PHARMACOLOGIC STUDIES OF 15-METHYLPRO''STAGLANDIN F2a(PGF2a)

Some of the important pharmacologic ac- tions of 15-methyl PGF 2cc are reported in this paper. The potency of subcutaneous 15-methyl PGF 2a in terminating early pregnancy in mice is about 10 times greater than that of PGF 2aThis action can be suppressed by simultaneousadministration of either megestrol acetate or HCG. 15-methyl PGF2a can also shorten thepseudopregnancy period and inhibit the forma-tion of deciduoma. Experiments on isolatedsmooth muscles show that the contra.ctile ac- tivity of 15-methyl PGF2a on the uterine muscle is similar to that of PGF2a: . However, contrac- tile activity of 15 methyl-PGF 2a on isolated ratstomach fundus and rabbit jejunum are only300/o that of PGF2a. Acute toxicity tests onmonkeys show no observable toxic reactionsafter administration of 15-methyl PGF2a at thedoses used in this experiment.