Differences are due to higher rates of metabolism by male rat liver microsomes. The enzyme works equally well with either epoxide as substrate on rat liver microsomes. NAS has been shown to protect against lipid peroxidation in microsomes and mitochondria. Regucalcin is localized in the cytoplasm, mitochondria, microsomes and nucleus. These metabolites are also found after oxidation with rat hepatic microsomes "in vitro". RGPR-p117 is present in the plasma membranes, cytoplasm, mitochondria, microsomes and nucleus of the cells. The S9 fraction is easier to prepare than purified microsomes. In human hepatic microsomes, the formation of these metabolites is regulated by CYP3A4. In this way, cytochrome P450 in microsomes is concentrated and isolated. MC is metabolized by rat liver microsomes into oxygenated forms which alkylate DNA. However, their functional effect was not confirmed in human liver microsomes. In liver microsomes, this enzyme is involved in an NADPH-dependent electron transport pathway. In contrast to R7, R13 is readily hydrolyzed into 7,8-DHF in human liver microsomes. Ampyrone stimulates liver microsomes and is also used to measure extracellular water. Microsomes can be concentrated and separated from other cellular debris by differential centrifugation.