Influence of partial starvation and of acute scurvy on the free amino acids in blood plasma and muscle in the guinea-pig

Taurine Supplementation as a Neuroprotective Strategy upon Brain Dysfunction in Metabolic Syndrome and Diabetes

Obesity, type 2 diabetes, and their associated comorbidities impact brain metabolism and function and constitute risk factors for cognitive impairment. Alterations to taurine homeostasis can impact a number of biological processes, such as osmolarity control, calcium homeostasis, and inhibitory neurotransmission, and have been reported in both metabolic and neurodegenerative disorders. Models of neurodegenerative disorders show reduced brain taurine concentrations. On the other hand, models of insulin-dependent diabetes, insulin resistance, and diet-induced obesity display taurine accumulation in the hippocampus. Given the possible cytoprotective actions of taurine, such cerebral accumulation of taurine might constitute a compensatory mechanism that attempts to prevent neurodegeneration. The present article provides an overview of brain taurine homeostasis and reviews the mechanisms by which taurine can afford neuroprotection in individuals with obesity and diabetes. We conclude that further research is needed for understanding taurine homeostasis in metabolic disorders with an impact on brain function.

The effects of folate deficiency and oestradiol administration on the plasma free amino acid concentrations of the immature hen

1. Free amino acid concentrations were measured in the blood plasma of immature pullets receiving a folate-deficient diet and injected with folate and/or oestradiol, with appropriate controls. 2. Folate deficiency caused a decrease and oestradiol administration an increase in the plasma concentration of most of the amino acids studied. 3. Plasma glycine concentration increased in foliate deficiency and decreased with oestradiol treatment. 4. All the observed effects could not be readily explained in terms of the known metabolic role of folate in amino acid metabolism. 5. The results did not indicate that the role of folate in amino acid metabolism was significant in the inhibition of oestradiol-stimulated oviduct growth.

[Effect of food deprivation on various parameters of rumen juice and blood of sheep]

In order to find out how short-time denutrition changes the concentration of some substances in the rumen fluid and the blood, tests with full-grown sheep were carried out. Fodder was withheld from sheep with inserted Jarrett fistulae for 48 hours after normal feeding. After 48 hours the animals were given concentrated fodder, after 52 hours exclusively hay. From the 72nd hour onwards the animals were provided with fodder as usual. Samples of the rumen fluid and blood samples were taken at the beginning of the test, after the last normal feeding and then in the 24th, 32nd, 48th, 52nd, 56th, 72nd and 96th hour. We could find out that, during the 48-hour denutrition, the pH-value of the rumen fluid turned alkaline and the concentrations of ammonia, volatile fatty acids and lactic acid decreased. The protein metabolism underwent a rapid change in the organism. The protein content of the blood plasma decreased, above all the albumin content, as well as the concentration of glycoproteins and volatile amino acids. Among the various amino acids, the concentration of glycine increased highly, that of alanine and valine just slightly. The concentration of most amino acids decreased or--of some of them remained the same. Among the paramters that are characteristic of lipid and carbohydrate metabolism, the total content of lipids and cholesterin decreased, and so did the concentration of blood sugar, lactic acid and pyruvic acid in the blood plasma. The results indicate that short-time denutrition has a considerable influence on the rumen fermentation and the intermediary metabolism of ruminants. The quickly arising lack of energy of ruminants slows down the protein synthesis and increases the glyconeogenesis from amino acids. The tissue is supplied with energy by the mobilisation of lipids.