title: The effects of ritodrine on prostaglandin metabolite concentrations in the blood of pregnant baboons.
abstract: To investigate the relationship between beta sympathomimetic drugs and prostaglandins, we measured prostaglandin metabolites in the plasma of pregnant baboons that were given the drug ritodrine. Animals were at a mean gestation of 120 days, which is equivalent to 27 weeks in women. Ritodrine was infused i.v. at a rate of 23 micrograms/min or 80 micrograms/min for 4 h. Plasma concentrations of 13,14-dihydro-15-keto-prostaglandin F2 alpha (PGFM), 11-deoxy-13,14-dihydro-15-keto-11,16-cyclo-prostaglandin E2 (PGEM-11), and 6-keto-prostaglandin-F1 alpha (6-keto-PGF1 alpha) were determined as indicators of the precursors, prostaglandin F2 alpha, prostaglandin E2, and prostacyclin (PGI2), respectively. At the 23 micrograms/min ritodrine infusion rate plasma levels of 6-keto-PGF1 alpha were decreased by 51% (+/- 15%) in the animals receiving the drug (p less than 0.005) whereas corresponding levels in control animals did not differ significantly from pre-infusion levels. At the 80 micrograms/min ritodrine infusion rate, the plasma levels of 6-keto-PGF1 alpha decreased by 66% (+/- 18%) compared with pre-infusion levels (p less than 0.001) but again the levels in control animals were not changed significantly. Plasma levels of PGFM and PGEM-11 in animals during ritodrine treatment did not differ significantly from baseline values.
mesh_terms: D000818:Animals; D011464:Epoprostenol / Q000097:blood*; D005260:Female; D010215:Papio; D011247:Pregnancy; D011412:Propanolamines / Q000494:pharmacology*; D011453:Prostaglandins / Q000097:blood* / Q000378:metabolism; D012312:Ritodrine / Q000494:pharmacology*
chemical_list: D011412:Propanolamines; D011453:Prostaglandins; D011464:Epoprostenol; D012312:Ritodrine