Stress-induced inhibition of reproduction: evidence of suppressed secretion of LH-RH in an amphibian.

Male rough-skinned newts (Taricha granulosa) were used to investigate the hormonal responses associated with stress-induced inhibition of reproduction. When male newts were confined for 1 hr, using a procedure that previously had elicited physiological stress responses, androgen concentrations decreased in the plasma and immunoreactive (ir) LH-RH concentrations increased in the infundibulum and rostral hypothalamus. Likewise, when male newts were injected with 25 micrograms of corticosterone, androgen concentrations decreased and hypothalamic irLH-RH concentrations increased. These data, which are from experiments in February, support the hypothesis that in this amphibian, exposure to acute stress or to exogenous corticosterone can suppress plasma androgen titers by inhibiting the release of LH-RH from the hypothalamus. The effects of the confinement procedure and the injection of corticosterone on the concentrations of irLH-RH and androgens were different for newts in September than for newts in February.