Effect of vitamin D deficiency and 1,25-dihydroxyvitamin D3 on metabolism and D-glucose transport in rat cerebral cortex.
We previously demonstrated that feeding rats Steenbock and Black's rickets-inducing diet produces remarkable changes in the metabolic pattern of the intestinal mucosa, kidney, and liver and in some membrane transport systems of intestinal mucosa and kidney. 1,25-Dihydroxyvitamin D3 administration to rachitic rats did not always prove to be effective in restoring normal values. We have now investigated the effect of 1,25-dihydroxyvitamin D3 on the levels of some metabolites in rat cerebral cortex, on the activity of some enzymes, and on the transport of 2-deoxy-D-glucose and D-glucose in synaptosomes. Our experiments were carried out on three rat groups: control, rachitic, and rachitic treated with 1,25-dihydroxyvitamin D3. The decrease in phosphorus content and the increase in citrate concentration observed in rachitic rat cerebral cortex were corrected by 1,25-dihydroxyvitamin D3 treatment. The activity of acetylcholinesterase, glucose-6-phosphate dehydrogenase, and acyl phosphatase significantly increased in rachitic rat synaptosomes, as well as NAD(+)-dependent isocitrate dehydrogenase in cerebral cortex mitochondria; the administration of 1,25-dihydroxyvitamin D3 to rachitic rats restored enzyme levels to normal. The transport of 2-deoxy-D-glucose and D-glucose in rachitic rat synaptosomes was lower than in the control group and returned to control values in consequence of 1,25-dihydroxyvitamin D3 treatment. The results reported here support the hypothesis of a participation of 1,25-dihydroxyvitamin D3 in some aspects of cerebral cortex metabolism.
Department of Biochemical Sciences, University of Florence, Italy.
M
M
Stio
B
B
Lunghi
T
T
Iantomasi
M T
MT
Vincenzini
C
C
Treves
D000110:Acetylcholinesterase / Q000032:analysis; D000818:Animals; D001692:Biological Transport; D002117:Calcitriol / Q000494:pharmacology*; D002118:Calcium / Q000097:blood / Q000378:metabolism; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism*; D002951:Citrates / Q000097:blood / Q000378:metabolism; D003624:Darkness; D003847:Deoxyglucose / Q000378:metabolism; D003576:Electron Transport Complex IV / Q000378:metabolism; D005947:Glucose / Q000378:metabolism*; D007700:Kinetics; D008928:Mitochondria / Q000201:enzymology; D010758:Phosphorus / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012016:Reference Values; D012279:Rickets / Q000097:blood / Q000378:metabolism*; D013574:Synaptosomes / Q000187:drug effects / Q000378:metabolism*; D014808:Vitamin D Deficiency / Q000097:blood / Q000378:metabolism*
D002951:Citrates; D010758:Phosphorus; D003847:Deoxyglucose; D003576:Electron Transport Complex IV; D000110:Acetylcholinesterase; D002117:Calcitriol; D005947:Glucose; D002118:Calcium