The effect of vitamin E deficiency on the vitamin A reserves of the rat

IN early work in this laboratory on vitamin E deficiency in the rat a basal diet was used in which vitamin A was supplied as cod liver oil (ca.1000 IU. per g.).The oil was given at the rate of about 70 mg.per rat weekly.Since from the condition of some of the animals it was suspected that this level was not adequate, livers were taken at autopsy and the vitamin A in them was assayed by the SbC013 method.The vitamin A reserves were found to be absent or low.It is questionable whether at this comparatively low level of intake of vitamin A any other result was to be expected, but in subsequent experiments the vitamin A allowance was increased to 17 mg.weekly of halibut liver oil (ca.60,009 I.U.per g.).Determinations of liver reserves were continued.The results of these determinations, which have been reported in preliminary papers [Moore et al. 1939; Moore, 1939], are now given in detail.They indicate that in deficiency of vitamin E the vitamin A reserves of the liver may be much redijced.Opportunities arose in other experiments to compare the vitamin A reserves of rats having diets low in protein, with or without simultaneous deficiency of vitaminE.In contrast with the marked and consistent reduction ofthe vitaminA reserves in vitamin E deficiency the differences ascribable to protein deficiency were irregular and slight, and never passed beyond the range of difference in body weight found in the groups rpcceiving normal and low protein diets. The efficiency of the conversion of carotene into vitamin A in avitaminosis-Ewas also investigated and a slight reduction in the amount of vitamin A formed was found under the experimental conditions adopted. EXPERMENTALRats were killed by coal gas after being kept for varying periods on a diet deficient in vitamin E (light white casein 25%, cane sugar 50 %, lard 10%, salt mixture 5 %, dried yeast 10%).The animals used as positive controls received orally either a concentrate of vitamin E from wheat germ oil supplied by Glaxo Laboratories, Ltd., or a solution in arachis oil of dl-(-tocopherol or its acetate kindly presented by Roche Products, Ltd.At autopsy the livers were digested with alkali, the oils extracted with ether and alcohol, and their vitamin A was determined by the SbCl0 method [Davies, 1933].To convert~blue units into i.u. the approximate factor of 0'6 has been used [Moore, 1937].Vitamin A allowance.Except where otherwise stated vitamin A was given orally by pipette as one drop (17 mg.) of halibut liver oil per rat per week.The oil was kindly supplied by Allen and Hanburys, Ltd., and contained 60,000 i.u. of vitamin A per g.The vitamin A intake as halibut liver oil was therefore about 1000 i.U.perweek.In addition the rats givenwheat germ oil concentrateprobably received small amounts of carotene from this source.No attempt was made to ( 1321 ) 84-2