[The role of dehydroepiandrosterone and pregnenolone in the expression of stress behavior towards lactating females in mice].

Triads of castrated male mice were chronically administered with either oil vehicle or 280 nmol of dehydroepiandrosterone (D) or pregnenolone (P). They were tested for their attack on a lactating intruder female introduced in their home-cage 2, 24 or 47 hr after their last injection. D significantly reduced male aggressive behavior for at least 24 hr. Other groups of castrated males were daily treated with vehicle or 280 nmol of D, dehydroepiandrosterone sulfate (DS) or androstenediol (ADIOL), a D metabolite with clear-cut oestrogenic properties. D, but neither DS nor ADIOL, significantly reduced their aggressive responses to lactating intruders. Finally, neural levels of D, DS and testosterone (T) were measured in intact and castrated males injected with either vehicle or D. Measurable amounts of D and DS were detected, with DS being the predominant chemical form. D and DS concentrations were unchanged by castration but neural D was increased more than twenty fold in castrates treated with D, whereas DS was unchanged. The concentration of T in the brain of the intact (sham-operated) mouse approached 3 ng/g but fell close to the detection limit after gonadectomy. D treatment caused a slight but significant increase in brain T concentration in castrated mice, although T remained far below the level measured in intact males.