The post-menopausal uterus: the effect of hormone replacement therapy on the serum levels of secretory endometrial protein PP14/beta-lactoglobulin homologue.

The effect of cyclical oestrogen-progestogen replacement on the levels of endometrial secretory protein PP14 (placental protein 14) was studied in 39 post-menopausal women, 13 of whom had had a hysterectomy. In those women with an intact uterus, the average rise of the late luteal phase serum PP14 concentration was from 29 to 45 micrograms/l, a 55% rise (P less than 0.001). Only a slight rise (from 27 to 30 micrograms/l) was observed in hysterectomized women. Cyclical replacement with oestrogen and levonorgestrel caused a greater rise in serum PP14 level than did replacement with the same dose of oestrogen plus medroxyprogesterone acetate (P less than 0.05). Because PP14 is found also in the serum of hysterectomized post-menopausal women, the uterus cannot be the only source of circulating PP14. But, the difference between hysterectomized and non-hysterectomized women indicates that the quiescent post-menopausal uterus responds to oestrogen-progestogen replacement by increased PP14 secretion, which can be detected and quantified by a blood test. The measurement of PP14 in serum may also become useful for testing the effect of various progestogens.