The hypothalamic–hypophyseal–gonadal regulation of hepatic glutathione S-transferases in the rat
26
Citation
20
Reference
10
Related Paper
Citation Trend
Abstract:
Hepatic glutathione S-transferase activities were determined with the substrates 1,2-dichloro-4-nitrobenzene and 1-chloro-2,4-dinitrobenzene. Sexual differentiation of glutathione S-transferase activities is not evident during the prepubertal period, but glutathione conjugation with 1,2-dichloro-4-nitrobenzene is 2–3-fold greater in adult males than in females. Glutathione conjugation with 1-chloro-2,4-dinitrobenzene is slightly higher in adult males than adult females. No change in activity was observed after postpubertal gonadectomy of males or females. Neonatal castration of males results in a significant decrease in glutathione conjugation with 1,2-dichloro-4-nitrobenzene. Hypophysectomy, or hypophysectomy followed by gonadectomy did result in significantly higher glutathione S-transferase activities in both sexes. These increases can be reversed by implanting an adult male or female pituitary or four prepubertal pituitaries under the kidney capsule. Postpubertal sexual differentiation of glutathione S-transferase activities is neither dependent on pituitary sexual differentiation nor pituitary maturation. Prolactin concentrations are inversely related to glutathione S-transferase activities in hypophysectomized rats with or without ectopic pituitaries. Somatotropin exogenously administered to hypophysectomized rats results in decreased glutathione S-transferase activities, whereas prolactin has no effect. Adult male rats treated neonatally with monosodium l-glutamate to induce arcuate nucleus lesions of the hypothalamus have decreased glutathione S-transferase activities towards 1,2-dichloro-4-nitrobenzene and decreased somatotropin concentrations. Our experiments suggests that sexual differentiation of hepatic glutathione S-transferase is a result of a hypothalamic inhibiting factor in the male (absent in the female). This postpubertally expressed inhibiting factor acts on the pituitary to prevent secretion of a pituitary inhibiting factor (autonomously secreted by the female), resulting in higher glutathione S-transferase activities in the adult male than the adult female.Keywords:
Hypophysectomy
Glutathione S-transferase
Sexual Differentiation
Transferase
Glutathione S-transferase
Transferase
Cite
Citations (119)
A glutathione transferase from human mononuclear leucocytes with high activity towards trans-stilbene oxide (GT-tSBO) was purified. GT-tSBO is expressed in only about 50% of the individuals studied. As judged from activity measurements, immunological studies and the fact that only those individuals who express glutathione transferase mu have high activity towards trans-stilbene oxide, it is concluded that the hepatic transferase mu is identical with the glutathione transferase (GT-tSBO) in mononuclear leucocytes.
Transferase
Glutathione S-transferase
Glutathione transferase
Cite
Citations (73)
Glutathione S-transferase
Transferase
clone (Java method)
Glutathione transferase
Cite
Citations (32)
The glutathione S-transferases are a group of proteins with overlapping substrate specificities and ligand-binding capacities. This report examines certain approaches to the measurement of transferase B (ligandin) in the rat liver. The ratio of catalytic activities toward 1-chloro-2,4-dinitrobenzene and 1,2-dichloro-4-nitrobenzene gives some indication of the relative proportions of the various transferases present in 100 000 g supernatants. The fraction of catalytic activity towards 1-chloro-2,4-dinitrobenzene, due to transferase B, was best measured by immunoprecipitation with anti-(transferase B). Male rat liver exhibited three times more activity towards 1,2-dichloro-4-nitrobenzene than female tissue; however, the activities towards 1-chloro-2,4-dinitrobenzene were almost identical. By assuming a specific activity of 11 mumol/min per mg, immunoprecipitable transferase B comprised 4.5 +/- 0.2% of total protein in the 100 000 g supernatant of female rat liver, and 70% of the transferase activity towards 1-chloro-2,4-dinitrobenzene. The amount of transferase B in the 100 000 g supernatant from male rat liver is significantly lower with respect to both fraction of total protein (3.3 +/- 0.2%) and overall transferase activity towards 1-chloro-2,4-dinitrobenzene (48%). Hypophysectomy eliminated this sex difference in the hepatic concentration of glutathione S-transferase B.
Transferase
Glutathione S-transferase
Hypophysectomy
Immunoprecipitation
Specific activity
Glutathione transferase
Cite
Citations (52)
GSSG selectively elutes two GSH transferases from a mixture of rat GSH transferases bound to a GSH-agarose affinity matrix. One is a form of GSH transferase 1-1 and the other is shown to be GSH transferase 8-8. By using tissues that lack this form of GSH transferase 1-1 (e.g. lung), GSH transferase 8-8 may thus be purified from cytosol in a single step. Quantitative analysis of the tissue distribution of GSH transferase 8-8 was obtained by h.p.l.c.
Transferase
Glutathione S-transferase
Glutathione transferase
Cite
Citations (53)
A set of inhibitors that are useful for distinction of three types of human cytosolic glutathione transferase is presented. The near‐neutral transferase is inhibited most effectively by Cibacron blue (itI 50 = 0.05 μM), the acidic transferase by Cibacron blue (itI 50 = 0.5 μM), and the basic transferase by tributyltin acetate (itI 50 = 0.1 μM). The use of any of these two compounds makes possible differentiation between all three types of human transferase.
Transferase
Glutathione S-transferase
Glutathione transferase
Cite
Citations (88)
Six forms of glutathione transferase with pI values of 4.6, 5.9, 6.8, 7.1, 8.5 and 9.9 have been isolated from the cytosol fraction of normal skin from three human subjects. The three most abundant enzymes were an acidic Class Pi transferase (pI 4.6; apparent subunit Mr 23,000), a basic Class Alpha transferase (pI 8.5; apparent subunit Mr 24,000) and an even more basic glutathione transferase of Class Alpha (pI 9.9; apparent subunit Mr 26,500). The last enzyme, which was previously unknown, accounts for 10-20% of the glutathione transferase in human skin. The novel transferase showed greater similarities with rat glutathione transferase 2-2, another Class Alpha enzyme, than with any other known transferase irrespective of species. The most striking similarities included reactions with antibodies, amino acid compositions and identical N-terminal amino acid sequences (16 residues). The close relationship between the human most basic and the rat glutathione transferase 2-2 supports the classification of the transferases previously proposed and indicates that the similarities between enzymes isolated from different species are more extensive than had been assumed previously.
Glutathione S-transferase
Transferase
Glutathione transferase
Cite
Citations (76)
The purification of a hybrid glutathione S-transferase (B1 B2) from human liver is described. This enzyme has an isoelectric point of 8.75 and the B1 and B2 subunits are distinguishable immunologically and are ionically distinct. Hybridization experiments demonstrated that B1 B1 and B2 B2 could be resolved by CM-cellulose chromatography and have pI values of 8.9 and 8.4 respectively. Transferase B1 B2, and the two homodimers from which it is formed, are electrophoretically and immunochemically distinct from the neutral enzyme (transferase mu) and two acidic enzymes (transferases rho and lambda). Sodium dodecyl sulphate/polyacrylamide-gel electrophoresis demonstrated that B1 and B2 both have an Mr of 26 000, whereas, in contrast, transferase mu comprises subunits of Mr 27 000 and transferases rho and lambda both comprise subunits of Mr 24 500. Antisera raised against B1 or B2 monomers did not cross-react with the neutral or acidic glutathione S-transferases. The identity of transferase B1 B2 with glutathione S-transferase delta prepared by the method of Kamisaka, Habig, Ketley, Arias & Jakoby [(1975) Eur. J. Biochem. 60, 153-161] has been demonstrated, as well as its relationship to other previously described transferases.
Transferase
Glutathione S-transferase
Glutathione transferase
Cite
Citations (88)
Transferase
Glutathione S-transferase
Phenobarbital
Specific activity
Glutathione transferase
Cite
Citations (10)
Glutathione S-transferase
Transferase
Crystallin
Cite
Citations (31)