Administration of extra-amniotic arachidonic acid and the suppression of uterine prostaglandin synthesis during pregnancy in the rhesus monkey.

After extra-amniotic treatment of pregnant rhesus monkeys premature parturition was induced in 4 given 2.5 mg PGE-2; none of the 4 monkeys given 100 mg arachidonic acid were affected. The concentrations of PGE, PGF, or 13,14-dihydro-15-oxo-PGF did not change after arachidonic acid treatment, but all increased after PGE-2. It is suggested that the availability of substrate, arachidonic acid, is not a major factor governing the control of PG synthesis but that the latter is suppressed during pregnancy.