[Comparative studies on perfused adult and fetal guinea pig liver metabolism before and after anoxia loadings, with special reference to intracellular redox state].

In order to pursue peculiarities of fetal metabolism, fluorometric measurements of intracellular nicotinamide adenine dinucleotide (NAD) were made in perfused adult and fetal guinea pig livers following the administration of various agents before and after anoxia loadings. Oxygen and glucose concentrations of the drainage from perfused livers were also measured. The following results were obtained: (1) NAD reduction, oxygen uptake and glucose production were observed to be lower in fetal livers in response to lactate, pyruvate, octanoate and ethanol than the adult ones, suggesting immaturity of fetal intracellular metabolism. (2) However, on the basis of NAD reduction following norepinephrine (NE) administration, fetal plasma membraneous receptors were considered to be similarly active, although induced glucose production was lower than the adult ones. Sequential NE administrations yielded consecutive changes in NAD reduction and glucose production, suggesting active response of fetal plasma membrane to NE. (3) After one hour and three hours of anoxia loadings, adult NAD reduction rates by NE were decreased remarkably to 37% and 11%, respectively, of the control values on average, while fetal rates were reduced to only 61% and 45% of the control values, suggesting anoxic tolerance of fetal plasma membrane. (4) After three hours of anoxia loading, NAD reduction was observed following succinate administration in adult livers, indicating membraneous damage due to anoxia. No such changes were observed in fetal livers. (5) Scanning spectrophotometric studies demonstrated activities of mitochondrial cytochromes in perfused adult and fetal livers, indicating the efficacy of non-destructive in vivo measurements.