Endocrine function and regulation of the fetal and neonatal testis

An interesting sex difference prevails in the early development of endocrine functions in the ovary and testis. The testis actively produces androgens already in utero whereas the physiologically important steroid hormone production of the ovary does not start until puberty. Likewise, the different components of the hypothalamic-pituitary-gonadal axis seem to mature earlier in the male. The hormonal regulation of the fetal testes differs in many respects from that of the adult, and these differences make it possible for the fetal testes to function in the intrauterine endocrine milieu. The purpose of this review is to summarize our findings on the development, special functional characteristics and physiological role of the fetal and neonatal pituitary-gonadal axis.