THE DISTRIBUTION OF RADIOACTIVE CARBON IN THE RAT AFTER THE ADMINISTRATION OF RANDOMLY LABELLED C¹⁴-β-CAROTENE

Abstract

The distribution of C14 has been studied in rats following the oral administration of C14-β-carotene, which is known to be readily converted to vitamin A in the intestine. The rats were maintained in a respiration chamber and individuals removed at various time intervals up to 28 hours after dosing, and the concentration of C14 in tissues was determined. The counts per million per gram of tissue was higher in the adrenal glands and hypophysis than in the other organs examined. The pattern of C14 distribution in intestine, liver, kidneys, and blood appears consistent with current knowledge of the metabolism of vitamin A.

Biosynthesis of retinol as affected by dietary protein and feeding patterns in carotene-fed rats

“…Plasma 14 contained 20% of the recovered C 17 minutes after injection but only 1-4% of the radioactivity after longer time intervals indicating that plasma does not serve as a reservoir for 14 deposition of vitamin A. Willmer and Laughland (1957) fed C-3-carotene to vitamin A-deficient rats and found after various time intervals that the total radioactivity recovered was greatest in the liver followed by the intestines, adrenal glands, blood, kidneys, lungs, heart, hypophysis, stomach and spleen. With the exception of blood and the retina, vitamin A in the body exists mainly in its esterified form (Moore, 1957) and predominately as palmitate .…”

Studies on the biosynthesis of retinol and the effect of protein in rats

“…Later it was found that this compound hampered the accurate determination of these samples by radioassay methods. Willmer and Laughland (1957) overcame this difficulty. Following saponification of the plant tissue, they extracted the unsaponifiable fraction and cooled it by passing it through dry ice to remove sterols.…”

“…Whereas diethyl ether was employed for extraction purposes in the study of Willmer and Laughland (1957), Lilly et al…”

“…Another procedure in which saline in varying quantities was forced through the lumen to flush out the intes tinal contents was used subsequently by these co-workers. Others have followed a similar procedure (Willmer and Laughland, 1957;Ganguly et al. 1959;Olson, 1961a;Deshmukh and Ganguly, 1964).…”

“…The extraction procedures were an extension of those described by Willmer and Laughland (1957). The extraction and purification were done in a room with no direct light source.…”