Aflatoxins have also been found in humancordbloodand app arentlycanenterthedevelopingfetusinhum ans and anim als. In addition, aflatoxins have been found in human breast milk, cows milk and dairy products. Marvan andhis colleagues have experimentally studied distribution of AFB in goslings and chickens and according to AFB concen trations the organs andtissues were categorized as follows: gonads; parenchymatous organsliver and kidney; lymphopoietic organsspleen, bursa cloacalis and thymus; followed by the endocrine glands and muscles; lungs have low concentration and in brain, the lowest.Aflatoxin B is converted in the adult liver by the cytochrome P enzyme, P III AY and in the fetal liver with P III A to AFQ the major metabolite of AFB.Cytochrome P IIIA, which can both, activate and detoxicate AFB, is found.Only one of these, the, exoepoxide appears to be mutagenic and others are detoxification products.The putative AFB epoxide is generally accepted as the active electrophilic form of AFB that may attack nucleophilic nitrogen, oxygen and sulphur heteroatoms in cellular constituents. This highly reactive substance may combine with DNA bases such as guanine to produce alterations in DNA. This may be the most important product from the carcinogenic point of view.Formation of these adduc tsdisrup ts the normal working process of the cell and in the case of DNA adducts, can ultimately lead to a loss of control over cellular growth and division.Human metabolised AFB to the major aflatoxin BN guanine adducts at levels comparable to tho se in spec ies, wh ich a re su sceptib le to aflatoxininduced hepatocarcinogenicity such as the rat.<a href="http://inhibit06.online/archives/172"></a>
Presence of AFBDNA adduct was identified both in vivo and in vitro. The binding of AFB residues to DNA in vivo is essentially a linear function of dose at a given time after treatment.In circulation, aflatoxin binds with plasma proteins especially albumin to form aflatoxinalbumin adduct have elucidated the structure of the major aflatoxinalbumin adduct found in vivo.This protein adduct is a completely modified aflatoxin structure retaining only the coumarin and cyclopentenone rings of the parent compound.These adduct represent the cumulative dose of aflatoxin intake over previous weeks.The average halflife of albumin in people is about days.Therefore, an accumulated dose of aflatoxin will be present in albumin long after the dietary exposure has ceased.This is a property not found for DNA adduct because the halflife of DNA AFLATOXIN AND DNA DAMAGE adduct is about hour and then rapidly excreted in urine.Af la tox in concen tration recorded in the serum of human beings varies with the amount and du rationof afla tox in inges ted and the physiological state of the body.Both unmetabolized of aflatoxins get excreted in the urine, stool and milk also reported presence of seven different types of aflatoxins in the saliva of human beings.Aflatoxin excretedsecreted through saliva might be getting absorbed in gastrointestinal tract and passing again to the blood stream.This explains a sort of recycling of aflatoxin in the body.Aflatoxin exposure to hepatocytes in vitro caused pronounced swelling, polymorphic condition, bleb formation and lysis. When RBC suspension was treated with aflatoxin in vitro, a concentrationdependent swelling followed by lysis was observed indicating permeability alterations and membrane destabilization.