TRANSDERMAL 17-BETA-ESTRADIOL COMBINED WITH ORAL PROGESTOGEN INCREASES PLASMA-LEVELS OF INSULIN-LIKE GROWTH FACTOR-I IN POSTMENOPAUSAL WOMEN

In order to evaluate the effect of post-menopausal estrogen replacement therapy on the plasma levels of the insulin-like growth factor-I (IGF-I) 12 postmenopausal women aged 44 to 59 years were studied. The control group consisted of 15 healthy premenopausal women aged 20-44 years. In the postmenopausal women the plasma levels of IGF-I, gonadotrophins and sex hormones were determined before and after 3 and 6 months cyclic replacement therapy with transdermal 17-beta-estradiol (E2 100-mu-g patches applied twice weekly) combined with oral chlormadinone acetate (2 mg daily for 7 days in each cycle). Basal levels of estradiol (E2), IGF-I, dehydroepiandrosterone sulphate (DHEA-S), testosterone and androstenedione were lower, but gonadotropin levels were higher in postmenopausal than in premenopausal women. In all the women studied age was inversely correlated with IGF-I levels r(=-0.793, p<0.001) and with DHEA-S concentrations (r=-0.435, p<0.02). In postmenopausal women transdermal estradiol administration restored the circulating E2 levels to the early follicular range and increased the IGF-I levels (from 76.4+/-9.2-mu-g/l to 141.8+/-20.8-mu-g/l; p<0.01). Transdermal estradiol decreased gonadotrophin levels without changes in concentration of DHEA-S, testosterone, androstenedione and SHBG. In postmenopausal women before and during replacement therapy a positive correlation was found between estradiol and IGF-I concentrations (r=0.439, p<0.01). These results suggest that cyclic replacement therapy with transdermal 17-beta-estradiol in combination with chlormadinone acetate given orally increase the plasma levels of IGF-I in postmenopausal women.