Dynamics of ascorbic acid stimulation of 26- 14 C cholesterol oxidation in guinea-pigs
Ginter, E.; Nemec, R.
Physiologia Bohemoslovaca 21(5): 539-545
1972
ISSN/ISBN: 0369-9463 PMID: 4266223 Document Number: 44707
Growing male guineapigs were deprived of ascorbic acid for 18 days or given 10 mg daily before an intraperitoneal injection of cholesterol-26-14C in a dose of 1.2 mu Ci/100 g bodyweight. Two days later, when the deprived group had lost about 12% of their initial weight, some of them were given an injection of 100 mg ascorbic acid and the rest saline. Expired CO2 was collected at increasing intervals for 48 h after the ascorbic acid injection and the animals were then killed. A second experiment was similar but the cholesterol was given on the 16th day of depletion and ascorbic acid 5 days later. The third experiment was on 35 guineapigs deprived of ascorbic acid for 20 days and killed without or from 6 to 48 h after an injection of ascorbic acid for study of its distribution in the tissues.In the first study injection of ascorbic acid into depleted guineapigs did not affect oxidation of cholesterol in the first 24 h but in the second 24 h there was a significant stimulation and the regression showing the percentage of the labelled cholesterol oxidised with time was significantly higher than in depleted animals given saline. Treated guineapigs had more ascorbic acid in liver and spleen when killed but amounts of cholesterol in the liver did not differ. The second experiment was similar except that the oxidation of cholesterol in the first 24 h was the same in both groups but in the second 24 h after injection of ascorbic acid the regression coefficient rose significantly. It was calculated that guineapigs given ascorbic acid catabolised 18.35 plus or minus 3.19 mg cholesterol in 24 h while deprived controls catabolised 7.37 plus or minus 0.54 mg. The single injection of ascorbic acid caused a highly significant increase of amounts in all tissues examined, greatest at the earliest sampling 6 h after injection but still substantial after 48 h. The mechanism by which ascorbic acid may stimulate cholesterol breakdown is discussed.