Comparative effects of osmotic and secretory diarrhoea on brush- border disaccharide hydrolases in rat

Abstract

The effects of diarrhoea on the activities of brush-border disaccharidases namely lactase (EC 3.2.1.23), maltase (EC 3.2.1.20) and sucrase (EC 3.2.1.48 ) of Sprague-Dawley strain albino rats were induced in the rats with mannitol whil e secretory diarrhoea w a s induced with Salmonella typhimurium after an initial treatment with streptomycin. The activities o f the enzymes were significantly reduced by diarrhoea. T he extent of reduction in enzyme activity varied in the different segment o f the small intestine in all the groups. T he jejuno-ileal region had more change s in enzym e activities than in the duodenum. Higher activity levels wer e observed for maltase than for lactase. In the osmotic diarrhoea model, lactase activity w a s significantly lowered (P< 0.05 ) in the experimental group from day 5 to 10. Maltase activity on the other hand w a s significantly lowered (P< 0.001) at the peak o f diarrhoea. Sucrase activity w a s als o lowere d significantl y ( P < 0.025 ) in the experimental animals within the first 10 days o f diarrhocal induction. In the secretory diarrhoea model, lactase activity w a s similar in all the experimental groups except for the streptomycin-salmonclla-trcatcd groups and control (P< 0.05). Higher lactase activity levels were observed in the secretory diarrhoea model compared to level in the osmotic diarrhoea model. Maltase activity levels were also lowered significantly ( P < 0.05 ) in the experimental animals. Streptomycin had no effect on the activity o f maltase.