HORMONAL REPLACEMENT THERAPY AFFECTS CALCITONIN-GENE-RELATED PEPTIDE AND ATRIAL-NATRIURETIC-PEPTIDE SECRETION IN POSTMENOPAUSAL WOMEN

Objective: Menopause is associated with critical changes in the cardio vascular system, and the possible effect of hormonal replacement thera py (HRT) on these changes is under investigation. The aim of our study was to evaluate in postmenopausal women the effects of HRT and clonid ine on the response of plasma calcitonin gene-related peptide (CGRP) a nd plasma atrial natriuretic peptide (ANP) to the upright posture test and the saline infusion test respectively. Methods: CGRP and ANP leve ls were measured with specific radioimmunological assays and expressed in pmol/l (means+/-S.E.M). Design: Postmenopausal women (age 46-53 ye ars) (n=18) were studied before and after 3 months of HRT (n=13) or cl onidine treatment (n=5). Results: After HRT or clonidine treatment pla sma CGRP levels (14.9+/-1.6 and 15.9+3.8 pmol/l) were significantly hi gher than before (9.8+0.6 and 10.5+/-1.6 pmol/l) (P<0.01). The assumpt ion of upright posture caused no change in plasma CGRP levels before t reatment, while after HRT, but not after clonidine treatment, an incre ase in plasma CGRP levels was observed (P<0.01 at 5 and 20 min). Basal plasma ANP levels significantly decreased after both HRT and clonidin e treatment (P<0.01). In untreated women the saline infusion test did not induce any change in plasma ANP levels; a significant response to the test was restored after HRT but not after clonidine treatment (P<0 .01 at 90 and 120 min). Conclusions: The results show that some of the adaptive responses modified by menopausal changes are restored by HRT but not clonidine treatment, suggesting a modulatory role for sex ste roid hormones in cardiovascular function and salt and water balance.