The breakdown of urea in cats not secreting gastric juice

Abstract

Roberts &; Whelan (1951) have shown that this enzyme, when purified, has no action on maltose.We are not at this stage particularly concemed with differences between 'caries active' and 'caries inactive' groups of subjects. We also realize that the present DMF number is not necessarily an indication of the present caries activity. Nevertheless, certain interesting observations can be made. In group I (low DMF) fructose is metabolized at a significantly lower rate than any of the other sugars. There are also significant differences in the rates of oxidation of maltose and sucrose, and of maltose and glucose. There is no such difference in the case of glucose and sucrose. In group II (high DMF) the only conclusion which can be drawn is that fructose is metabolized at a lesser rate than the other three sugars. Our results therefore suggest that the pattern of utilization of different sugars by group I subjects differs from that of group II subjects. It is, however, unwise to deduce more from these observations on so few subjects. SUMMARY 1. The salivary flora metabolize fructose at a significantly lower rate than glucose, maltose, or sucrose.2. Subjects with a comparatively low DMF number (number of teeth decayed, missing or filled) also show differences in oxidation rate between glucose and maltose, and between sucrose and maltose, but not between sucrose and glucose.3. Subjects with a high DMF number did not show the differences enumerated in paragraph 2.Although Luck (1924a, b) had shown urease to be present in the stomachs of a wide variety of animals, urea was until recently regarded as solely an endproduct of mammalian nitrogen metabolism.

Gastrointestinal urease in man. I. Activity of mucosal urease.

“…Recently, Fleshler and Gabuzda (1965) have accumulated indirect evidence of mucosal urease activity in the adult human stomach. However, others have interpreted evidence from several species, including man, to indicate only a bacterial origin of urease in the gut (Kornberg and Davies, 1955;Thomson and Visek, 1963). The results of the present studies and those from a concurrent investigation (Evans, Aoyagi, and Summerskill, 1966) are consistent with contributions from both bacteria and the mucosa to gastrointestinal tract urease activity in man.…”

“…Urease specific activity was found throughout the gut mucosa, the amount declining in a gradient from Luck (1924) reported the presence of mucosal urease in the canine stomach, extensive studies (Kornberg and Davies, 1955) in animals have shown variation in the location and amount of the enzyme in the gut of different species as well as within the same species. Our results in humans showed less inconsistency, except for the relatively wide range of gastric mucosal urease activity.…”

“…Both bacteria (Kornberg and Davies, 1955) and mucosal cells (Conway et al, 1959) have been proposed as the site of gut urease activity in animals. Conway et al (1959) presented extensive evidence that gastric urease in the mouse is located in the epithelial cells, and the enzyme has been identified in the mitochondrial and soluble subcellular fractions of the mucosa of the mammalian stomach (Lind and Martinson, 1964).…”

“…Urease, which produces ammonia by hydrolysis of urea, may originate from either the mucosa or the bacterial flora of the gut in animals (Conway, FitzGerald, McGeeney, and Geoghegan, 1959;Dintzis and Hastings, 1953;Kornberg and Davies, 1955;Kornberg, Davies, and Wood, 1954); findings in man pertaining to mucosal urease activity are scanty (FitzGerald and Murphy, 1950;Fossel, 1948) "This investigation was supported in part by research grant AM-06908 from the National Institutes of Health, Public Health Service. or inferential (Rappoport and Kern, 1963) and liable to conflicting interpretations (FitzGerald and Murphy, 1950;Lieber and Lefevre, 1959;Visek and Thomson, 1964).…”

Utilization of Diammonium Citrate by Adult Rats

“…The N-balance of the two groups increased concomitantly with body weight gain and almost reached a plateau on the 5th day for both diets. One rat on the DAC diet 21 % during the experimental period. These result indicated that DAC_ 15 N incorporated into the NPN fraction was twice in concentrations as much as that into the PN fraction, but the amount of I5N incorporated into protein-N was twice as much as that incorporated into the NPN fraction and the incorpo-incorporation into the viscera was about twice as high as that into the carcass at least until the 48th hr.…”