This protein binds to various endogenous compounds including long-chain fatty acids, steroids, and l-tryptophan [9].
Human serum albumin (HSA) is the most abundant protein in blood plasma, having high affinity binding sites for several endogenous and exogenous compounds.
The uridine 5'-diphospho-glucuronosyltransferase (UGT) genes encode enzymes inactivating several endogenous and exogenous compounds, including sex hormones [ 7].
Conversely, in several neurodegenerative diseases, endogenous compounds present in the extracellular space lead to a chronic activation of microglia [ 1].
CES1 is a major hydrolase in the human liver that is involved in the metabolism of several drugs and endogenous compounds.
TRXR1 and TRXR2 catalyse several reductions of both exogenous and endogenous compounds and they may play a role in the protection against cell growth and cell transformation (Mustacich and Powis, 2000).
Regarding the biological characteristics of the xenobiotic substrates of OCT1, this transporter is involved in the uptake of several toxins (Table 1) as well as endogenous compounds (Table 2).
Several Ca2+-permeable channels are activated by stimuli that freely cross membranes: capsaicin and related endogenous compounds are lipophilic and activate TRPV1 (75), and several TRP proteins (TRPV1−4, TRPM2, TRPM8, and TRPA) are activated by changes in temperature (76).
CYP enzymes are a superfamily of hemoproteins that metabolize endogenous compounds and foreign substances (xenobiotics) in several organisms, including mammals [ 27].
This gene is a member of the CYP2C family [ 23] and genes of this family encode monooxygenases that catalyse several reactions involved in the metabolism of drugs and endogenous compounds.
