Acute leptin regulation in end-stage renal failure: The role of growth hormone and IGF-1

Background. Leptin, a recently discovered peptide involved in nutrient intake and energy expenditure, has been shown to be abnormally regulated in certain conditions such as obesity. In chronic renal failure, leptin appears to be increased. However, little is known about leptin regulation during chronic renal failure (CRF). Methods. We measured serum leptin in eight well nourished: chronic hemodialysis patients (seven males, one female) receiving anabolic factors for three days as either recombinant insulin-like growth factor-1 (rhIGF-1) or a combination of recombinant growth hormone (rhGH) plus recombinant IGF-1, in a random cross-over trial. Results. Serum leptin values were in the range of normal volunteers matched for body mass index. As reported in other conditions, serum leptin was strongly correlated with patients dry body wt (P = 0.01) and body fat (P = 0.0001). Both treatments affected serum leptin in a rapid and opposite manner. RhIGF-1 decreased serum leptin from 11.2 +/- 20.8 (SD) to 4.3 +/- 3.8 mu g/liter (P = 0.011), whereas the combination of rhGH + rhIGF-1 increased serum leptin from 7.4 +/- 9.4 to 21.0 +/- 32.9 mu g/liter (P = 0.011). Regression analyses indicated a linear regression between serum leptin and insulin variations after treatment. Conclusions. This study shows for the first time that both rhIGF-1 and rhGH acutely regulate serum leptin in dialysis patients. Whether leptin changes are explained by the concomitant insulin variation should be further studied under renal failure conditions.