Protein bound folates in liver of castrated rats

The effect of castration and testosterone treatment on the distribution of [3H] radioactive and endogenous bound folates in hepatic cytosolic folate binding proteins (FBP-C) has been studied in rats. The distribution of [3H] radioactive bound folates in these FBP's shows no significant difference in the three experimental group animals. On the contrary a significant decrease in the amount of endogenous bound folates is observed in castrated if compared with control rats, particularly marked for FBP-CI and FBP-CII bound folates. The testosterone treatment of castrated rats partially restores bound folate levels. The decrease of bound folates in castrated rats might be ascribable to a lower availability of longer-chain forms, almost the ones that bind to FBP's; however lower binding protein content and/or lower affinity for ligands cannot be excluded.