Prostaglandins: the once-a-month birth control pill of the future.

Prostaglandins (PGs)--naturally occurring fatty acids that are common to both humans and animals--possess a wide range of potent physiologic activities which have potential clinical application. The advent of PGs provided potentially safe, effective abortifacients and antifertility agents. It was not until the 1950s that research activity in PGs emerged from its dormant state. Prior to that period little was learned about the chemistry of PGs because only minute quantities are present in mammalian tissues. The great advances that were to take place awaited the development of sophisticated methods for isolation and structure determination of organic compounds. This culminated with the outstanding work of Dr. Bergstrom and his associates in Sweden who reported on the molecular structure of several PGs in the early 1960s. Due to the low concentrations of PGs in animal tissues, there was an extreme shortage of the pure material until about 1965 when biosynthetic methods for their production were devised. More recently, totally synthetic PGs have been prepared by Dr. E.J. Corey at Harvard. Thus far 14 PGs have been isolated and identified. They have been classified into subgroups A, B, E, and F according to their chemical structures. About 5 years ago, a pharmacologist interested in native medical folklore in Uganda, Dr. Karim, observed that Bantu native children born in the bush did not have their umbilical cord stumps tied and that bleeding was not a problem unless the infant was premature. He subsequently found that the umbilical cord, the amniotic fluid, and the venous blood of women during labor contained PGE2 and PGF2alpha, while they were either absent or in very low concentrations in patients who had undergone cesarean section without previous labor. Dr. Karim's more recent work has been concerned with the once-a-month vaginal administration of tablets containing E2 and F2alpha for fertility control. The mechanism by which PGE2 and PGF2alpha induce menstruation in humans has not been clarified as yet.