Concentrations of progesterone, 17 -hydroxyprogesterone and 20 -dihydroprogesterone in the plasma of mares during pregnancy and at parturition

Abstract

Plasma concentrations of progesterone and 17.alpha.-hydroprogesterone were high in the 2nd and 3rd mo. of gestation, but 20.alpha.-dihydroprogesterone increased from a level of 2 ng/ml, during the first 3 mo., to 10-15 ng/ml during mo. 5-10, to reach 80-120 ng/ml during the last 30 days before foaling.