Corticotropin- and lysine-vasopressin induced changes of plasma corticosteroids and testosterone in the adult male pig

Abstract

Intravenous injection of 10.0 μg/kg body weight synthetic corticotropin (^1-24 ACTH) into chronically cannulated boars resulted in significantly elevated plasma corticosteroid and testosterone levels between 20 and 140 min (corticosteroids) and 20–80 min (testosterone) after injection. Administration of lysine-vasopressin (LVP) at doses of 0.1, 0.2 and 0.4 IU/kg body weight elicited a significant increase of plasma corticosteroids between 20 and 40 min after injection; on the other hand, plasma testosterone concentrations tended to fall when compared to pre-treatment levels. From our results it can be concluded that exogenously applied ACTH can effectively stimulate the release of corticosteroids and testosterone. Intravenous administration of LVP results in significantly, although not maximally increased plasma corticosteroid concentrations; the release of endogenous ACTH induced by LVP injection, on the other hand, appeared to be too small to stimulate testosterone release significantly.