RESPIRATION AND NICOTINAMIDE ADENINE DINUCLEOTIDE PHOSPHATE DEPENDENT ENZYMES IN LETHAL AMPHIBIAN HYBRIDS RANA NIGROMACULATA BREVIPODA _??_× RANA RUGOSA _??_

Abstract

The rate of respiration of lethal hybrid embryos begins to diminish at the late blastula rather than before the retardation of gastrulation is appreciable. Evidence that the activity of NADP dependent enzymes was also lower in the arrested-gastrula suggests an inhibition of the pentose cycle.