The metabolism of cyanide and the gastrointestinal circulation of the resulting thiocyanate under conditions of chronic cyanide intake in the rat.

A study of the distribution of 14C-labelled cyanide was carried out in rats exposed to a regular intake of cyanide in the diet for 3 weeks. All tissues contained radioactivity 9 h after injection of 14CN- but very high amounts were found in the stomach, which accounted for 18% of the total injected radioactivity. Most of this was in the contents of the stomach, of which over 80% was in the form of thiocyanate. When a small amount of S14CN- was given by mouth to rats with elevated plasma thiocyanate levels, most of the activity was excreted in the urine and only small amounts were found in the faeces. This indicated the existence of a gastrointestinal circulation of thiocyanate, in which a substantial amount of this substance secreted into the stomach contents of the rat was reabsorbed by the intestine into the body fluid to be partly excreted in the urine and partly resecreted into the gastric contents. The likely implications of this are discussed.