Ribonucleic acid and protein metabolism in the gut. I. Observations in gastro-intestinal cells with rapid turnover

This paper reports the findings of an investigation of ribonucleic acid (R.N.A.) and protein metabolism in those epithelial cells of the gastrointestinal tract which have a rapid turnover, and correlates the results with the rate of production of new cells.

Role of pancreatic digestion in cholesterol absorption

The exclusion of pancreatic juice had no significant effect on elimination of endogenous cholesterol in the rat but increased it slightly in three dogs. Forty per cent of the dietary cholesterol was absorbed without and with pancreatic exclusion in the presence of a fat-free diet. Hence, pancreatic juice is not specifically necessary for the absorption of cholesterol. Pancreatic exclusion had no effect on the absorption of either dietary cholesterol or fatty acid, or both, when oleic and palmitic acid were fed. This indicates that any effect pancreatic exclusion may exert on cholesterol absorption when a fat containing diet is fed depends on the change in the utilization of the fat resulting from the exclusion. In the case of corn oil, triolein, trielaidin and tallow but not with tripalmitin, pancreatic exclusion was followed by an increased fecal elimination of both fatty acid and cholesterol. The increment of fatty acid elimination was large enough to dissolve the excess cholesterol excreted in the rats with pancreatic exclusion, except in the case of trielaidin. The only statistically significant decrease in the absorption of dietary cholesterol which resulted from pancreatic exclusion occurred when one of the unsaturated fatty acid esters, namely, corn oil, triolein, or trielaidin was the fat fed. These observations fail to show that pancreatic cholesterol esterase plays a specifically essential role in the absorption of free dietary cholesterol.