Leptin: the voice of the adipose tissue

Leptin is a newly discovered hormone that acts as a feedback signal from the adipose tissue. It plays a pivotal role in the modulation of neuronal and hormonal systems involved in the regulation of body weight and reproductive functions. This brief overview focuses on the regulation of circulating leptin levels and leptin in extreme clinical states of body weight, summarizing mainly results from the University of Giessen in collaboration with other groups. Finally, a possible role for leptin is presented.