Comparison of dietary casein and soybean protein effects on plasma lipid and gastrin levels, hepatic delta 6-desaturase activity and coronary arteriosclerosis in male Sprague-Dawley rats. A 9-month study.

An increased concentration of gastrin was observed in plasma of male Sprague-Dawley strain rats fed on soybean protein diet for a 9-month period, compared with rats fed on casein diet. Both diets contained 0.5% (w/w) cholesterol. Protein-dependent differences were also observed in the fatty acid pattern of hepatic phospholipids, hepatic delta 6-desaturase activity, and plasma cholesterol. No signs of arteriosclerosis were observed in the aortas. Sixty percent of the hearts showed various degrees of lipid staining in coronary arterial branches of different sizes. Despite a large difference in plasma cholesterol level, there was no quantitative or qualitative difference between groups in the occurrence of coronary lipid staining.