The dependence of the organism on its food supply is well recognized. Protein malnutrition, avitaminoses, effects of fats or carbohydrates, trace metal deficiencies, toxicity of some food additives are all related to the quality of the diet. During the past 20 years it has been recognized that the metabolic activity of the cells of the body is determined not only by the quality of food intake but by its periodicity. The tissues respond quite differently to the same diet depending on whether it is fed continuously throughout a 24 hr day or for only 1 or 2 hours per day, or every other day. In order to adapt successfully to the ingestion of large amounts of food at widely spaced intervals the animal must make a very complicated set of adjustments in 1) the gastrointestinal tract, 2) the secretory activity of glands which are concerned with the disposition of nutrients (for example, insulin) and 3) reorganization of the biochemical machinery of the cells so that they can accommodate periodic flooding with nutrients and store the excess for mobilization during periods of food deprivation. This lecture will deal with a brief historical review of our current ideas about periodicity of food intake; some of the gastrointestinal adaptation that occur on some “stuffing” regimens; the central role of insulin (and, possibly, insulin antagonists) as signals to the tissues; the functional and biochemical modifications that occur in tissues, particularly liver and adipose tissue, as a result of exaggeration of the usual fast-refeed cycle; some recent ideas about the role of cyclic AMP in enzyme adaptation, especially of lipogenic enzymes; and finally, the potential of “stuff and starve” eating habits to contribute to the pathogenesis of several diseases. The latter include 1) experimental gallstones, 2) experimental atherosclerosis in chickens and 3) lipemia, vascular disease and myocardial infraction in man.
1. Fifteen arginyl peptides have been isolated from the L fraction in bovine milk whey, using the techniqes of chromatography and high voltage paper electrophoresis. Among the fifteen peptides, the ten peptides were ninhydrin negative but were only Sakaguchi's reaction positive indicating to have no amino terminal. Four strongly basic peptides, L-1-4-1, L-2-2-1, L-2-4-1, and L-3-5-1, were detected by high voltage paper electrophoresis. 2. Main components of the peptides in the L fraction consist of aspartic and glutamic acids, glycine, alanine, valine and basic amino acids, lysine and/or histidine besides arginine. No sulfur containing amino acids were detected with one exception of cystine in L-2-10-1.