Yoshihiro Shidoji

Competitive protein-binding radioassay for retinoic acid

Rat testes cytosol treated by Blue Sepharose was employed in a simple and sensitive method for the determination of retinoic acid in the rat serum, liver, and intestine. The method permits the detection of as little as 3 ng of retinoic acid. The mean concentrations of retinoic acid in normal male rats were 33.5 ng/ml of serum, 624.9 ng/g wet wt of liver, and 444.3 ng/g of intestine.

Comparative studies on binding proteins specific for retinol in serum and cytosol of young yellowtail Seriola quinqeradiata

Abstract 1. 1. Two cytosol binding components specific for retinol (retinol carrier protein; RCP) and for retinoic acid (retinoic acid carrier protein; RACP) were demonstrated in the eye of young yellowtails. 2. 2. The RCP was very similar in properties to piscine serum retinol-binding protein (RBP), but the 2 proteins different slightly as to isoelectric point. 3. 3. In contrast to the mammalian and avian RCP, the piscine RCP retained a lower, but definite binding affinity for retinoic acid. Hence, it is designated RCP (fish type or F). 4. 4. On the other hand, the RACP showed binding affinity only for retinoic acid.