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Liver enzyme induction by 1,1,1-trichloro-2,2-bis-(p-chlorophenyl)ethane (DDT) is accompanied by an increase in the specific activity of elongation factor 1.

ABSTRACT: Homogenates of liver were obtained from control rats and from rats that had received DDT [1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane]. The postmicrosomal supernatant fractions were used for the purification of elongation factor 1 by hydroxyapatite chromatography and phosphocellulose chromarography. The amount of binding factor present was essentially the same for both groups of animals, but the specific activity, as measured by the binding assay, was about twice as high in the DDT-treated preparations. After sucrose-gradient sedimentation, the difference in specific activity was found to reside in the low-molecular-weight (50000) form of elongation factor 1. The implications of an increased reactivity of elongation factor 1 during the induction of membrane enzymes are discussed.

SUBMITTER: Young ET

PROVIDER: S-EPMC1185721 | biostudies-other | 1978 Jun

REPOSITORIES: biostudies-other

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Project description:BackgroundAlthough preconception 1,1,1-trichloro-2,2,bis(p-chlorophenyl)ethane (DDT) exposure and B-vitamin deficiencies have each been shown to negatively affect human reproductive outcomes, little is known about their joint effect.ObjectiveWe sought to examine whether B-vitamin sufficiency protects against adverse effects of DDT on clinical pregnancy (CP) and subclinical early pregnancy loss (EPL).DesignWe measured preconception concentrations of plasma B vitamins (vitamin B-6, vitamin B-12, and folate) and serum total DDT [sum of p,p' and o,p' isomers of DDT and 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene] in 291 nulligravid women from Anhui, China, who were studied in 1996-1998. The women were followed prospectively from the time they stopped contraception until CP (gestational age ≥42 d) or 12 mo (whichever occurred first). EPL was identified by using daily urinary human chorionic gonadotropin. The women were categorized according to B-vitamin status (deficiency compared with sufficiency) and DDT concentration (high compared with low).ResultsOf 291 study women, a total of 385 conceptions (31% of which ended in EPL) and 265 CPs occurred. Compared with women with adequate B-vitamins and low DDT, incidence rates of CP were reduced in women with B-vitamin deficiency and a high DDT concentration (P < 0.05 for all). Most notably, in women with sufficient vitamin B-12, DDT was not associated with the incidence of CP; in contrast, in women with vitamin B-12 deficiency, high DDT was associated with a lower incidence of CP (HR: 0.44; 95% CI: 0.23, 0.84); and the test for interaction was significant (P < 0.05). The odds of EPL decreased by 45% (95% CI: 21%, 62%) for each interquartile distance increase in folate in women with high DDT concentrations, and the test for interaction was significant (P = 0.006).ConclusionsOur results provide suggestive evidence that vitamin B-12 and folate sufficiency may help protect against adverse reproductive effects of DDT exposure. Additional studies are needed to confirm our findings.

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Liver enzyme induction by 1,1,1-trichloro-2,2-bis-(p-chlorophenyl)ethane (DDT) is accompanied by an increase in the specific activity of elongation factor 1.

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