IS CORTICOSTERONE INVOLVED IN THE REPRODUCTIVE PROCESSES OF THE MALE LIZARD, PODARCIS-SICULA-SICULA

Corticosterone (B) and testosterone (T) plasma levels and the effects of short (1-48 min) and long (6-192 hr) confinement stress during the various phases of the reproductive period of the male lizard, Podarcis sicula sicula, were studied; in addition, the in vitro effects of B o n the T secretion by testis and adrenals were evaluated. Plasma B was highest during the mating phase and plasma T was highest during the ag gressive phase. Confinement stress caused an increase of B plasma leve ls within 12 min of capture and a decrease in plasma T within 48 min o f capture; B increase and T decrease continued for 48 hr, but, after 1 92 hr of confinement, the levels of these two steroids became similar to those found a few minutes after capture. The basal release of T by the testes and of B and T by adrenals mirrored the trends seen in the systemic circulation. In in vitro experiments B treatment decreased T by testis and adrenal tissue release in aggressive and mating phases. These data suggest that B could involved in the reproduction of P. s. sicula by acting on T synthesis to reduce aggressive behavior and allo w breeding. (C) 1994 Academic Press, Inc.