The reproductive cycle in the male hedgehog (Erinaceus europaeus L.): a study of endocrine and exocrine testicular functions.

Seasonal changes in testicular and accessory gland weights, histological testicular structures, fructose and citric acid concentrations in two accessory glands and plasma testosterone levels were determined in adult male hedgehogs living in middle western France. Testicular activity started in winter (from December to February) during the last part of the hibernation period. During this resumption period, testis weights as well as all the testicular structural features (Leydig cell volume; length, diameter and volume of seminiterous tubules) increased. These changes were correlated with similar variations in plasma testosterone concentrations and accessory gland features (weight, fructose and citric acid contents). However, maximal development of endocrine testicular function was reached about one month before the completion of spermatogenesis and the maximal development of androgen target organs. Testicular activity was high from February-March to August-September, according to the year. After the spring peak corresponding to the main breeding period, a decrease in testicular activity was always noted in May-June. The values of the testicular features then remained high or increased again and a second breeding period always occurred. Finally, involution began at the end of summer but the endocrine function of the testis decreased before the exocrine function. All the gonadal functions were depressed from September to November. Our results show that in middle western France, one of the southern-most countries characterized by a mild, temperate climate, the testis of Erinaceus europaeus L. is activated earlier and the breeding season lasts longer than in any of the other European countries cited in the literature.