Effects on metabolic activity

Lorber, P. and Muller, W. H. 1980. Volatile growth inhibitors produced by Salvia leucophylla. effects on metabolic activity in mitochondrial suspensions. Comp. Physiol. Ecol. 5, 68-75... 

Isodesmic reactions 2 and 3 were calculated as a measure of the relative ease of formation of the aza-epoxides, in order to obtain some insight as to the effect of nitrogen atom on metabolic activation of aza-PAHs. It was presumed that formation of the epoxides is not as relevant as carbocation formation in determining the relative reactivities of Phe, BhQ and BfQ, because almost no energy differences were observed for the isodesmic reactions involving these compounds. 

Mehorta and coworkers (1989) observed that isolated fractions of brain and heart cells from rats orally administered 0.5-10 mg endrin/kg showed significant inhibition of Ca+2 pump activity and decreased levels of calmodulin, indicating disruption of membrane Ca+2 transport mechanisms exogenous addition of calmodulin restored Ca+2-ATPase activity. In vitro exposure of rat brain synaptosomes and heart sarcoplasmic reticuli decreased total and calmodulin-stimulated calcium ATPase activity with greater inhibition in brain preparations (Mehorta et al. 1989). However, endrin showed no inhibitory effects on the calmodulin-sensitive calcium ATPase activity when incubated with human erythrocyte membranes (Janik and Wolf 1992). In vitro exposure of rat brain synaptosomes to endrin had no effect on the activities of adenylate cyclase or 3, 5 -cyclic phosphodiesterase, two enzymes associated with synaptic cyclic AMP metabolism (Kodavanti et al. 1988). 

Brimer PA, Tan EL, Hsie AW. 1981. Effect of metabolic activation on the mutagenicity and cytotoxicity of ethylene dibromide in the Chinese hamster ovary hypoxanthine guanine phosphoribosyl transferase [Abstract]. Environ Mutagen 3 317-318. 

Tumor prevention. The effect of kernel fiber on metabolic activity of intestinal and... 

In addition to its effects on the activity of existing enzymes, insulin also regulates the expression of as many as 150 genes, including some related to fuel metabolism... 

However, if one accepts the hypothesis that only microbially promoted processes are occurring, it becomes necessary to explain the approximately linear dependence of the oxidation rate on 02 partial pressure as a conveniently exact effect on metabolic reaction rates. Ross and Bartlett (76) suggested that oxidation of Mn2+ is initiated by bacteria but that subsequent reaction is dominated by abiotic autocatalytic processes, once catalytically active colloids and particles are formed in sufficient numbers. 

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