An endocrine and histophysiological study of the testicular annual cycle in the hedgehog ( Erinaceus europaeus L.)

Abstract

The histophysiology of the testis was studied all year round in adult male hedgehogs living in middle-western France. Variations in Leydig and Sertoli cell populations were correlated to plasma testosterone levels and compared to variations in seminiferous tubule diameter and germ cell production. During the last part of the hibernating period, in winter, Leydig cell parameters and plasma testosterone levels increased and reached maximum values in February, 1 month before the maximum development of seminiferous epithelium. The numerous large-sized Leydig cells in spring and summer corresponded to the maximum levels of plasma testosterone and maximum development of seminiferous tubules, spermatogenesis, and Sertoli cells. Regression occurred in August for Leydig cells and plasma testosterone levels, in September for seminiferous tubules and spermatogenesis. All the gonadal functions remained depressed from September to November. The relative frequency of the stages and duration of the seminiferous epithelium cycle were also studied. The same duration (10 days) was observed in hibernating animals in winter and active animals in spring.