Effect of inhibitors on sugar and amino acid transport in two teleosts.

After the addition of ouabain or potassium cyanide (10(-4)M) to the filling solution, inhibition of the transport of sugars and amino acids was noted in the intestine of both the fish, Ophiocephalus punctatus (carnivorous) and Heteropneustes fossilis (omnivorous). Regional as well as nutrient variations occurred in the transport process. There was a positive but slower transport of nutrients in the beginning but later a negative transport of sugars and amino acids was noted in different portions of the intestine. The negative transport of amino acids was comparatively higher than that of sugars though the inhibition pattern by these two substances was almost similar. Potassium cyanide was a stronger inhibitor of the transport process than ouabain. The rate of nutrient transport was comparatively higher in Heteropneustes than in Ophiocephalus.