THE TOTAL ANABOLIC ACTIVITY OF THE BLOOD AS A CONNECTING LINK BETWEENTHE INTESTINAL-FLORA THEORY AND THE INTERMEDIARY ACTION OF GROWTH PROMOTORS

Endocrine movements in rats induced by feeding of growth promoters, as well as in germ-free animals, were established in three experimental series. The following results were obtained: 1. In a preceding experim ent it was demonstrated that growth promoters, which were hither to pr esumed to influence only the intestinal flora (Toyocerin, fumaric acid , formic acid), have a direct anabolic effect on the liver. The effect ive concentrations are about 10-fold higher than those of other growth -promoting compounds; 2. After feeding of all the tested growth promot ers (Carbadox, Aureomycin, Flavomycin, CuSO4, Toyocerin, fumaric acid, formic acid) both to experimental and control animals, a statisticall y valid increase of anabolic regulators in the blood could be detected in parallel to a significant higher daily weight gain. The same resul ts were obtained after parenteral treatment with bovine somatotropin. Somatomedin C (insulin-like growth factor 1) levels, analysed in paral lel, were significantly increased in germ-free animals only; 3. Levels of catabolic regulators (corticosterone, thyroid hormones (T3/T4)) af ter feeding of growth promoters showed no statistically valid differen ces (time of feeding 28 days). A tendency in endocrine movements compa rable with those occurring at normal stress adaptation have been demon strated, e.g., with CuSO4: in the growth phase, decreasing corticoster one levels occurred simultaneously with increasing levels of T3 and T4 . This phase was followed by an increase in corticosteroids, normaliza tion of T3/T4 levels, and a decrease in daily weight gain; 4. It is di scussed whether growth promotion-independent of the method of inductio n-is always connected with an increase of anabolic endocrine regulator s. Growth promoters are reactive, but non-toxic, compounds which reach the cell and the cell nucleus-unlike somatotropin and somatomedins-wi thout receptors. Here, they cause a decrease in the concentrations of radicals and an increase in the redox potential resulting in the start of anabolic reaction sequences and-to ensure anabolism-in induction o f cell-specific anabolic peptides.