[Genetic and molecular aspects of obesity: recent data]

Obesity is a disease responsible for many serious complications. The sharp rise in the prevalence of obesity in many countries is supplying a powerful drive to basic and clinical research. Several genes responsible for monogenic murine obesity have recently been identified. One of these genes encodes the OB protein, or leptine, which is secreted by fat tissue and inhibits appetite by means of an effect on the hypothalamus. In humans, obese subjects carrying a mutation of this gene or of the leptine receptor have been identified. Several other genes implicated in human obesity have been mapped to chromosomes 1, 11, 18, and 20. Several transcription factors that control fat cell differentiation have been identified, such as C/ERB alpha, beta, and delta; ADD1/SREBP1, and PPAR gamma 2. It has been established that fat tissue can secrete many factors, including TNF alpha, CETP, IGF beta, TGF beta, PGE2, and LPA. Mitochondrial uncoupling proteins (UCPs) are recently characterized proteins capable of uncoupling respiration and contributing to energy expenditures. The hypothalamic neuropeptides and their receptors are a focus of active research. About ten of these neuropeptides have been identified.