Regulation of glutathione S-transferase gene expression and activity by dietary selenium.

To determine selenium's effects on glutathione S-transferase gene expression and enzyme activity, weanling rats were fed a selenium-deficient diet, or the same diet supplemented with 0.1 (control) or 2.0 mg selenium/kg diet as sodium selenite, for 91 days. Consumption of either the selenium-deficient or high selenium diet increased activity of glutathione S-transferase, measured with 1-chloro-2,4-dinitrobenzene as substrate, compared to the control diet. Transcription of genes for glutathione S-transferase subunits was unaffected by selenium intake. Steady state levels of mRNA for glutathione S-transferase subunits were affected variably by changes in selenium intake, depending upon the tissue and subunit examined. These results suggest that the biological effects of selenium may be due in part to its regulation of gene expression for glutathione S-transferase family enzymes.

Effect of 1,3-butanediol and short chain acids in sow gestation diets on maternal plasma metabolites and fetal energy storage.

Gestating sows were fed diets in which 15% of the metabolizable energy was in the form of glucose monohydrate (control), 1,3-butanediol (BD) or an equimolar mixture of acetate and lactate (AL) in order to study the effects of ketogenic, glucogenic and lipogenic substrates on fetal energy storage. Diets were initiated on d 90 of gestation. Blood plasma was obtained from sows 2 and 8 h after feeding on d 102 of gestation. Sows receiving BD had a higher (P less than .001) concentration of beta-hydroxybutyrate (.54 vs .12, .14 mM) and a lower (P less than .05) concentration of glucose (72 vs 82, 86 mg/dl) after 8 h than sows in control or AL groups, respectively. Sows in the AL group had a higher (P less than .10) acetate concentration at 2 h, but no difference was observed by 8 h. Lactate concentration was lower (P less than .10) in AL sows when compared with those in the control group (69 vs 101 mg/dl). Two pigs/litter were killed at birth and two/litter were fasted for 36 h with blood samples obtained at 12-h intervals. Newborn pigs from AL and BS sows had more total liver glycogen than pigs derived from control sows (4.18, 4.07 vs 3.09 g, respectively); however, this difference was significant only for pigs from AL sows (P less than .10). Pigs in BD and AL groups had a higher (17 to 25%), though not significantly different, glucose concentration than controls after 24 and 36 h of fasting.(ABSTRACT TRUNCATED AT 250 WORDS)