A study of the effects of propranolol and/or K 1366 on the distribution of Rb86 clearance in the canine heart under selective coronary hypotension

Effects of beta-blockers o-[2-hydroxy-3-(tert.-butylamino)-propoxy]-benzonitrile (Kö 136 1366) and propranolol, on regional Rb86 clearance in the dog myocardium under selective coronary hypotension were investigated. Selective coronary hypotension of the left circumflex artery below 50 mmHg significantly decreased the Rb86 clearance and its I/O ratio of the involved myocardium. Kö 1366 and propranolol had a general trend to decrease the regional Rb86 clearance in the non-ischaemic region and to increase it in the ischaemic region when compared with that of the control group. Therefore, the gradient of regional Rb86 clearance between the non-ischaemic and ischaemic region may decrease. However, these changes were not statistically significant. Although both Kö 1366 and propranolol groups demonstrated similar haemodynamic changes, a reduction in heart rate was larger with propranolol infusion than with Kö 1366. On the contrary, a decreasing rate in systemic arterial blood pressure was marked with Kö 1366. Epicardial ECG ST elevation was reduced after propranolol infusion, not after saline or KO 1366 infusion.

Protein nutrition and aging

Twenty-four female rats consisting of 6 sets of litters were used for the experiment. After weaning, rats were divided into 4 groups and fed with 10, 18, 27 and 36% casein diet. Effect of protein nutrition on aging was examined from the anthropometric and biochemical viewpoint. The difference of growth in body weight, and that of the urinary excretion of creatinine and 17-ketosteroids observed in the early period of growing disappeared by the end of growth period. From 1 year after birth, serum alkaline phosphatase activity and serum cholesterol were also measured. However, effect of protein nutrition on these parameters was not clear due to the scatter of data. The difference in diet did not affect life span in the present experiments, but the effect of the variance of litters on it seemed to be significant between the rats fed 18% casein diet and those fed 10% casein diet. Rats fed high-protein diet had a great number of lesions in the kidney and hypophysis, and often an incidence of tumors.