ISOZYMIC STRUCTURE AND PYRUVATE INHIBITION OF LACTATE DEHYDROGENASE OF VENTRICLE PECTORALIS MUSCLE AND CEREBRUM AND TOTAL LDH ACTIVITY OF CEREBRUM DURING MORPHOGENESIS OF HOUSE SPARROW PASSER DOMESTICUS

1. 1. Study of the house sparrow reveals that there is a shift in predominant lactate dehydrogenase (LDH) isozymes for ventricle, but not for either breast muscle or cerebrum during development, a pattern of differentiation unlike that of chicken heart and breast muscle. 2. 2. Values of pyruvate concentration giving optimal LDH velocity for sparrow ventricle and pectoralis muscle are similar to published values for these two chicken tissues. The absolute pyruvate concentration giving optimal velocity of LDH isozymes in ventricle decreases during development. However, these concentrations of pyruvate fail to differ significantly among five age groups. The same relationship exists for developing cerebrum. There is a gradually increased inhibition of LDH activity produced by high pyruvate concentrations for ventricle, but not for cerebrum. These catalytic properties coincide with the isozymic changes observed in these tissues during morphogenesis. 3. 3. The observed pattern of inhibition results in a higher NADHL/NADHH ratio for adult ventricle than for adult cerebrum or pectoralis muscle. 4. 4. The total LDH activity of cerebrum reaches a minimum just after hatching and then it increases as development progresses. © 1969.