Persistence of dihydrotestosterone inhibition of lordosis in estrogen-primed rats fed a tryptophan-deficient diet.

Administering increasing dosages of 5alpha-dihydrotestosterone propionate (DHTP) (0, 40, or 80 microgram/100 g in oil daily) to ovariectomized female rats treated concurrently with estradiol benzoate (EB) (1 microgram/100 g in oil daily) caused significant, equivalent reduction in lordotic responsiveness in rats maintained either on a tryptophan-deficient corn diet or on a corn diet to which L-tryptophan was added. Whole brain concentrations of 5-hydroxytryptamine (5-HT) and of 5-hydroxyindoleacetic acid were approximately two times higher in rats fed corn+tryptophan versus corn alone. These findings suggest that the ability of DHTP to inhibit lordosis probably depends upon some mechanism other than a facilitation of 5HT release from serotonergic neurons.