Ascorbic acid deficiency reduces hepatic apolipoprotein A-I mRNA in scurvy-prone ODS rats.

Using the ODS rat (genotype od/od) as a model, we investigated the effect of ascorbic acid deficiency on the expression of the apolipoprotein A-I gene. Male ODS rats (7 wk old, body weight approximately 140 g) were fed a basal diet containing ascorbic acid (300 mg/kg) or a diet without ascorbic acid for 14 d. Ascorbic acid deficiency lowered the serum apolipoprotein A-I concentration. The apolipoprotein A-I mRNA level in the liver of ascorbic acid-deficient rats was lowered to about 40% (P < 0.05) of that of control rats fed sufficient ascorbic acid. The mRNA level in jejunum was not affected by ascorbic acid deficiency. Ascorbic acid deficiency did not change the transcriptional rate of the hepatic apolipoprotein A-I gene, suggesting that post-transcriptional regulation was involved in lowering the mRNA level. The low level of hepatic apolipoprotein A-I mRNA was restored to the control level within 3 d after the administration of sufficient ascorbic acid. These data indicate that ascorbic acid deficiency lowers serum apolipoprotein A-I concentration through lowering its mRNA level and subsequent depression of its synthesis in liver.