and their pituitaries were removed. Dispersed pituitary cells were perifused in Bio‐Gel columns with varying concentrations of GnRH. The concentration of LH in the collected eluent was determined by radioimmunoassay. The mean, overall GnRH‐stimulated LH immunoreactive secretion rate (ng/min/10⁷ cells) by pituitary cells from rats with varicocele (0.062 ± 0.11) was no different from the overall release from the sham‐operated controls (0.051 ± 0.007). The dose‐response curves for GnRH‐stimulated release of LH by dispersed pituitary cells in the two groups also were not different. The overall GnRH‐stimulated LH release by cells from the orchiectomized rats (0.171 ± 0.032) was significantly greater than release by cells from the sham‐operated and varicocele rats, and the concentration‐response curve from the orchiectomy group was significantly elevated over those of the other two groups. These results indicate that GnRH‐stimulated immunoreactive LH release is not altered in rats with experimental left varicocele and, thus, is not the source of an endocrinopathy that leads to decreased intratesticular testosterone concentrations in these animals. 1989 American Society of Andrology