Effects of Menatetrenone on the Decrease in Calcium Balance Induced by Vitamin K-Deficient Diet and Sodium Loading in Rats.

Abstract

ABSTRACT-The effects of menatetrenone (2-methyl-3-tetraprenyl-1,4-naphthoquinone, MK-4) on cal cium balance were studied in male Sprague-Dawley rats. Experiment 1: Rats in metabolic cages that were fed a vitamin K-deficient diet and injected daily with latamoxef (100 mg/kg, i.p.) were either treated or untreated with MK-4 for 7 days. Daily food intake, urine volume and feces weight were determined, and calcium concentration in these samples was measured. Calcium balance was calculated as the difference between calcium intake and urinary and fecal calcium excretion. Cumulative calcium balance in the vitamin K-deficient group treated with latamoxef was lower than that in normal rats; this balance was significantly improved by MK-4 (1 and 10 mg/kg, s.c.) administered for 7 days. Experiment 2: Rats were fed a vitamin K-deficient diet containing 4.6°1o sodium chloride for 6 weeks. MK-4 was administered as a dietary supple ment. Forty-eight-hour calcium balance, determined once a week, was significantly reduced compared with that of normal rats after 3 and 5 weeks; the balance was restored dose-dependently by MK-4 administration (1 and 10 mg/kg). Experiment 3: Rats were subjected to the same experimental conditions as experiment 2 for 6 weeks, and intestinal calcium transport was determined using an everted gut-sac technique. Calcium transport was reduced by the high sodium, vitamin K-deficient diet, and this reduction was restored by MK 4 administration (10 mg/kg). These results suggest that MK-4 improves the reduced calcium balance by increasing intestinal calcium absorption in these rats.

Effects of Vitamin K2 (Menatetrenone) on Calcium Balance in Ovariectomized Rats

“…These findings were consistent with the report of Arjmandi et al (26), and O'Loughlin and Morris (27). We have already reported that vitamin K 2 improved a decrease in intestinal Ca transport which was induced by sodium loading in rats (17). In this study, however, the intestinal Ca transport was higher in the vitamin K2 administration groups than in the OVX-control group, but not to a significant extent.…”

“…The S/M ratio in the shamtreatment group was 3.37. In this study, in contrast, the S/ M ratio in the sham-treatment group was lower (1.18) than that in our previous study (17). This result is considered due to the use of very aged (29-week-old) Fischer rats.…”

“…In vitro studies indicated that vitamin K 2 inhibits bone resorption in an organ culture system, inhibits the osteoclast-like cell formation in bone marrow culture and co-culture systems and enhances mineralization in human osteoblasts (14 -16). Moreover, we previously reported that vitamin K2 improves the poor Ca balance and intestinal Ca absorption induced by sodium loading in rats (17).…”

Comparative Effects of Vitamin K and Vitamin D Supplementation on Calcium Balance in Young Rats Fed Normal or Low Calcium Diets

“…Kobayashi et al (3) showed that vitamin K supplementation in severe calcium/ magnesium-deficient rats improved the abnormal decreases in serum calcium and magnesium levels and abnormal increases in serum PTH level and renal cal cium concentration. Tomiuga et al (6) showed that vitamin K supplementation in vitamin K-deficient and sodium-loading rats prevented the reduction in intesti nal calcium absorption. Thus, vitamin K supplementa tion may have the potential to increase renal and intes tinal retention.…”

Determination of plasma Vitamin K by high-performance liquid chromatography with fluorescence detection using Vitamin K analogs as internal standards

“…In addition, several reports indicate an important role for Vitamin K in bone health. Administration of Vitamin K results in an increase in bone-mineral density and a reduction in bone resorption in humans [3][4][5][6] and rodents [7][8][9][10][11][12][13].…”