Tissue phylloquinone and menaquinones in rats are affected by age and gender

Phylloquinone and ten menaquinones (MK-I-MK-IO) were measured in liver and eight extrahepatic tissues from male and female rats at 3, 12 and 24 mo of age. Phylloquinone and menaquinones showed characteristic tissue distributi on. In liver, all 11 vitamers of vitamin K:assayed were present in varying concentrations with phylloquinone and MK-6 the major forms. The only forms of vitamin K found in extrahepatic tissues were phylloquinone, MK-4 and MK- 6. Brain contained only MK-4 and traces of phylloquinone. No significant ge nder difference was observed for phylloquinone except in heart at 3 mo of a ge (P less than or equal to 0.05). In heart, kidney and brain, MK-4 was sig nificantly higher in females than in males (P less than or equal to 0.05). A similar gender effect was seen in kidney and lung for MK-6 (P less than o r equal to 0.05). With age, hepatic phylloquinone and MK-6 significantly in creased (P less than or equal to 0.05), whereas MK-4 was unchanged. In extr ahepatic tissues, MK-4 decreased with age in heart and kidney of males and females, and in lung and cerebellum of males (P less than or equal to 0.05) . MK-6 decreased with age in all extrahepatic tissued tested (P less than o r equal to 0.05). The results suggest that in extrahepatic tissues, certain menaquinones may be the predominant form of vitamin K. The specific tissue distribution and the general decline of MK-4 and MK-6 in extrahepatic tiss ues during aging suggest a vitamin K tissue dynamic that is affected not on ly by diet, but also by gender, age and the specific roles of phylloquinone , MK-4 and MK-6 in metabolism. All of these factors must be taken into acco unt in establishing the nutrient requirement for vitamin K.