Oral administration of uridylic acid increases plasma leptin, but suppresses glucose and non-esterified fatty acid concentrations in rats.

Nucleic acids have been known to have biological effects on the digestive and immune systems, although less attention has been paid to the action on metabolism. In the present study, in order to investigate the effects of oral ingestion of uridylic acid (5'-uridine monophosphate, 5'-UMP) on hormonal and metabolic levels, we measured changes in the plasma concentrations of leptin, insulin, glucose, non-esterified fatty acids (NEFA), weights of the liver and abdominal fat and fat accumulation in the liver and M. gastrocnemius in male rats. Intragastric administration of 5'-UMP via a stomach tube at a dose of 44 mg/day for 7 days slightly (P=0.098) blunted the body weight gain without causing a significant change in food intake. The administration significantly reduced the plasma concentrations of glucose (P=0.004) and NEFA (P=0.004), whereas it significantly increased (P=0.03) plasma leptin concentration. The weights of perirenal (but not epididymal) fat (P=0.083) and the liver (P=0.061) were slightly increased. The triacylglyceride concentration in M. gastrocnemius was slightly increased (P=0.097), although the muscle weight was not significantly changed (P=0.197). In summary, acute oral administration of 5'-UMP was effective in the rat in reducing plasma concentrations of glucose and NEFA, an effect that was accompanied by an elevated plasma leptin concentration.

Effects at early stage of life of elevated milk replacer feeding on growth rate, plasma IGF-I concentration and intestinal nutrient transporter expression in Holstein bull calves.

In order to evaluate the effects of an elevated amount of modified milk replacer on body weight, daily gain, starter intake, plasma endocrine parameters and expression of nutrient transporters in small intestinal epithelia, Holstein bull calves (n=24) were fed for 60days either with the usual amount of 24% crude protein (CP) and 20% fat milk (CF) replacer (C group), or with a double amount of a modified milk replacer of 28% CP and 16% CF (E group). Body weight from D20 to D60 and daily gain before D40 was greater or tended to be greater for the E group than the C group. Plasma concentrations of insulin-like growth factor-1 (IGF-I) and insulin were greater for the E group than the C group on D28 but not on D56, without changing plasma growth hormone levels. Gene expression for sodium-dependent glucose transporter 1 and fatty acid translocase (CD36) was altered in day- and intestine-dependent manners. From these findings, we conclude that an elevated intake of milk replacer given up to 40days old is sufficient to enhance body weight, which may be associated with increased plasma IGF-I concentrations, in Holstein bulls.

Effects of 5'-uridylic acid feeding on postprandial plasma concentrations of metabolites and metabolic hormones in pre-weaning goats.

5'-Uridylic acid (UMP), which is present at high concentrations in cow's colostrum, has been shown to cause a reduction in increased plasma levels of insulin and glucose after ingestion of milk replacer in pre-weaning calves. However, the precise mechanisms of UMP action have not been investigated, and its action has not been investigated in other pre-weaning ruminants. In order to demonstrate whether UMP causes changes in postprandial metabolic and hormonal parameters in pre-weaning goats, 11 Saanen kids were given milk replacer (twice a day) without (n = 5) or with (n = 6) UMP (1 g for each meal, 2 g/day for each head) for 14 days. Analysis of blood samples taken in the morning of day 14 demonstrated that the feeding of milk replacer with UMP abolished the significant changes in postprandial plasma glucose, NEFA, GH and insulin concentrations induced by feeding of milk replacer alone, and demonstrated a tendency to increase IGF-I levels. However, there was no significant difference between the two groups at any sampling time. We conclude that UMP feeding with milk replacer showed a tendency to blunt the postprandial changes in levels of some plasma metabolites and hormones that are induced by replacer alone in pre-weaning goats.