The relationship between menstrual blood loss and prostaglandin production in the human: evidence for increased availability of arachidonic acid in women suffering from menorrhagia.

In this study we have obtained endometrium and myometrium from women whose menstrual blood loss had been measured objectively. Samples of tissue were snap frozen in liquid nitrogen for the estimation of PG content and tissue was homogenized and incubated with and without added arachidonic acid. PGE, PGF2 alpha and 6-oxo PGF1 alpha were measured by gas chromatography - mass spectometry. We confirm that the F2 alpha/E2 ratio in the snap frozen samples was significantly lower in women with a high blood loss although this was not reflected in the production by incubated homogenates. Incubation of endometrial tissue with myometrium from the same patient and with a pool of myometrium showed that the source of myometrium was not important. This suggests that previous observations of increased 6 oxo F1 alpha production in incubations of endometrium and homologous myometrium from women with high MBL, resulted from differences in endometrium. When prostaglandin E and F production by endometrium is studied there is a significant inverse correlation between the percentage difference in production with and without added arachidonic acid and menstrual blood loss which suggests that women with high MBL have relatively high levels of available arachidonic acid in their endometrium.