Levels of prostaglandins in human endometrium during the normal menstrual cycle

The levels of prostaglandins in the human endometrium throughout the normal menstrual cycle were measured by bioassay. The identity of prostaglandin F2alpha and prostaglandin E2 in endometrial tissue extracts was established by combined gas chromatography/mass spectrometry. The levels of prostaglandin F2alpha and prostaglandin E2 are low during the proliferative phase of the cycle (10-25 ng/100 mg tissue). Prostaglandin F2alpha rises significantly during the luteal phase to levels of 65-75 ng/100 mg of tissue. Prostaglandin E2 levels are similar to prostaglandin F2alpha levels in the proliferative phase but remain lower during the luteal phase. The prostaglandin E2 level is highest at menstruation (52 ng/100 mg tissue). The implications of these findings are discussed in relation to the menstrual process and to the steroid hormonal changes during the cycle.