The effect of stress on serum transaminase activity in the rat

Evaluation of Variability across Rat Acute Oral Systemic Toxicity Studies

Regulatory agencies rely upon rodent in vivo acute oral toxicity data to determine hazard categorization, require appropriate precautionary labeling, and perform quantitative risk assessments. As the field of toxicology moves toward animal-free new approach methodologies (NAMs), there is a pressing need to develop a reliable, robust reference data set to characterize the reproducibility and inherent variability in the in vivo acute oral toxicity test method, which would serve to contextualize results and set expectations regarding NAM performance. Such a data set is also needed for training and evaluating computational models. To meet these needs, rat acute oral LD₅₀ data from multiple databases were compiled, curated, and analyzed to characterize variability and reproducibility of results across a set of up to 2441 chemicals with multiple independent study records. Conditional probability analyses reveal that replicate studies only result in the same hazard categorization on average at 60% likelihood. Although we did not have sufficient study metadata to evaluate the impact of specific protocol components (eg, strain, age, or sex of rat, feed used, treatment vehicle, etc.), studies were assumed to follow standard test guidelines. We investigated, but could not attribute, various chemical properties as the sources of variability (ie, chemical structure, physiochemical properties, functional use). Thus, we conclude that inherent biological or protocol variability likely underlies the variance in the results. Based on the observed variability, we were able to quantify a margin of uncertainty of ±0.24 log₁₀ (mg/kg) associated with discrete in vivo rat acute oral LD₅₀ values.

BioActivities of Coturnix japonica (quail) egg yolk and albumen against physiological stress

Cold and immobilization stressors can generate oxidative stress as well as skeletal muscle fatigue. Free radicals cause oxidative degradation of lipids, proteins, nucleic acids, and carbohydrates molecules thereby compromising cell integrity and function. Coturnix japonica (quail) egg had been described as being very functional biochemically, due to the essential biomolecules it contains in very regulated quantity. This study was designed to evaluate the in vitro antioxidant activity of extracts of quail egg yolk and the albumen. The assessment of the antioxidant potentials was typified using the total antioxidant capacity, and ABTS, DPPH (1-diphenyl-2-picrylhydrazyl) and hydroxyl radicals scavenging activities. Others are reducing power, metal chelating and lipid peroxidation inhibition activities. The antistress activities of quail egg yolk and albumen were evaluated on hepatopathic enzymes as well as endogenous antioxidant enzymes. The total antioxidant activities of the yolk extract (YE) and the albumen extracts (AE) were, respectively, 186.57 ± 6.441 mg/g and 172 ± 10.690 mg/g AAE (Ascorbic Acid Equivalent). The YE exhibited significant, potent and appreciable antioxidant activities than AE in a concentration-dependent manner. The study confirmed that quail egg yolk contained highly antioxidative bioactive compounds not present in albumen, contributing to its (yolk) overall antioxidant and anti-inflammatory (antistress) properties, thus necessitating their (albumen and yolk) beneficial effects in the management of oxidative and inflammatory conditions.

Involvement of oxidative stress in increases in the serum levels of various enzymes and components in rats with water-immersion restraint stress

The plasma or serum levels of various enzymes and components are known to increase in rats with water-immersion restraint stress (WIRS). We examined whether oxidative stress is involved in increases in the serum levels of various enzymes and components in rats with WIRS. Rats were exposed to WIRS for 6 h after oral administration of vitamin E (VE) (50 or 250 mg/kg). Rats with WIRS had increased serum alanine aminotransferase, aspartate aminotranseferase, lactate dehydrogenase, creatine kinase, urea nitrogen, creatinine, glucose, corticosterone, adrenocorticotropic hormone and lipid peroxide (LPO) levels, increased kidney and heart VE levels, decreased skeletal muscle VE level, and increased LPO levels in all tissues studied. Pre-administered VE (50 or 250 mg/kg) attenuated the increased serum alanine aminotransferase, aspartate aminotranseferase, lactate dehydrogenase, creatine kinase, urea nitrogen, creatinine, and LPO levels, the decreased skeletal muscle VE level, and the increased LPO levels in all tissues studied more effectively at its higher dose than at its lower dose. However, either dose of the pre-administered VE did not affect the increased serum glucose, corticosterone, and adrenocorticotropic hormone levels. These results suggest that oxidative stress is involved in increases in the serum levels of various enzymes and components in rats with WIRS.

Serum enzymes levels and influencing factors in three indigenous Ethiopian goat breeds

Serum enzymes were studied in 163 apparently healthy goats from three indigenous goat breeds of Ethiopia. The effect of breed, age, sex and season on alanine aminotransferase (ALT) / glutamic pyruvic transaminase (GPT), aspartate aminotransferase (AST) / glutamic oxalacetic transaminases (GOT), alkaline phosphatase (ALP) and acid phosphatase (AcP) levels was assessed. The mean serum enzymes levels of the indigenous Arsi-Bale, Central Highland and Long-eared Somali goat breeds ranged from 14.0-20.2 iu L(-1) for ALT/GPT, from 43.2-49.3 iu L(-1) for AST/GOT, from 83.7-98.8 iu L(-1) for ALP, and from 2.99-4.23 iu L(-1) for AcP, were within the normal range for goats elsewhere. Breed had significant influence on AST/GOT values. Sex had significant effect on ALT/GPT for Arsi-Bale goats with higher values in males than females. Age was significant on all serum enzymes studied in the Arsi-Bale goats and on ALP in the Central Highland goats. Season had significant influence on all serum enzymes except for ALT/GPT in the Arsi-Bale goats. The serum enzyme levels of these indigenous goat breeds can be used as normal reference values for Ethiopian goat breeds adapted to similar agro-ecology and production system.