Effects of Glucocorticoid on Components of Blood Serum and Amino Acids Composition of the Serum

For induction of fat deposit in meat, hypothyroidism is the most important factor. This study was carried out to confirm the effect of glucocorticoid on thyroidal function, using rats. Triamcinolone acetonid, a synthetic compound was used as glucocorticoid. Rats of an experimental group were injected singly subcutaneously with 0.9 mg of the compound and another group of rats served as control. The animals were sacrificed by decapitating at 2 hours and 4 hours following the injection. At the time of decapitating, blood was obtained from the animal respectively. A half portion of the blood serum was used for determination of such blood components as total protein (TP), albumin (Alb), globulin (Gl), blood ureal nitrogen (BUN), glucose(Glu), cholesterol (Chol), calcium (Ca), magnesium (Mg) and phosphorus (P). Another half portion of the serum was subjected to amino acid analysis, using a automatic amino acid analyzer. By injection of the glucocorticoid, concentrations of TP, Alb, and Gl decreased, and concentration of amino acids increased. This is due to gluconeogenesis induced by glucocorticoid. Serum phosphorus was elevated, and ratio of Ca/P decreased and P/Mg increased. These are indicative of lowered thyroidal function. Accordingly, glucocorticoid seemed to have a favourable effect on fattening cattle. Results of amino acid assay were summarized in Table 2. Most of amino acids increased by the injection of the compound, except glutamic acid and taurine. This is due to protein catabolism and gluconeogenesis. Concentration of serum glucose consistently increased. Increase of glycine concentration in serum is indicative of hyperthyroidism. This is, however, due to neoglucogenesis by cortisol. Low concentration of Mg is indicative of hyperthyroidism. Further study for the effect of glucocorticoid would be required, since glucocorticoid is considered to accelerate production of lean meat.