[Evaluating genetics and environment in development of obesity]

Previous studies with twins had demonstrated that heredity exerts a definite impact on the development of overweight even more than environmental conditions of nutrition. In recent years studies of molecular genetics in imbred obese mice lead to the discovery of the ob-gene coding for the expression of the ob-protein (leptin) in adipose tissue. Mutation of this gene and also of other genes coding for the expression of receptor proteines for leptin were also discovered in obese mice. In humans, however, mutations of the ob-gene were found only in a few families with hereditary obesity obviously as rarities as compared to a huge number of overweight people with high leptin of normal structure in western societies. About the molecular structure of leptin receptors or its possible mutation in obesity are no human results are available at the present time. In this survey further observations about genetics and mutations of transmitters regulating feeding and for energy expenditure are reported. Although all these results come from animals it may be presumed that they will provide an experimental basis for a better understanding of genetic mechanisms leading to obesity in humans and also for future development of drugs interfering with these mechanisms thus offering a chance for medical treatment of obesity.