ASPECT OF THE METABOLISM OF CYANIDE IN THE RAT

No Thumbnail Available
Date
1978-09
Authors
OKOH, PATRICK NWANZB
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
The use of inorganic cyanide for cyanide metabolism studies in animals has the advantage that the cyanide administered is fully available as opposed to cyanogenic glycosides in which the cyanide radical is not completely liberated in the animal body. However, when KCN was added to the diet which had been moistened with water, it was lost by transformation to other products, and perhaps also as volatile HCN. A preliminary study revealed that formate is one of the products formed. A method was developed for the addition of KCN to the normal rat diet, in which no significant loss or transformation of the added substance occurred.By this method it was possible to compare tho relative toxicities of KCN and vitamins A and D when mixed in the diet, as measured by weight gain in growing rats. KCN given to groups of rats at a dose level of 77 umoles/rat/day in the diet did not diminish weight gain whereas vitamins A (38•5 umoles/rat/day) or D, (0.55 umoles/rat/day) significantly diminished weight gain in rowing rats. A study of tho metabolism of " C-labelled cyanide was carried out in the rat exposed to semi-continuous intake of KCN in the diet for throe weeks. The pattern of excretion and tissue levels of" C activity was similar after subcutaneous or intraperitoneal injections and oral administration of Na1kCN. After intraperitoneal and subcutaneous injections of Na"CN, 2k of dosed activity was excreted in the urine within 9h of which 71% was in the form of thiocyanate. The corresponding value after 9h in the faeces was 0.5. • About 4.3 of the injected activity appeared in the respiratory air of which 85 was present as CO and only 15 as cyanide. All tissues contained radioactivity 9h after the Na"CN administration but very high amounts were found in the gastrointestinal tract, particularly in the stomach, which accounted for 18% of the total dosed activity. Moat of this was in the contents of the stomach, of which over 80% was in the form of thiocyanate. When a small amount of KS11CN was given by mouth to the rat with elevated plasma ScN level, most of the activity waa excreted in the urine (mainly as SCN) and only small amounts were found in the faeces. This indicated that the thiooyanate secreted into the stomach contents of the rat was largely reabsorbed by the intestine into the body fluid, to be partly excreted in the urine and partly resecreted into the gastric juice. The time of initial secretion of thiocyanate into the rat stomach contents after subcutaneous injection of cyanide was calculated to bo 7 min, while the rate of secretion was estimated to be 0.31 of the administered dose per minute
Description
A Thesis Submitted in accordance with the requirements of the UNIVERSITY OF LIVERPOOL for the degree of DOCTOR IN PHILOSOPHY September, 1978
Keywords
ASPECT,, METABOLISM,, CYANIDE,, RAT,
Citation
Collections