Hepatic metabolism of orally administered prostaglandin F_2α in suckling and weanling rats

Suckling (12- to 14-day-old) and weanling (30-day-old) rats were sacrificed 2 h after oral administration of ³H-labeled prostaglandin F_2α. Although radioactivity recovered from the stomach and small intestine (including contents) was slightly higher in sucklings (28.3 ± 3.7%; n = 10) than in weanling rats (21.3 ± 5.3%; n = 7), the liver of sucklings contained significantly higher amounts of counts (11.0 ± 1.1 vs. 3.3 ± 0.5%). Combined column and thin-layer chromatography of liver extracts showed more authentic prostaglandin F2ain sucklings (11.0 ± 0.5% of the liver counts) than in weanlings (7.0 ± 1.1%). The liver of suckling rats contained a higher percentage of more polar metabolites (43.3 ± 1.6 vs. 34.3 ± 3.0%). These studies demonstrate differences in processing of oral prostaglandin F_2α in the early postnatal period.