Why? Endocrinology is the study of the mechanisms that regulate essential body functions such as reproduction, metabolism, water balance, feeding, and growth. Research in these fields is fascinating and has widened our view of human physiology. New drugs for the control of feeding and food uptake or sexual activity have reached the medical practice but have also resulted in a gray market for substances of doubtful efficiency. E-mail folders choke on pseudomedical spam. Neuropeptide Y, a nerve cell product which is involved in the generation of hunger, has been the focus of some 2,000 articles since the beginning of the millennium.