Reproductive steroids in white-tailed deer. IV. Origin of progesterone during pregnancy.

The primary source of progesterone during pregnancy in white-tailed deer (Odocoileus virginianus borealis) was examined in two experiments. Ovariectomy at 110 or 156 days of gestation reduced progesterone levels in jugular vein blood serum from 5.1 +/- 0.7 ng/ml to 0.3 +/- 0.1 ng/ml and resulted in termination of pregnancy. Sham-operated does maintained pregnancy and preoperative progesterone levels. Measured at 110 days gestation in three does, progesterone concentrations in ovarian vein, uterine artery and vein, and jugular vein blood serum averaged 319.3 +/- 29.3, 5.9 +/- 0.3, 46.7 +/- 8.9, and 4.9 +/- 0.4 ng/ml, respectively. Ovarian vein concentrations of progesterone fluctuated over a 2-3/4 h collection period between 70 and 1200 ng/ml. Uterine and jugular vein concentrations of progesterone fluctuated less dramatically. These experiments suggest that the ovaries are the principal source of progesterone through the first 156 days of the normal 200-day gestation in white-tailed deer and that the ovaries are essential for maintenance of pregnancy during this time.