Vitamin D affects Krebs cycle NAD-linked oxidoreductases from chick intestinal mucosa.
Vitamin D3 administration affects the NAD-linked oxidoreductase activities of Krebs cycle from intestinal mucosa of vitamin D-deficient chicks. Vmax values were increased in all of them, while K0.5 for substrate remained unchanged except for 2-oxoglutarate dehydrogenase, which showed lower affinity for oxoglutarate. Addition of Ca2+ to the incubation medium increased the affinity of 2-oxoglutarate dehydrogenase and NAD-isocitrate dehydrogenase for their substrates either in the vitamin D3 treated group or in the control one. The activity of succinate dehydrogenase, a FMN-dependent oxidoreductase, was not modified by vitamin D3 administration. The oxygen consumption of the intestinal mitochondria was not altered by cholecalciferol treatment to vitamin D-deficient chicks. The reason why vitamin D3 selectively affects the NAD-linked oxidoreductase activities of the Krebs cycle remains unknown. The vitamin D hormone, 1,25(OH)2D3, appears to be the mediator of the response.
Pérez
A
A
Cátedra de Química Biológica, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Argentina.
Díaz de Barboza
G
G
Pereira
R
R
Tolosa de Talamoni
N
N
D000818:Animals; D002645:Chickens; D002952:Citric Acid Cycle; D007413:Intestinal Mucosa / Q000378:metabolism*; D008928:Mitochondria / Q000378:metabolism; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism*; D014807:Vitamin D / Q000494:pharmacology*; D014808:Vitamin D Deficiency / Q000378:metabolism*
D014807:Vitamin D; D009247:NADH, NADPH Oxidoreductases