Serum levels of progesterone, estradiol, and hydrocortisone in ewes after abortion due to Listeria monocytogenes type 5.

Estradiol, progesterone, and hydrocortisone were measured by radioimmunoassay in peripheral serum of pregnant ewes infected with Listeria monocytogenes type 5 and in normal pregnant controls. Progesterone had decreased in both groups at abortion or parturition. Estradiol and hydrocortisone of control ewes had increased at parturition. In infected ewes, the serum hydrocortisone value was high for 3 days after inoculation, but it returned to preinoculation levels for the remainder of gestation. Serum concentrations of hydrocortisone did not change, and estradiol values increased slightly at abortion by infected ewes.