Comparative effects of nicotinic acid and nicotinamide on cholera toxin-induced secretion in rabbit ileum

Abstract

Nicotinic acid reduces the cholera-toxin induced fluid secretion in experimental animals but its toxicity at high doses prevent its therapeutic use in patients suffering from cholera. This study aimed to determine whether nicotinamide, the non toxic amide derivative of nicotmic add, is as effective as nicotinic acid in inhibiting cholera toxin induced intestinal secretion in vivo. Four intestinal loops, with their blood supply intact, were isolated in 30 rabbits and injected with cither (i) 30 mM mannitol, (ii) 30 mM mannitol + 10 ug cholera toxin, (in) 30 mM glucose, or (iv) 30 mM glucose + 10 ug cholera toxin. These rabbits were then randomly assigned to three groups receiving intraJuminally cither 100 mg/kg of nicotinic acid, 100 mg/kg of nicotinamide, or 10 ml/kg of Ringer solution. Measurement of intestinal fluid accumulation showed that nicotinic acid, but not nicotinamide, significantly reduced cholera toxin induced intestinal secretion