Sex steroids levels in the plasma and testis during the reproductive cycle of lizard Podarcis s. sicula raf

Progesterone (P), 17-OH-progesterone (17-OH-P), androstenedione (A), dehydroepiandrosterone (DHEA), testosterone (T), 5α-dihydrotestosterone (5α-DHT), and 17β-estradiol (E 2) were measured by RIA in plasma and testes of 114 males of the oviparous lizard Podarcis s. sicula raf, a species that displays annual hibernating cycles. Hormones were determined each month from January until December, except for August. Testosterone peaked at 174.8 ng/ml of plasma after emergence (March), while 5α-DHT and A peaked in April. Plasma DHEA increased during hibernation. During the refractory period there were progressive increases in P and E 2 plasma levels. The testicular peak of T, in March, coincided with that observed in plasma. The striking increases in testicular T and A in early July occurred at a time when plasma androgen concentrations were low. 5α-DHT increased in April when spermatogenesis with spermiation occurred and then decreased alongside a second peak of T. There is an apparent separation of plasma and testicular androgen concentrations during the reproductive cycle.