Insulin increases leptin mRNA expression in abdominal subcutaneous adiposetissue in humans

Insulin regulates expression and production of leptin in rodents but whethe r this is also true in humans remains unclear. To test the effects of acute hyperinsulinemia on expression of leptin mRNA in humans, percutaneous need le biopsies of abdominal subcutaneous adipose tissue were performed at base line and immediately following a 200-min two-step hyperinsulinemic-euglycem ic glucose clamp in 16 Pima Indians (8M/8F). Leptin mRNA was quantified by reverse transcription, PCR amplification and expressed relative to actin mR NA. Leptin mRNA levels were higher in women than men (25.6 +/- 1.7 v 16.9 /- 2.1 relative units, P = 0.003) at baseline. Baseline levels were directl y related to percentage body fat (r = 0.54, P = 0.03) and fasting plasma gl ucose concentrations (r = 0.57, P = 0.02) and were negatively correlated to glucose disposal at physiologic insulin concentrations (750 +/- 40 pmol/L) during the clamp (r = -0.51, P = 0.04). Acute hyperinsulinemia (final insu lin concentration 11560 +/- 950 pmol/L) increased leptin mRNA levels in 13 of 16 individuals an average of 13% (21.3 +/- 1.7 to 24.2 +/- 1.2 relative units, P = 0.01). Changes in leptin mRNA were directly related to glucose d isposal rates during physiologic hyperinsulinemia (r = 0.54, P < 0.04). The se results suggest that the expression of leptin mRNA is regulated by insul in in humans, as it is in rodents, (C) 2000 Academic Press.