Effect of in vivo prostaglandin treatment on 3H-PGF2alpha uptake in hamster corpora lutea.

Pregnant hamsters were administered (SC) prostaglandin or vehicle on the morning of the 4th day of pregnancy. Serum progesterone was significantly depressed (p less than .01) at 0.5, 2, and 6 hours after treatment with 100 microgram PGF2alpha. Serum progesterone levels were unchanged 2 hours and 6 hours after treatment with 100 microgram PGF2beta and 2 hours after treatment with 1 mg PGF2beta. Progesterone levels were depressed to less than 1 ng/ml 6 hours after treatment with 1 mg PGF2beta. The specific uptake of 3H-PGF2alpha in whole hamster corpora lutea was significantly depressed 2 hours and 6 hours following 100 microgram PGF2alpha treatment. A 15% depression in specific uptake occurred 0.5 hour post-treatment. Treatment with 100 microgram PGF2beta resulted in no change. Administration of 1 mg PGF2beta resulted in depressed 3H-PGF2alpha uptake at both 2 and 6 hours post-treatment. Prostacyclin (PGI2) treatment resulted in no change in either 3H-PGF2alpha specific uptake or serum progesterone 2 hours after 100 microgram treatment SC. These parameters were both reduced approximately 30% 6 hours post-treatment. Treatment with 6-keto-PGF1alpha resulted in a complete lack of measurable 3H-PGF2alpha uptake and serum progesterone levels less than 1 ng/ml at both 2 and 6 hours after treatment with 1 mg SC.