Endogenous exposure

Erkkila J, Armstrong R, Riihimaki V, et al. 1992. In vivo measurements of lead in bone at four anatomical sites long term occupational and consequent endogenous exposure. Br J Ind Med 49 631-644. 

Endogenous Exposure Estrogen, catechol estrogen-3,4-quinones... 

Swenberg et al. (2008) came to different conclusions in a review of the dose-response literature for mutations and DNA adducts, which are biomarkers of exposure. They concluded that biomarkers of exposure (DNA adducts) are usually linear at low doses down to zero (except when the chemical-induced adduct is also formed endogenously, in which case there is a plateau at the endogenous exposure level, and the adduct level of de minimus exposures below endogenous amounts will be lost in the noise of the background). In contrast, they found that biomarkers of effect... 

Exposure to estrogenic compounds through diet will differ for herbivores and carnivores, the latter being most likely to encounter endogenous steroids in their prey. Efficient uptake of steroids in mammals is illustrated by the use of the contraceptive pill, but routes of absorption in invertebrates remain to be determined. The relationship between endocrine disruption and metabolic toxicity, with reduced reproductive viability a secondary consequence of metabolic disturbance, also merits further study in invertebrate species. 

A hormonal disorder caused by the prolonged exposure to high levels of endogenous or exogenous sources of cortisol. 

Lim CB et al Reduction in the rates of protein and amino acid catabolism to slow down the accumulation of endogenous ammonia a strategy potentially adopted by mudskippers during aerial exposure in constant darkness. J Exp Biol 2001 ... 

Studies have demonstrated that one such method is to examine the effects of disinfectants on endogenous RNA-dependent DNA polymerase (i.e. reverse transcriptase) activity. In essence, HIV is an RNA virus after it enters a cell the RNA is converted to DNA under the influence of reverse transcriptase. The virus induces a cytopathic effect on T lymphocytes, and in the assay reverse transcriptase activity is determined after exposure to different concentrations of various disinfectants. However, it has been suggested that monitoring residual viral reverse transcriptase activity is not a satisfactory alternative to tests whereby infectious HIV can be detected in systems employing fresh human peripheral blood mononuclear cells. 

Although commonly formed from endogenous material, the occurrence of synovial crystals formed following environmental exposure to exogenous agents is indicated by the identification of both aluminium phosphate and aluminium silicate particulates (Netter etal., 1983, 1991). It is noteworthy in this context that arthritic symptoms have been reported following the... 

Biomarkers of exposure for inorganic and organic forms of lead are usually the measurement of total lead levels in tissues or fluids. Total lead measurements of biological media includes all metabolites and endogenous lead sources as well as any original lead-containing exposure agent. Tetraalkyl lead compounds may also be measured in the breath. 

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