No effect of maternal niacin deficiency on niacin metabolism in newborn brain.
The effects of maternal niacin and tryptophan deficiency on: (1) total niacin levels and (2) niacinamide entry into brain, blood, and liver of newborn rabbits were studied. The deficient maternal diet produced a decreased concentration of the oxidized niacinamide-containing vitamers in the liver (73% of controls; P less than 0.05) but not in the brain of newborn rabbits. In both deficient and control newborn rabbits, the entry of [14C]niacinamide into brain and liver was saturable with an increasing [14C]niacinamide concentration in plasma. Also, the formation of [14C]NAD in brain and liver and [14C]niacinamide mononucleotide in blood was saturable. In vitro, the affinity of the saturable accumulation system for [14C]niacinamide in both newborn and adult rabbit brain slices was comparable (0.9 microM). The avid saturable, uptake system for niacinamide in rabbit brain contributes to total niacin homeostasis in brain.
D000818:Animals; D000831:Animals, Newborn; D001921:Brain / Q000378:metabolism*; D002531:Cerebellum / Q000378:metabolism; D005260:Female; D066298:In Vitro Techniques; D007700:Kinetics; D008431:Maternal-Fetal Exchange; D009536:Niacinamide / Q000378:metabolism; D009539:Nicotinic Acids / Q000172:deficiency / Q000378:metabolism*; D009928:Organ Specificity; D011247:Pregnancy; D011817:Rabbits
D009539:Nicotinic Acids; D009536:Niacinamide