Association of hyperthyroidism with serum leptin levels.
The present study was undertaken to determine whether thyroid hormones affect serum leptin levels in patients with hyperthyroidism. In 32 female patients with hyperthyroidism and 30 body mass index (BMI)-matched control subjects, there was no difference in serum leptin concentrations (9.0+/-1.0 v 8.2+/-0.9 microg/L). The serum leptin levels were compared with the expected values for serum leptin derived from the corresponding BMI with the formula for the control subjects (serum leptin [micrograms per liter] = 0.976 x BMI [kilograms per square meter] - 11.933, P < .001) and are expressed as the percent deviation (%leptin). There was a weak but significant positive correlation between serum free thyroxine (T4) levels and %leptin in the combined analysis of patients with hyperthyroidism and control subjects (r = .28, P < .05). Multiple regression analysis also revealed the independent contribution of free T4 levels to serum leptin. Antithyroid therapy ameliorated the hyperthyroidism and increased the BMI by 7.8% and the percent body fat by 9.9% in a subgroup of 21 patients with hyperthyroidism. However, serum leptin levels did not change during the 2-month therapeutic period (from 9.8+/-1.4 to 8.7+/-1.0 microg/L), and accordingly, %leptin significantly decreased from 133%+/-16% to 98%+/-11% (P < .05). A total of 6 months of observation in 12 hyperthyroid patients showed the same alterations in the anthropometric indexes, serum leptin, and %leptin. These results indicate that serum leptin is slightly increased in subjects with moderate hyperthyroidism, possibly due to the direct action of thyroid hormone, and the levels decline in accordance with the attainment of euthyroidism.
Nakamura
T
T
Department of Medicine, Jichi Medical School, Tochigi, Japan.
Nagasaka
S
S
Ishikawa
S
S
Hayashi
H
H
Saito
T
T
Kusaka
I
I
Higashiyama
M
M
Saito
T
T
D000273:Adipose Tissue / Q000033:anatomy & histology; D000293:Adolescent; D000328:Adult; D000368:Aged; D015992:Body Mass Index; D005260:Female; D006801:Humans; D006980:Hyperthyroidism / Q000097:blood*; D020738:Leptin / Q000032:analysis*; D008875:Middle Aged; D013972:Thyrotropin / Q000502:physiology
D020738:Leptin; D013972:Thyrotropin