Based on the biochemical, immunologic, and structural properties of Glutathione S-transferase superfamily members, the soluble human GSTs are categorized into 4 main classes: alpha, mu, pi, and theta.
The major GST isoenzymes expressed in rat ovaries are subunits A3, A4, M1, M2 and P1 (Hsieh et al., 1997).
Species and sex differences in GST-expression have been described (Butera et al, 1990). Although the human GSTA1 and GSTA2 genes have the same number of exons and introns as their rat and mouse counterparts, the sequences of the 5'-flanking regions of the human alpha-class genes are significantly different from the rodents, suggesting different mechanisms of regulation between human and rodents (Morel et al, 1994).
General function
Metabolism, Enzyme, Transferase, Isomerase
Comment
The glutathione S-transferase (GST) supergene family comprises gene families that encode different isoenzymes. Both cytosolic (particularly the isoenzymes encoded by the alpha, mu and theta gene families) and microsomal GST catalyse the conjugation of reduced glutathione (GSH) with a wide variety of electrophiles which include known carcinogens as well as various compounds that are products of oxidative stress including oxidised DNA and lipid (Hayes et al, 1995).
Cellular localization
Secreted, Cytoplasmic
Comment
Apart from its main cytoplasmic localization, GSTA
GST in porcine was found to have a significant delta 5-3-ketosteroid isomerase activity, which acts in steroid synthesis (Keira et al, 1994).
Glutathione S-transferases (GST) are drug-metabolizing and detoxification enzymes involved in the intracellular transport and metabolism of steroid
hormones. GST alpha was localized to the steroid-producing cells in human ovary (Rahilly et al, 1991).
Gene whose expression is detected by cDNA array hybridization: stress response, cell/cell communication. Also, relative transcript level reproducibly increases during IVM Rozenn Dalbis-Tran and Pascal Mermilloda
Expression regulated by
FSH, LH
Comment
hCG treatment decreased levels of bovine GSTA1 mRNA in preovulatory follicles (Rabahi et al, 1999).
GST activity in the cultured porcine granulosa cells was remarkably increased in the luteinizing process, which was induced by addition of pituitary gonadotropins such as follicle-stimulating hormone (FSH) and luteinizing hormone (LH) to the culture system (Keira et al, 1994).
Ovarian localization
Granulosa, Theca, Luteal cells
Comment
GSTA1 and 2 mRNA was detected in bovine theca interna cells, granulosa cells, corpus luteum but not in oocytes (Rabahi et al, 1999).
In porcine tissues GST was detected within luteinizing and theca interna cells, but not in granulosa cells (Keira et al, 1994).
Strong GSTA immunostaining of theca interna cells is found as well in human ovaries (Rahilly et al, 1991).
Follicle stages
Primordial, Primary, Secondary, Antral, Preovulatory, Corpus luteum
Comment
(Rahilly et al, 1991).) found GSTA expression in human primary follicles.
GSTA was immunolocalized in the granulosa and theca cells of preantral and antral and follicular fluid of large antral bovine follicles (Rabahi et al, 1999).
The expression of different isoenzymes of glutathione transferase (GST), i.e. the cytosolic subunits GSTA1/A2, A3, A4, A5, M1/2, M2 and P1, T2, and the microsomal GST in follicles of different sizes and in corpora lutea from porcine ovary, was investigated by Eliasson et al. (1999).