Fate of Nitrate and Nitrite in Saliva and Blood of Monkey Administered Orally Sodium Nitrate Solution, and Microflora of Oral Cavity of the Monkey

Fate of nitrate and nitrite in saliva of monkey was investigated by use of five monkeys (2.5-5.0kg) which were force-fed by a stomach tube with 4, 20, 40mg/kg of body weight of sodium nitrate solution at the ten-days intervals. As the results of this preliminary investigation, the monkeys could be grouped three different converters such as very good (M1), good (M2 and M3) and poor converter (M4 and M5). To obtain more detail information about the reduction of ingested nitrate, further investigation was carried out on the good converter (M1), and the two poor converters (M4 and M5) of monkey as used for control. All monkeys used in this experiment were force-fed with 100mg/kg of sodium nitrate solutionby the stomach tube. Concentration of nitrate and nitrite in blood and saliva were successively calculated by the chemical procedure. Paralleled with this experiment, comparative survey for microflora of oral cavity of the monkeys was also conducted. Results of these studies were summarized as follows: 1) Nitrate concentration of blood in all the monkey tested peaked at 7hr after ingestion showing 180ppm. In the good monkey (M1), about 70ppm of the concentration was maintained for 48hr after administration. 2) Salivary concentration of nitrate in the good monkey showed in maximum concentration of 800ppm after 7hr, and the salivary concentration of nitrate was always kept in higher than that in blood. In contrary, the poor monkeys indicating rather lower concentration of nitrate in blood was observed. 3) Salivary concentration of nitrite in the good monkey indicated that a maximum concentration was 30ppm and 10-20ppm of nitrite was maintained in saliva for over 24hr. In the poor monkeys, however, no apparent correlation between ingestion of nitrate and formation of nitrite in saliva was observed. 4) A total count of bacteria and molds in oral cavity of the good monkey always showed a greater number of microbes than that of the poor monkeys. Streptococcaceae, Peptococcaceae and Bacteroidaceae were predominantly isolated from oral cavity of the good monkey. Of which, Bacteroides melaninogenicus was mostly common species among the microflora. Nitrate reducing species of bacteria belonging anaerobic bacteria, i. e., Bacteroidaceae and Veillonella seemed to be indigenous species in mouth of the good monkey.