THE ABSORPTION OF FAT AND OF CHOLESTEROL IN THE RAT, GUINEA-PIG AND RABBIT

¹ Department of Biochemistry, University College, Dundee. (University of St. Andrews.)

1. The apparent absorption by rats of cooking fat, butter fat orolive oil at concentrations of 16·6 per cent. in synthetic (chemically defined) diets has been found to be 96, 97 and 97 per cent. respectively.

2. Cholesterol at a concentration of 1·7 per cent. is absorbed by rats from these diets at an average value of 0·3 g./ kg. body wt./day and an average absorption of 30 per cent. Apparent absorption occurs on a low fat diet.

3. On a basal diet of animal food cake and 16·6 per cent. olive oil rats absorb 92 per cent. of the oil, guinea-pigs 77 per cent. and rabbits 94 per cent.

4. On the rat-cake olive-oil diet containing 1·6 per cent. of cholesterol the absorption of cholesterol measured as unsaponifiable matter was, as g./kg. body wt./day, for rats 0·35, guinea-pigs 0·25, rabbits ·25. The average absorptions were for rats 34 per cent., guinea-pigs 47 per cent. and rabbits 77 per cent. (Table VI).

5. The levels for plasma cholesterol after feeding cholesterol are, in ascending order, rat, guinea-pig and rabbit (Table VII). Very high levels may be obtained with the rabbit.

6. Chemical analyses for the lipid constituents of the livers of the different animals after feeding cholesterol are given (Table VIII).

7. Rats and rabbits absorb olive oil more readily than do guinea-pigs. Cholesterol is apparently absorbed most readily by rabbits.

Note:

We are indebted to the Medical Research Council for a personal grant to R. O. T. and a grant for expenses.