Vitamin K deficiency reduces testosterone production in the testis through down-regulation of the Cyp11a a cholesterol side chain cleavage enzyme in rats

Biochim Biophys Acta. 2006 Oct;1760(10):1482-8. doi: 10.1016/j.bbagen.2006.05.008. Epub 2006 Jun 6.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alkyl and Aryl Transferases / genetics
  • Animals
  • Carboxy-Lyases / genetics
  • Cholesterol Side-Chain Cleavage Enzyme / genetics*
  • Down-Regulation
  • Farnesyltranstransferase / genetics
  • Hydroxymethylglutaryl CoA Reductases / genetics
  • Intramolecular Transferases / genetics
  • Male
  • Oligonucleotide Array Sequence Analysis
  • Rats
  • Testis / metabolism*
  • Testosterone / biosynthesis*
  • Vitamin K / metabolism
  • Vitamin K Deficiency / genetics
  • Vitamin K Deficiency / metabolism*


  • Vitamin K
  • Testosterone
  • Hydroxymethylglutaryl CoA Reductases
  • Cholesterol Side-Chain Cleavage Enzyme
  • Alkyl and Aryl Transferases
  • Rab geranylgeranyltransferase
  • Farnesyltranstransferase
  • Carboxy-Lyases
  • pyrophosphomevalonate decarboxylase
  • Intramolecular Transferases
  • lanosterol synthase