I think pharmacogenomics of pharmagenetics could expain, at least partly, why we respond differently to exogenous hormones ( or any other drug for that matter) and why some of us have absorption issues. I don't have much time to go into details of explain further but I think this could be important. Especially because, at least in most country"s, it's now possible to take a pharmacogenomic test for certain medication.
Pharmacogenomics is the study of how genes affect a person's response to drugs. This relatively new field combines pharmacology (the science of drugs) and genomics (the study of genes and their functions) to develop effective, safe medications and doses that will be tailored to a person's genetic makeup.
Many drugs that are currently available are ?one size fits all,? but they don't work the same way for everyone. It can be difficult to predict who will benefit from a medication, who will not respond at all, and who will experience negative side effects
A brief introduction from Wiki about Cytochrome (CYP) P450 and drug- metabolisme:
CYPs are the major enzymes involved in drug metabolism, accounting for about 75% of the total metabolism.[18] Most drugs undergo deactivation by CYPs, either directly or by facilitated excretion from the body. Also, many substances are bioactivated by CYPs to form their active compounds like clopidogrel.
Drug interaction
Many drugs may increase or decrease the activity of various CYP isozymes either by inducing the biosynthesis of an isozyme (enzyme induction) or by directly inhibiting the activity of the CYP (enzyme inhibition). A classical example includes anti-epileptic drugs, such as Phenytoin, which induces CYP1A2, CYP2C9, CYP2C19, and CYP3A4.
Effects on CYP isozyme activity are a major source of adverse drug interactions, since changes in CYP enzyme activity may affect the metabolism and clearance of various drugs. For example, if one drug inhibits the CYP-mediated metabolism of another drug, the second drug may accumulate within the body to toxic levels. Hence, these drug interactions may necessitate dosage adjustments or choosing drugs that do not interact with the CYP system. Such drug interactions are especially important to consider when using drugs of vital importance to the patient, drugs with significant side-effects, or drugs with a narrow therapeutic index, but any drug may be subject to an altered plasma concentration due to altered drug metabolism.
Many substrates for CYP3A4 are drugs with a narrow therapeutic index, such as amiodarone[19] or carbamazepine.[20] Because these drugs are metabolized by CYP3A4, the mean plasma levels of these drugs may increase because of enzyme inhibition or decrease because of enzyme induction.
Interaction of other substances
Naturally occurring compounds may also induce or inhibit CYP activity. For example, bioactive compounds found in grapefruit juice and some other fruit juices, including bergamottin, dihydroxybergamottin, and paradicin-A, have been found to inhibit CYP3A4-mediated metabolism of certain medications, leading to increased bioavailability and, thus, the strong possibility of overdosing.[21] Because of this risk, avoiding grapefruit juice and fresh grapefruits entirely while on drugs is usually advised.[22]
Other examples:
Saint John's Worth a common herbal remedy induces CYP3A4, but also inhibits CYP1A1, CYP1B1.[23][24]
Tobacco smoking induces CYP1A2 (example CYP1A2 substrates are clozapine, olanzapine, and fluvoxamine)[25]
At relatively high concentrations, starfruit juice has also been shown to inhibit CYP2A6 and other CYPs.[26] Watercress is also a known inhibitor of the cytochrome P450 CYP2E1, which may result in altered drug metabolism for individuals on certain medications (e.g., chlorzoxazone).[27]
Tributyltin has been found to inhibit the function of cytochrome P450, leading to masculinization of mollusks.[28]
Goldenseal, with its two notable alkaloids berberine and hydrastine, has been shown to alter P450-marker enzymatic activities (involving CYP2C9, CYP2D6, and CYP3A4).[29]
Estradiol and Progesterone are, amongst others, metabolised by CYP3A4.
If you search of Google you will find a lot of information that will explain in more detail.
Alicess X
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Topic: Pharmacogenomic tests and absorption of hormones (Read 852 times)