Triploid Heteropneustes fossilis (Bloch) showed
sterility and higher growth potential than the normal diploid fish. Activities of some metabolic
enzymes such as cytosolic
NADP-malate dehydrogenase (
NADP-MDH), mitochondrial
NAD-malate dehydrogenase (
NAD-MDH) and
glutamate pyruvate transaminase (GPT) were evaluated in liver, brain and kidney along with
glucose-6-phosphate dehydrogenase (G-6-P D) in ovary of female
triploid catfish. Activities of these
enzymes showed distinct seasonal periodicity, mostly with highest activities in prespawning and spawning periods, in both diploid and
triploid catfish but differed in magnitude. In
triploid liver, GPT showed higher activity than the diploid counterpart in prespawning and spawning periods. On the contrary, mitochondrial
NAD-MDH and cytosolic
NADP-MDH in this organ showed a consistent lower activity than the diploid in all stages or in some stages of reproductive cycle respectively. Interestingly, none of the
enzymes in brain and kidney of
triploid female catfish showed significant changes in comparison to the diploid counterpart. The
triploid ovary maintained a significantly lower level of G-6-P D activity throughout the resting, preparatory and pre-spawning periods compared to the diploid ovary. Lower level of malic
enzymes (
NAD-MDH and
NADP-MDH) in liver and G-6-P D in ovary are in close synchrony with lower level of
estradiol-17beta in plasma of female
triploids as found in earlier study.