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- Olsson, U, et al.
(författare)
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Effects of selenium deficiency on xenobiotic-metabolizing and other enzymes in rat liver.
- 1993
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Ingår i: International Journal for Vitamin and Nutrition Research. - 0300-9831 .- 1664-2821. ; 63:1
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Tidskriftsartikel (refereegranskat)abstract
- The present study was undertaken to characterize effects of selenium (Se) deficiency on 16 enzymes recovered in either one or more of the subcellular fractions of rat liver (as a basis for future studies on the mechanisms underlying the observed changes). Male rats were fed a Torula-yeast based diet with 0.23 mg Se/kg or the same diet with 0.009 mg Se/kg, from weaning and for 10 weeks. Statistically significant effects of Se deficiency were the following: Se-dependent glutathione peroxidase decreased to 0.14% of the Se-adequate controls, while cytosolic glutathione transferase increased 3-fold in Se deficiency when CDNB was the substrate, but decreased significantly when trans-stilbene oxide (diagnostic for subunit 4) was used as the substrate. Cytosolic DT-diaphorase increased about 7-fold in Se deficiency. Further, DT-diaphorase in the microsomal fraction was also significantly increased in Se deficiency, as were the microsomal and mitochondrial epoxide hydrolases and microsomal glutathione transferase. Furthermore, increased activity of the peroxisomal marker enzyme catalase (P < 0.05) was noted in Se-deficient rats. It is our working hypothesis that changes in enzyme activities in Se deficiency are mainly due to changed levels of endogenously generated metabolites or altered functions of endocrine tissues.
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| 3. |
- Toft, E, et al.
(författare)
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Glutathione transferase isoenzyme patterns in the rat ovary
- 1997
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Ingår i: Chemico-Biological Interactions. - : Elsevier. - 0009-2797 .- 1872-7786. ; 108:1-2, s. 79-93
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Tidskriftsartikel (refereegranskat)abstract
- This study was designed to investigate the expression of different isoenzymes of glutathione transferase (GST) in the rat ovary and to follow possible changes in the pattern of expression during maturation and the different stages of the oestrus cycle. The GST subunits present in the rat ovary (as analyzed by HPLC of affinity-purified GSTs) were A3, A4, M1, M2, M3 and P1. The most abundant subunit in the ovary was A3, but the mu enzymes demonstrated the largest increase (3.5-fold) when the mature ovary was compared to the immature organ. An overall decrease in GST isoenzyme content during dioestrus was observed, but there were no other recurrent changes during the oestrus cycle. Treatment of immature rats with pregnant mare's serum gonadotropin clearly demonstrated that the mu and alpha isoenzymes are up-regulated by gonadotropin stimulation, i.e. a 4-6 fold increase was seen. This treatment also elevated the P1 subunit 3-fold. At present, it is only possible to speculate concerning the mechanism(s) underlying these variations in ovarian GST expression in connection with hormonal changes. The functional significance of these variations is not yet known.
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