Serum leptin levels in acromegaly--a significant role for adipose tissue and fasting insulin/glucose ratio.

BACKGROUND

Leptin plays an important role in controlling satiety and maintaining energy balance. Acromegaly is characterized by decreased fat, which increases after the disease is cured. Our objective was to investigate serum leptin in acromegaly in terms of disease activity, body fat content, insulin and glucose levels, and selected anthropometric variables.

MATERIAL/METHODS: We examined 40 patients with acromegaly and 20 sex- and age-matched controls for the levels of serum GH, IGF-I, leptin, glucose, and insulin, and for body composition by DEXA, BMI and WHR. In 10 cases the acute effect on serum leptin of a somatostatin analogue, lanreotide, was studied.

RESULTS

We observed lower leptin in patients with active acromegaly than in cured patients and controls. Body fat was higher in cured than active patients. In the patients, we found significant correlations (p<0.05) between leptin and percent body fat (r=0.77), leptin and body fat mass (r=0.74), leptin and fasting insulin (r=0.62), leptin and fasting insulin/glucose ratio (r=0.97), leptin and BMI (r=0.44), leptin and height (r=-0.47). In the controls there was a significant correlation (p<0.05) only between leptin and WHR (r=-0.45). A paradoxical decrease of the leptin level after lanreotide was observed in 7 out of 10 patients with active acromegaly.

CONCLUSIONS

Changes in leptin release in acromegaly are related to differences in body fat content and mass, and in insulin resistance. Leptin in acromegaly is not influenced directly by GH or IGF-I secretion. The acute effect of medical treatment of acromegaly by a somatostatin analogue on leptin levels differs from the effect of a radical cure following pituitary adenoma surgery.