The effects of the stress caused by experimental procedures on alanine aspartate, glutamate and glutamine in rat liver

Abstract

Rats were stressed by intravenous injection, tail-warming or moderate restraint for 30s, i.e. by stresses imposed by normal handling during experiment. Liver glutamate concentrations were greatly affected. The results were substantially the same in two varieties of rat (Wistar and Sprague-Dawley), in two laboratories, in experiments carried out by two sets of workers, and after all three stresses. The following detailed results refer to Wistar rats. 1. In starved rats at 20 degrees C and 30 degrees C and in post-absorptive rats at 20 degrees C stress by injection raised liver glutamate concentrations from 1.54, 1.57 and 1.88mumol/g wet wt. 30s after injection to 3.4, 2.7 and 3.6mumol/g wet wt. respectively a few minutes later. In starved rats at 20 degrees C the concentration then fell slowly to 2.3mumol/g wet wt., in starved rats at 30 degrees C it remained steady, and in post-absorptive rats at 20 degrees C it rose slowly to about 4.3mumol/g wet wt. The final values seemed fairly steady and corresponded to an ;alert' state. 2. In starved rats at 20 degrees C anaesthesia, with or without injection or cannulation during it, raised glutamate concentrations to the ;alert' values, which were maintained for 2-3h. 3. Liver alanine concentration in post-absorptive rats initially fell from 1.5 to 0.8mumol/g, and then stayed fairly constant. 4. Aspartate and glutamine concentrations altered only in starved rats, and proportionately much less than those of glutamate. 5. The necessity for knowing the time-dependence of glutamate concentrations after experimental handling is emphasized. 6. There is no wholly satisfactory explanation of the observations.

Plasma, Erythrocyte and Human Milk Levels of Free Amino Acids in Lactating Women Administered Aspartame or Lactose

“…3). This most likely is due to either the orange juice vehicle, or the stress of blood sampling ( 12). Similar ef fects were seen after both aspartame (34 mg/kg) and aspartate (13 mg/kg body weight) loading in previous studies (7).…”

The effects of stress and injury on the activity of phosphoenolpyruvate carboxykinase in the liver of the rat

“…Food was removed at 09:00 h on the day of experiment, when rats were taken from the holding room to the laboratory and weighed (range 230-260 g). The stress of such 'handling' alters liver metabolism (Heath et al, 1971) and increases catecholamines transiently (Kvetniansky, 1980;Da Prada et al, 1980), and experiments were not started for at least 1 h to allow these effects to subside. Ambient temperatures during experiments were 20-22°C, except for rats under a4-adrenergic blockade, for which it had to be 2°C higher to maintain core temperatures in uninjured animals.…”

[14C]bicarbonate fixation into glucose and other metabolites in the liver of the starved rat under halothane anaesthesia. Metabolic channelling of mitochondrial oxaloacetate

“…Metabolites in cuvette contents were separated in the same system, when only 25ml of 5mM-HCl was needed to elute lactate.] Amino acids were eluted from the AG50-X8 column with 1 M-NH3, and fractions containing alanine, aspartate and glutamate were separated as described by Heath et al (1971). The 'alanine' fraction contained all the other neutral amino acids.…”