leptin and Klinefelter-Syndrome

Since little is known about the effects of gonadotropin and testosterone treatment on leptin levels in male hypogonadism, we determined fasting plasma leptin levels before and 3 months after treatment in 21 patients with idiopathic hypogonadotropic hypogonadism (IHH), 16 patients with Klinefelter's syndrome and 20 male controls. Patients with IHH were treated with hCG/human menopausal gonadotropin, whereas patients with Klinefelter's syndrome received T treatment. Plasma leptin levels were measured by an RIA with a sensitivity of 0.5 microg/L. Mean leptin levels in patients with IHH before treatment (9.23+/-4.09 microg/L) were not significantly different from those in patients with Klinefelter's syndrome (7.29+/-5.05 microg/L; z=-1.41; P=0.15). Leptin levels in both IHH and Klinefelter's syndrome groups were, however, significantly higher than in the normal men (3.91+/-1.67 microg/L) (P<0.001 and P<0.01, respectively). Mean leptin levels did not change significantly 3 months after the initiation of gonadotropin (11.6+/-6.44 microg/L) or T (8.32+/-5.17 microg/L) treatment in either IHH or Klinefelter's syndrome. Our study demonstrated that mean plasma leptin levels are not influenced by short-term gonadotropin or T treatment in male hypogonadism.

Topics: Adult; Chorionic Gonadotropin; Follicle Stimulating Hormone; Humans; Klinefelter Syndrome; Leptin; Luteinizing Hormone; Male; Prolactin; Proteins; Testis; Testosterone

Testosterone (T)-substitution therapy is widely used in adult patients with Klinefelter syndrome (KS) to prevent symptoms and sequels of androgen deficiency, but it is currently unknown if adolescent boys with KS benefit from early T therapy. To evaluate the optimal age to start T substitution, we searched for signs of androgen deficiency in pubertal boys with KS. 14 nonmosaic 47,XXY boys, aged 10-13.9 y, were followed up for 4-37 mo with staging of puberty and frequent reproductive hormone measurements. Furthermore, indices reflecting androgen action (serum SHBG, leptin, and prostate-specific antigen (PSA) levels) were studied. Both onset and progression of puberty according to Tanner stages were normal in boys with KS. Consistently, serum T concentrations increased as expected and remained normal throughout follow-up. Changes in the indices of androgen action (decreases in serum SHBG and leptin, and increase in serum PSA concentrations) occurred normally, except that average leptin levels were higher in the boys with KS (KS boys 11.8 +/- 7.0 microg/L; controls 7.6 +/- 4.7 microg/L; p = 0.033). Despite normal T concentrations, the KS boys displayed from the age of 13 y elevated serum FSH and LH levels, and exaggerated gonadotropin responses to gonadotropin-releasing hormone. These data do not demonstrate an unequivocal androgen deficiency in adolescent boys with KS that would necessitate androgen supplementation therapy during early puberty.

Topics: Adolescent; Androgens; Follicle Stimulating Hormone; Gonadotropin-Releasing Hormone; Humans; Karyotyping; Klinefelter Syndrome; Leptin; Luteinizing Hormone; Prospective Studies; Prostate-Specific Antigen; Puberty; Sex Hormone-Binding Globulin; Testosterone