Short-term stressor effects of propranolol

1. The effects of propranolol (10 mg/kg) on plasma cholesterol, glucose, corticosterone and free fatty acids, on adrenal mass and cholesterol content and on body temperature were determined over a 24-h period in 3-week-old Light Sussex chicks. 2. Changes in plasma cholesterol were equivocal, though there was perhaps a trend towards hypercholesteraemia. 3. Birds became hypoglycaemic within an hour but were hyperglycaemic between 2 and 4 h. At 24 h they were normoglycaemic. 4. Plasma corticosterone was increased markedly at 1 h but was decreased compared with the control at 2 h ( P < 0.01). Thereafter the concentration was in the normal range. 5. There was an enhanced hyperlipacidaemia in the treated birds after 1 h. 6. Adrenal cholesterol stores were decreased by 10% at 4 h but were unaffected at all other times. 7. Colonic temperature decreased by 1x6 degrees C after 2 h but was normal by 4 h. 8. It is concluded that propranolol has mild stressor activity which is lost within 24 h.