EFFECT OF NATURAL MENOPAUSE ON SERUM LEVELS OF IGF-I AND IGF-BINDING PROTEINS - RELATIONSHIP WITH BONE-MINERAL DENSITY AND LIPID-METABOLISMIN PERIMENOPAUSAL WOMEN

The present study was performed to examine the effect of natural menop ause on serum levels of IGF-I, IGF-binding protein (IGFBP)-2 and -3 as well as on bone mass and lipid metabolism in perimenopausal women. On e hundred and twenty-one healthy Japanese women, who were 45-55 years old, were studied (71 premenopausal and 50 postmenopausal women 1-9 ye ars after menopause). Bone mineral density (BMD) was measured at the m iddle third of the radius by using dual energy X-ray absorptiometry. S erum levels of IGF-I, but not those of IGFBP-2 or -3, were significant ly reduced in the postmenopausal group compared with the premenopausal group. One year after menopause, serum IGF-I levels were significantl y lower, and the biochemical markers of bone turnover such as serum to tal alkaline phosphatase level and urinary calcium to creatinine ratio , were significantly higher than the premenopausal levels. Serum level s of IGF-I, but not those of IGFBP-2 or -3, were positively correlated with BMD. Serum levels of IGFBP-2, but not those of IGF-I or IGFBP-3, were negatively correlated with body mass index and body weight. Fina lly, serum levels of IGFBP-3, but not those of IGF-I, were positively correlated with serum levels of total cholesterol and triglyceride, Th e present findings suggest that a rapid decrease in serum IGF-I levels after menopause might be partly involved in bone loss following gonad al failure and that IGFBP-2, and -3 might be related to the regulation of body mass and lipid metabolism during perimenopause respectively, although the mechanisms remain unknown.