Chronic inhibition of the sympathetic nervous system with guanethidine: Effects on body and organ weights and food intake of chicks given a phenylalanine excess diet

To investigate the effect of chronic inhibition of the sympathetic nervous system on food intake in the chicken, guanethidine (GTD, 0 or 50 mg/kg body weight/d), an adrenergic blocker, was subcutaneously administered to chicks for 4 weeks starting at 10 days of age in experiment 1. Chronic GTD decreased body weight gain and brain weight, but not heart, and adrenal gland, weights. In the second experiment., effects of chronic GTD and dietary excess phenylalanine (Phe) on daily food, intake were investigated, at one week interval for 4 weeks. At each week, food intake was determined at 1, 2, 4, 6, 12 and 24 h after feeding. Significant dietary effects of excess Phe were found at several times in every week, but chronic GTD administration did not alter intake of Phe excess diet. Main effect of GTD could, be detected until 2 weeks of feeding. A significant interaction between GTD and. Phe treatments was detected in some times determined, until 3 weeks of feeding, implied that effects of excess Phe improved by GTD. At. a. final week, dietary excess Phe decreased, food intake, but the effect of GTD disappeared. It is possible that the anorexia by excess Phe may be affected by sympathectomy in an early week of age.