Glucose Metabolism, Lipid Metabolism, and Cardiovascular Risk Factors in Adult Turner's Syndrome: The impact of sex hormone replacement

Abstract

OBJECTIVE To examine glucose metabolism, blood pressure, physical fitness, and lipid metabolism in adult untreated women with Turner's syndrome compared with a group of normal women and to examine the effects of female sex hormone substitution on these factors. RESEARCH DESIGN AND METHODS A total of 26 patients with Turner's syndrome were examined before and during sex hormone replacement with 17β-estradiol and norethisterone, and an age-matched control group (n = 24) was examined once. A frequently sampled intravenous glucose tolerance test was applied with minimal model assessment. We also performed an oral glucose tolerance test, measurement of 24-h ambulatory blood pressure, and assessment of physical fitness and lipid metabolism. RESULTS Insulin sensitivity (SI) and glucose effectiveness (SG) were similar in Turner's syndrome patients and control subjects, whereas the acute insulin response (P = 0.03) was lower in Turner's syndrome patients, and no change was seen during sex hormone treatment. Abnormal glucose tolerance was found in 50% of Turner's syndrome patients before and 78% during treatment with sex hormones. Fat-free mass (FFM; P = 0.0005) and physical fitness (P = 0.002) were lower in Turner=s syndrome subjects compared with control subjects. During treatment, an increase in FFM (P = 0.001) and physical fitness (P = 0.02) was seen in Turner's syndrome patients. Blood pressure was increased in Turner's syndrome, and a decrease was seen in diastolic blood pressure during treatment with sex hormones. CONCLUSIONS Turner's syndrome is associated with glucose intolerance, diminished first-phase insulin response, elevated blood pressure, reduced FFM, and physical fitness. Sex hormone administration causes a deterioration in glucose tolerance, increases FFM and physical fitness, and has beneficial effects on blood pressure. The deleterious effect on glucose tolerance may be mediated by norethisterone, a gestagen known to have androgenic effects.