title: Vitamin K deficiency reduces testosterone production in the testis through down-regulation of the Cyp11a a cholesterol side chain cleavage enzyme in rats.
abstract: Vitamin K (K) is an essential factor for the posttranslational modification of blood coagulation factors as well as proteins in the bone matrix (Gla proteins). It is known that K is not only distributed in the liver and bones but also abundantly distributed in the brain, kidney, and gonadal tissues. However, the role of K in these tissues is not well clarified. In this study, we used DNA microarray and identified the genes whose expression was affected in the testis under the K-deficient (K-def) state. The expression of genes involved in the biosynthesis of cholesterol and steroid hormones was decreased in the K-def group. The mRNA levels of Cyp11a - a rate-limiting enzyme in testosterone synthesis - positively correlated with the menaquinone-4 (MK-4) concentration in the testis. Moreover, as compared to the control (Cont) and K-supplemented (K-sup) groups, the K-def group had decreased testosterone concentrations in the plasma and testis. These results suggested that K is involved in steroid production in the testis through the regulation of Cyp11a.
authors.affiliation: Laboratory of Nutrition, Graduate School of Agricultural Science, Tohoku University, Sendai 981-8555, Japan. shirakah@biochem.tohoku.ac.jp
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Shirakawa
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Ohsaki
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Minegishi
authors.forename: Naofumi
authors.initials: N
authors.lastname: Takumi
authors.forename: Kousaku
authors.initials: K
authors.lastname: Ohinata
authors.forename: Yuji
authors.initials: Y
authors.lastname: Furukawa
authors.forename: Takeo
authors.initials: T
authors.lastname: Mizutani
authors.forename: Michio
authors.initials: M
authors.lastname: Komai
mesh_terms: D019883:Alkyl and Aryl Transferases / Q000235:genetics; D000818:Animals; D002262:Carboxy-Lyases / Q000235:genetics; D002786:Cholesterol Side-Chain Cleavage Enzyme / Q000235:genetics*; D015536:Down-Regulation; D051231:Farnesyltranstransferase / Q000235:genetics; D006903:Hydroxymethylglutaryl CoA Reductases / Q000235:genetics; D019751:Intramolecular Transferases / Q000235:genetics; D008297:Male; D020411:Oligonucleotide Array Sequence Analysis; D051381:Rats; D013737:Testis / Q000378:metabolism*; D013739:Testosterone / Q000096:biosynthesis*; D014812:Vitamin K / Q000378:metabolism; D014813:Vitamin K Deficiency / Q000235:genetics / Q000378:metabolism*
chemical_list: D014812:Vitamin K; D013739:Testosterone; D006903:Hydroxymethylglutaryl CoA Reductases; D002786:Cholesterol Side-Chain Cleavage Enzyme; D019883:Alkyl and Aryl Transferases; C075607:Rab geranylgeranyltransferase; D051231:Farnesyltranstransferase; D002262:Carboxy-Lyases; C022503:pyrophosphomevalonate decarboxylase; D019751:Intramolecular Transferases; C021924:lanosterol synthase