Antifertility and mutagenic effects in mice from parenteral administration of di-2-ethylhexyl phthalate (DEHP)

The subcutaneous administration of 1-10 mg of undiluted di-(2-ethylhexyl)phthalate di-(2-ethylhexyl)phthalate (DEHP) to adult male ICR mice on d 1, 5, and 10 was followed by mating, one to one, with untreated adult virgin females. A single mating at d 21 resulted in a reduction in the incidence of pregnancies in the DEHP-treated groups. On the other hand, repeated matings with fresh females starting on d 2, 6, 11, 16, and 21, and at weekly intervals through 8 wk, revealed no perceptible effect of DEHP on the incidence of pregnancy. Examination of surgically exposed uteri and ovaries of pregnant females on d 13 of gestation revealed an increase in the incidence of preimplantation losses and early fetal deaths in the DEHP-treated groups; consequently, there were fewer viable fetuses per pregnancy. Mutagenic indices for DEHP, calculated as percent ratios of (1) preimplantation losses/implantations per pregnancy and (2) early fetal deaths/implantations per pregnancy, suggested a dominant lethal mutation effect in the treated mice. These effects tend to be more pronounced on the postmiotic stage of germ-cell development.

Biochemical changes in saliva of malnourished children

The protein concentration and activity of arginase enzymes in serum and saliva was estimated in a total of 94 children out of which 52 were suffering from protein-energy malnutrition (PEM) and 42 served as controls. The salivary ferritin was also estimated in 41 children (control eight and PEM 33). There was a progressive fall in serum and salivary arginase activity and levels of salivary protein and ferritin with severity of PEM. The salivary ferritin showed very significant fall even in PEM grade I. In PEM grade III the mean ferritin value was 3.28 +/- 0.75 micrograms/L as compared to 169.3 +/- 21.9 micrograms/L for normal children. The changes in salivary protein, arginase activity, and ferritin in PEM may be used in recognizing severity as well as early stage of the disease.

Interaction of di-(2-ethylhexyl) phthalate with the pharmacological response and metabolic aspects of ethanol in mice

The interactions of di-(2-ethylhexyl) phthalate (DEHP) with the pharmacological response and metabolic aspects of ethanol in mice were investigated at oral doses of DEHP of 1.5, 3.0 and 7.5 g/kg or intraperitoneal doses of 3.7, 7.5 and 18.9 g/kg, administered once or daily for 7 days. A single oral or intraperitoneal administration of DEHP resulted in a significant increase in the ethanol-induced sleeping time, associated with an inhibition of alcohol dehydrogenase activity in liver; the effect of intraperitoneal administration was significant only at the highest dose. The activities of high and low Km aldehyde dehydrogenases in mouse liver were not affected by a single dose of DEHP by either route. Repeated oral doses of DEHP produced significant reductions in the ethanol-induced sleeping time and increases in the activities of alcohol and aldehyde dehydrogenases, whereas repeated intraperitoneal doses of DEHP significantly increased the sleeping time and decreased the activity of alcohol dehydrogenase, without any perceptible effect on the activities of aldehyde dehydrogenases. In vitro studies with mouse liver preparations revealed significant inhibition of alcohol dehydrogenase activity by mono-(2-ethylhexyl) phthalate and 2-ethylhexanol and of high and low Km aldehyde dehydrogenase activities by DEHP and mono-(2-ethylhexyl) phthalate at concentrations ranging from 0.03 to 1.00 mM. In all cases, in vitro enzyme inhibition by mono-(2-ethylhexyl) phthalate was most pronounced.

Influence of sex hormones on parathion toxicity in rats: antiacetylcholinesterase activity of parathion and paraoxon in plasma, erythrocytes, and brain

Administration of parathion resulted in a greater inhibition of acetylcholinesterase (AChE) activity of plasma, erythrocytes, and brain in female rats than in male rats. No sex-related difference was observed in the antiacetylcholinesterase activity of paraoxon, an active metabolite of parathion. Gonadectomy increased the susceptibility of males but had no perceptible effect on females, resulting in comparable inhibition of AChE by parathion in both sexes. Administration of testosterone led to recovery from increased sensitivity to the antiacetylcholinesterase activity of parathion in castrated males and afforded partial protection to ovariectomized females. On the other hand, administration of estradiol further enhanced the enzyme inhibition by parathion in castrated males but had no significant effect on that in ovariectomized females. Alterations in the status of sex hormones did not affect the antiacetylcholinesterase activity of paraoxon in plasma and erythrocytes. However, inhibition of AChE activity by paraoxon was significantly higher in brains of gonadectomized rats than those of normal rats and the effect was reversible on administration of the respective sex hormones. The results indicate that testosterone plays an important role in determining parathion toxicity (as reflected by its antiacetylcholinesterase activity), probably by activating the oxidative cleavage of the insecticide into nontoxic metabolites.