The treatment of adrenaline to normal toads increased Na+-K+-ATPase activity significantly in both the liver and muscle homogenates. The study of enzyme kinetics, by taking various substrate concentrations, indicated an allosteric activation up to Vmax. However, after attainment of Vmax, subsequent increase in substrate concentration exhibited substrate inhibition depressing the enzyme activity.

The studies involving the effect of epinephrine on metabolic profiles in general and that of enzyme activities in particular are limited to mammals and certain species of fishes. The effect of the above hormone on metabolic parameter in amphibian species is very scanty. Amphibians, by combinations of many unique morphological structures, behavioral responses and physiological mechanisms have adapted to life in nearly all terrestrial habitats. Possibly, enough such physiological adaptations are mediated by adrenaline since the hormone is wellcharacterized as an emergency hormone for its adaptive role in stressful situations.

The present study reports the activity of Na⁺-K⁺-ATPase, an enzyme system largely responsible for creating a transmembrane potential gradient, which is involved in the maintenance of the membrane potential of excitable tissues, the vehicle for transmission of impulses in the form of an action potential

Life Sciences Journal, Milk Production Systems in Bure District, Amhara National Regional State, Milk Development, Marketing Systems, Agricultural Products, Feeding Systems, Calf Rearing, Milk Feeding, Bucket Feeding, Partial Suckling, Dietary Treatments, Veterinary Services.