Endometrial content of prostaglandin precursors during the menstrual cycle

Fractionated curettage was performed in 18 women with cervical intraepithelial neoplasia. Otherwise all appeared to be healthy. The histological examination showed 9 of them to have been sampled in the follicular phase and the other 9 in the luteal phase. Endometrial specimens were simultaneously taken for analysis of the fatty acid pattern of lecithin (PC) and phosphatidylethanolamine (PE) by means of gas-liquid chromatography (GLC). In the luteal phase we found increased concentrations of the total sum of essential fatty acids of the linoleic acid series both in PC and PE (p less than 0.01 in both cases). All the main fatty acid components within this series showed increased mean levels in the luteal phase but only arachidonic acid (20:4) in PE was significantly elevated (p less than 0.01). The total sum of the alpha-linolenic acid series was unaffected by the phase of menstrual cycle. These results seem to indicate that the endometrium accumulates prostaglandin precursors towards the time for menstruation.