Local regulation of Leydig cells by the seminiferous tubules. Effect of short‐term cryptorchidism

Abstract

Unilateral cryptorchidism was induced in adult rats for 24 h, and its effect on testicular morphology and intratesticular testosterone concentration after hCG [human chorionic gonadotropin]-stimulation were studied. In seminiferous tubules from abdominal testes an increased number of degenerating germ cells was noted in stages XIV-III of the spermatogenic cycle, and Sertoli cells contained an increased amount of lipid droplets in stages XIV-VIII. Germ cells and Sertoli cells from tubules at other stages of the cycle appeared unaffected. In scrotal tests the size of peritubular Leydig cells varied in phase with the spermatogenic cycle. The largest cells were found adjacent to stage VII-VIII and the smallest adjacent to stage XI-XIII. In abdominal testes no stage-dependent variation in the size of peritubular Leydig cells was seen. Perivascular Leydig cells were of equal size in abdominal and scrotal testes. The testicular testosterone concentration following stimulation with a low dose of hCG was significantly lower in abdominal testes. Apparently the seminiferous tubules locally modulate Leydig cell function, and the stage-specific stimulatory influence from stage VII-VIII is rapidly lost during experimental cryptorchidism.