TESTOSTERONE PRODUCTION IN FETAL TESTES OF THE SILVER FOX

Testosterone content was studied in fetal serum and testes of silver f oxes during different periods of prenatal life. The first sign of test osterone synthesis in the testes could be detected starting from the 3 1st day of gestation by radioimmunoassay. Subsequently its content sha rply increased and showed maximum value on the 50th day. Detectable se rum testosterone level in male silver fox fetus was noted from the 40t h day, its serum concentration increased in prenatal life, but only in significantly. Testicular production of testosterone was stimulated by hCG at the stages studied from Day 40 on. It is supposed that silver fox testes were able to respond to gonadotrophin not earlier than by D ay 40 of prenatal life, but the establishment of pituitary-testicular interrelationship was clearly demonstrated at the end of embryogenesis (Day 50).