Effect of experimental left vericocele on rat leydig cell function

Abstract

In order to study endocrinological disorders in varicocele, serum hormone (LH, FSH and testosterone) levels, intratesticular temperature, and testicular histology were evaluated in the rats with experimental left varicocele. Testosterone production and its responsiveness to human chorionic gonadotropin (hCG) in isolated Leydig cells were also determined in the model. The varicocele was created by partial ligation of the left renal vein. The mean difference between intratesticular and intraperitoneal temperature and the levels of serum hormones were similar in varicocele-induced and sham-operated rats at either 2 or 4 weeks after surgery. Histological examination using the Johnsen score count method showed defective spermatogenesis at 2 and 4 weeks. In Leydig cell incubation, testosterone levels in the media without hCG were similar in the left testes of varicocele-induced rats (LV), the right testes of varicocele-induced rats (RV), and the testes of sham-operated rats (S) at 2 and 4 weeks. Although the presence of various concentrations of hCG made no difference in testosterone production between LV, RV, and S at 2 weeks, there were significantly decreased elevations in the production at 100 mIU/ml and 1,000 mIU/ml of hCG in LV and RV as compared with that of S at 4 weeks. The bindings of [125I] hCG to Leydig cells from LV and RV were significantly lower than S at 4 weeks. Furthermore, testosterone responsiveness to dibutyryl c-AMP in Leydig cells was similar between LV, RV, and S. These data indicate that experimental left varicocele in rats impairs the responsiveness of Leydig cells to hCG through a reduction in the number of hCG receptors, and this change does not seem to be caused by a rise in intratesticular temparature. Besides, it is suggested that defective spermatogenesis observed in this model is not subsequent to the endocrinopathy. © 1995, THE JAPANESE UROLOGICAL ASSOCIATION. All rights reserved.