RESUMEN
The concentrations of plasma B-endorphin and serum prolactin, progesterone, estradiol and cortisol in 14 women complaining of premenstrual tension syndrome [P.M.S] and 14 normal women were measured at 25th day of the cycle followed by endometrial biopsy using Novak curette. There was significant elevation in prolactin and significant reduction in B-endorphin levels in cases of P.M.S. when P.M. S patients were classified according to prolactin level, hyper-prolactinaemic patients [serum prolactin > 20 ng/ml] had significantly higher level of B-endorphin compared to norm oprolactinaemic patients P < 0.01, while according to endometrial pattern, patients with luteal phase defect showed significant elevation of prolactin and B-endorphin compared to cases with normal secretory activity pattern. Nevertheless at all circumstances B-endorphin levels in P.M.S patients were significantly lower than normal. It is included from this study that, B-endorphin depletion can be considered, as a marker of P.M.S. and it may have an etiological effect on it