title: [Are the receptors of 1,25-dihydroxyvitamin D3 vitamin K dependent?].
abstract: Alimentary deficiency of vitamin K in rats causes a decrease in the level of in vivo occupied nuclear 1,25 (OH)2D3 receptors in small intestinal mucosa and an 2-2.5-fold increase in the ability of cytosolic 1,25 (OH)2D3-receptor complexes to bind to heterologous DNA. The 1,25 (OH)2D3 binding by the receptors is thereby unaffected. Preincubation of kidney and intestinal cytosol of rats with the secondary K-avitaminosis induced by vitamin K antagonist with the microsomal vitamin K-dependent gamma-carboxylation system sharply decreases the binding of the 1.25 (OH)2D3-receptor complexes to DNA. In rats treated with the vitamin K antagonist in combination with a low calcium diet, the subsequent maintenance on a high calcium diet does not cause, in contrast with vitamin K-repleted animals, a sharp decrease of the level of the in vivo occupied 1,25 (OH)2D3 receptors. In vitro Ca2+ cations decrease the binding of the 1,25 (OH)2D3-receptor complexes to DNA only in vitamin K-repleted rats (ED50 = 2.5 x 10(-6) M). The existence of a vitamin K-dependent Ca-sensitive mechanism regulating the binding of the 1,25 (OH)2D3 receptor to DNA has been postulated for the first time.
authors.forename: I N
authors.initials: IN
authors.lastname: Sergeev
authors.forename: V B
authors.initials: VB
authors.lastname: Spirichev
mesh_terms: D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism; D002853:Chromatography, Liquid; D004247:DNA / Q000378:metabolism*; D007421:Intestine, Small / Q000166:cytology / Q000378:metabolism; D007668:Kidney / Q000166:cytology / Q000378:metabolism; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D018167:Receptors, Calcitriol; D011987:Receptors, Steroid / Q000187:drug effects* / Q000378:metabolism; D014812:Vitamin K / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D014813:Vitamin K Deficiency / Q000378:metabolism
chemical_list: D018167:Receptors, Calcitriol; D011987:Receptors, Steroid; D014812:Vitamin K; D004247:DNA
vernacular_title: Iavliutsiia li retseptory 1,25-digidroksivitamina D3 vitamin K- zavisimymi?