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 regula ted in certain conditions such as obesity. In chronic renal failure, l eptin appears to be increased. However, little is known about leptin r egulation during chronic renal failure (CRF). Methods. We measured ser um leptin in eight well nourished: chronic hemodialysis patients (seve n males, one female) receiving anabolic factors for three days as eith er recombinant insulin-like growth factor-1 (rhIGF-1) or a combination of recombinant growth hormone (rhGH) plus recombinant IGF-1, in a ran dom cross-over trial. Results. Serum leptin values were in the range o f normal volunteers matched for body mass index. As reported in other conditions, serum leptin was strongly correlated with patients dry bod y wt (P = 0.01) and body fat (P = 0.0001). Both treatments affected se rum leptin in a rapid and opposite manner. RhIGF-1 decreased serum lep tin from 11.2 +/- 20.8 (SD) to 4.3 +/- 3.8 mu g/liter (P = 0.011), whe reas 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 variati ons after treatment. Conclusions. This study shows for the first time that both rhIGF-1 and rhGH acutely regulate serum leptin in dialysis p atients. Whether leptin changes are explained by the concomitant insul in variation should be further studied under renal failure conditions.