Topic:Microsomes
Microsomes are subcellular fractions derived from fragmented endoplasmic reticulum, and they are involved in various metabolic processes in horses. These vesicular structures contain enzymes crucial for the metabolism of xenobiotics, including drugs and environmental chemicals. In equine studies, microsomes are often used to investigate the metabolic pathways and biotransformation of substances within the liver. Research in this area focuses on understanding the enzymatic activities present in equine microsomes, particularly cytochrome P450 enzymes, which are responsible for the oxidative metabolism of many compounds. This page compiles peer-reviewed research studies and scholarly articles that explore the function, enzymatic activity, and implications of microsomal metabolism in horse health and pharmacology.
The effects of aging on hepatic microsomal scaling factor and hepatocellularity number in the horse. 1. Scaling factor values for the in vitro-in vivo extrapolation of hepatic metabolic clearance for xenobiotics have not yet been determined in horses. Scaling factors were determined by comparing the total protein and or cytochrome (CYP) P450 content in microsomes and cryopreserved hepatocytes against the content in the liver. 2. Microsomal protein per gram of liver (MPPGL) and hepatocellularity number per gram of liver (HPGL) using CYP P450 content method ranged 41-73 mg/gram of liver (mean= 57 mg/gram of liver, n = 39) and 146-320 × 10 cells/g of liver (mean = 227× 10 c...
Species comparison of vitamin K1 2,3-epoxide reductase activity in vitro: kinetics and warfarin inhibition. A comparative study of vitamin K(1) 2,3-epoxide reductase (VKOR) activity in vitro was conducted across species. The apparent kinetic constants K(m app), V(max), and Cl(int app) were determined in bovine, canine, equine, human, murine, ovine, porcine, and rat hepatic microsomes. In addition to these enzyme kinetic constants, the IC(50) of warfarin for VKOR was determined in human, murine, porcine, and rat hepatic microsomes. Interspecies differences were observed when comparing the K(m app) (range, 2.41-6.46 microM), V(max) (range, 19.5-85.7 nmol/mg/min), and Cl(int app) (range, 8.2-18.4 ml/mg...