The phenomenon of ketosis has intrigued physicians and biochemists ever since the ketone bodies, acetoacetic acid, β-hydroxybutyric acid, and acetone were identified almost 100 years ago in the urine of patients with diabetic acidosis.1The decade beginning in 1930 marked the opening of a period of intense interest in the role of the endocrines in ketosis, sparked by the almost simultaneous discovery and investigation of the ketogenic activity of certain pituitary extracts by Burn and Ling,2Anselmino and Hoffman,3-5Black, Collip, and Thomson,6and Rietti.7-10Especially noteworthy during this period was the work in the laboratories of Houssay,11-13Long,14-16Mirsky,17-20Somogyi,21,22and Stadie.23Progress in this field was impeded to some degree, however, by methodological difficulties, by lack of availability of purified hormones, and by large gaps in knowledge concerning the details of the metabolic processes involved in fat catabolism and anabolism and in ketogenesis itself. Thanks to the brilliant