The metabolism of 35S-labelled 2-thiolhistidine and ergothioneine in the rat

Abstract

[s35]2-thiolhistidine and [S35] ergothioneine were administered separately in the diet to rats for 21 days and their distr. in the animals was detd. The rate and pattern of urinary excretion was studied in both cases; 5% of the thiolhistidine and 35% of the ergothioneine S was excreted as sulphate. The S of thiolhistidine and ergothioneine was not incorporated into other S compounds of the rat. There was no increase in the ergothioneine blood level after thiolhistidine admn., nor was there any accumulation of thiolhistidine in any tissue of the rat. It was concluded that thiolhistidine cannot be methylated by the rat to yield ergothioneine. Dietary ergothioneine was incorporated into the blood cells, bone marrow, liver and kidney. The presence of non-radioactive ergothioneine in the liver of rats after the admn. of [S35]-thiolhistidine was observed. The absence of ergothioneine from the seminal-vesicular secretion of the rat (as opposed to the pig) is a true sp. difference and is not due to any deficiency of ergothioneine.