EFFECTS OF ANDROGENS ON ISOLATED RAT UTERUS

The 5alpha- and 5beta-dihydrotestosterone (DHT) androgens relax KCl-in duced tonic contraction in rat uterus, in a dose-dependent way. The 5a lpha and 5beta-DHT relaxing effect is counteracted by CaCl2 (0.1-10 mM ). The 5alpha-DHT, but not the 5beta-DHT, effect was reduced by cycloh eximide (10 mug/ml) and by actinomycin D (5 mug/ml). Flutamide at 10(- 6) M shifted the effect of 5alpha-DHT to the right. However, other dos es of flutamide or cyproterone acetate did not modify the effect of bo th androgens. We suggest a non-genomic effect of 5alpha-DHT and 5beta- DHT in rat uterus contraction but that intracellular and genomic actio ns play a part in the relaxing effect of 5alpha-DHT.