Mercapturic acid formation in the developing rat

1. Young female rats dosed with 1-bromo[1-14C]propane excrete the same metabolites as adult females but in different relative proportions. Propylcysteine was detected as one of the metabolites in rats of all ages studied but represented a higher proportion of the total metabolites excreted in rats aged 5 and 11 days. 2. Hepatic GSH-S-alkytransferase activity was low in females at birth increasing up to the age of about thirty days. No activity was detected in the livers of the males at birth and up to 6 days of age; thereafter the level of activity increased up to 35-40 days. 3. Propylcysteine was excreted as prophylmercapturic acid and propylmercapturic acid sulphoxide by female rats of all ages. The amount of sulphoxide excreted relative to mercapturic acid excreted was higher in rats up to the age of 16 days than in older animals.

Studies in vitro on the effects of 1H,2H,4H(5H)-octafluorocyclohexane and 1H,4H(2H)-nonafluorocyclohexane on enzymes and organelles

A comparison has been made of the effect of 1H,2H,4H(5H)-octafluorocyclohexane, which is highly toxic (LD(50) 17mg./kg. in rats), and of 1H,4H(2H)-nonafluorocyclohexane, which is relatively non-toxic (LD(50)>440mg./kg. in rats), on the respiration of rat liver homogenates and mitochondria in vitro. 1H,2H,4H(5H)-Octafluorocyclohexane strongly inhibited the respiration of both homogenates and mitochondria, but neither compound had any significant effect on glycolysis or on glutamate dehydrogenase or NADH-cytochrome c reductase activity. 1H,2H,4H(5H)-Octafluorocyclohexane, however, caused a very marked inhibition of cytochrome oxidase activity, causing an almost complete lesion in this region of the respiratory chain. 1H,4H(2H)-Nonafluorocyclohexane was without effect in this respect. A marked decrease in turbidity of mitochondrial suspensions at 520nm. was caused by addition of both compounds, the effect being greater with 1H,2H,4H(5H)-octafluorocyclohexane. ATP, Mg(2+) and bovine serum albumin did not reverse these changes. Mitochondrial adenosine triphosphatase activity was increased twofold by the toxic compound, but only slightly by the non-toxic compound. Electron-microscopic examination of mitochondria treated with 1H,2H,4H(5H)-octafluorocyclohexane revealed gross morphological damage, whereas the effect of 1H,4H(2H)-nonafluorocyclohexane appeared to be merely to cause swelling. The results obtained account, to some extent at any rate, for the toxic effects of 1H,2H,4H(5H)-octafluorocyclohexane.