1,25-Dihydroxyvitamin D3 treatment results in increased choline acetyltransferase activity in specific brain nuclei.
To better understand the role of 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] in brain function, the level of calcium-binding protein (CaBP) and the activities of choline acetyltransferase (CAT) and monoamine oxidase were measured in discrete brain nuclei of vitamin D-deficient and -replete male rats. The nuclei sampled were those in which receptors for 1,25-(OH)2D3 and/or vitamin D-dependent CaBP have been localized. Significant elevations in CAT activity were found in the arcuatemedian eminence and in the bed nucleus of the stria terminalis of rats made vitamin D replete by eight daily ip injections of 100 or 200 ng 1,25-(OH)2D3 as well as by constant intraventricular (ivi) infusion of 25 ng 1,25-(OH)2D3 for 7 days. The percent increase ranged from 12-45% and was related to the ip dose administered. Constant ivi of 2 mM CA2+ or 125 ng 25-hydroxyvitamin D3/day for 7 days did not alter CAT activity. No significant changes in monoamine oxidase or CaBP in discrete brain nuclei were observed with vitamin D repletion. Since the arcuate-median eminence of the hypothalamus is an important regulatory site in the neuroendocrine control of reproduction, serum testosterone was measured. Serum testosterone levels were abnormally low in the vitamin D-deficient animals, but increased 2- to 5-fold to normal values in those rats made vitamin D replete by constant ivi of 25 ng 1,25-(OH)2D3 or by ip injection of 100 or 200 ng 1,25-(OH)2D3. Patterns of serum LH paralleled those for testosterone. Our results suggest that 1,25-(OH)2D3 effects cholinergic activity in several discrete brain regions and may play a role in the neuroendocrine regulation of certain aspects of anterior pituitary gland function.
D000818:Animals; D001921:Brain / Q000187:drug effects / Q000648:ultrastructure*; D002112:Calcifediol / Q000494:pharmacology; D002117:Calcitriol / Q000494:pharmacology*; D002118:Calcium / Q000494:pharmacology; D002467:Cell Nucleus / Q000201:enzymology*; D002795:Choline O-Acetyltransferase / Q000378:metabolism*; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D008995:Monoamine Oxidase / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D064030:S100 Calcium Binding Protein G / Q000378:metabolism; D013739:Testosterone / Q000097:blood; D013997:Time Factors
D064030:S100 Calcium Binding Protein G; D013739:Testosterone; D007986:Luteinizing Hormone; D008995:Monoamine Oxidase; D002795:Choline O-Acetyltransferase; D002117:Calcitriol; D002112:Calcifediol; D002118:Calcium