Upregulation of serum retinol in experimental acute renal failure

Serum vitamin A homeostasis was studied in rats with nonfiltering kidneys prepared by ligation of renal arteries. Within 1‐2 h of acute renal failure, the serum retinol level increased by 11‐73% and was maintained for at least 4 h. More than 90% of the increase in serum retinol was associated with retinol in the retinol binding protein‐transthyretin (RBP‐TTR) complex. The activities of acyl‐CoA:retinol acyltransferase and retinyl‐palmitate hydrolase were not altered by short‐term acute renal failure. Oral administration of 3 H‐labeled retinol 3 h before surgery resulted in 350% more tritium in the serum retinol‐RBP‐TTR complex of rats with acute renal failure as compared to sham‐operated rats; this increase represented the fraction of retinol in RBP‐TTR contributed by hepatic retinol from newly absorbed 3 H‐labeled retinol. Total retinol in the retinol‐RBP‐TTR complex was increased by only 60%. We conclude that short‐term acute renal failure causes rapid upregulation of serum retinol‐RBP‐TTR; the extent of the increase depends on the magnitude of hepatic vitamin A stores, particularly the retinol pools. We hypothesize that kidney modulates the regulation of hepatic release of retinol‐RBP from the pool of newly acquired retinol.— G erlach , T. H.; Z ile , M. H. Upregulation of serum retinol in experimental acute renal failure. FASEB J. 4: 2511‐2517; 1990.