Introduction to the reviews on peptides and the control of food intake and body weight.

The progress in the identification of peripheral and brain peptides that affect food intake and body weight is discussed in the accompanying 11 reviews. The reviews, succinct and critical, are useful guides to a dispersed literature that began in 1957. As reflected through the prism of these reviews, the field looks like a few small islands of scientific understanding surrounded by a vast sea of uncertain phenomena. This introduction discusses four themes that pervade the reviews. These are: (1) how to establish that an effect of a peptide is a physiological function of the endogenous peptide; (2) the importance of the interactions among peptides, amines and steroids for the central integration that underlies the control of food intake and body weight; (3) the need for simple and convenient generalizations to organize and interpret the apparently endless empirical reports; and (4) the persistent problems that remain untouched by current information, especially dietary-induced obesity and the role of peptides in the neural networks that control spontaneous eating. Copyright 1999 Harcourt Publishers Ltd.