Leptin is a hormone produced and secreted from the adipose tissue. Its
physiological actions include the regulation of satiety, food intake
and energy balance, The production of leptin is increased by high insu
lin levels. Here, we demonstrate that leptin acts as an inhibitor of g
lucose-induced (20 mM) insulin secretion from isolated human islets. N
o effect was observed in the presence of lower glucose levels (2.8 and
10 mM glucose). The pancreatic beta-cell might represent a target of
a direct physiological action of leptin, We suggest the presence of an
''adipo-insular axis'' in which leptin mediates negative feedback fro
m the adipose tissue to the endocrine pancreas.