SOMATOTROPIC AXIS AND BODY-WEIGHT IN PREMENOPAUSAL AND POSTMENOPAUSALWOMEN - EVIDENCE FOR A NEUROENDOCRINE DERANGEMENT, IN ABSENCE OF CHANGES OF INSULIN-LIKE-GROWTH-FACTOR BINDING-PROTEIN CONCENTRATIONS

The altered function of the somatotropic axis observed in perimenopaus e may underlie the changes in body weight and fat distribution, The ai m of the present study was to evaluate, in pre-menopausal and post-men opausal women with body mass index (BMI) greater than or equal to or < 25, the basal plasma levels of growth hormone (GH), insulin-like growt h factor (IGF)-I and -II, IGF binding protein (IGFBP)-1 and -3, and th e response of GH and IGFBP-1 and -3 to GH releasing hormone (GHRH) and GHRH plus arginine tests, GH and IGF-I basal concentrations were sign ificantly higher in pre-menopausal than in post-menopausal women, whil e IGF-II, IGFBP-1 and IGFBP-3 concentrations did not vary significantl y, IGFBP-1, but not IGFBP-3, concentrations were higher in lean than i n obese patients, Insulin concentrations were significantly higher in obese patients, while no differences were observed between pre-menepau sal and post-menopausal women, In all subjects, GH concentrations incr eased significantly during GHRH test; pre-menopausal and lean women sh owed a higher response compared to post-menopausal and obese women, Th e GHRH plus arginine test stimulated GH response in all women, irrespe ctive of age and BMI, IGFBP-1 and -3 concentrations did not vary in re sponse to GHRH or GHRH plus arginine tests, The somatotropic axis unde rgoes modifications in post-menopausal women, apparently not involving IGFBP-1 and -3, Arginine infusion restores the response of GH to GHRH , in both post-menopausal and obese subjects, A somatostatinergic hype ractivity at the climateric period may underlie the changes both in bo dy weight and somatotropic axis.