Expression of glutathione transferase isoenzymes in the porcine ovary in relationship to follicular maturation and luteinization

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 th e microsomal GST in follicles of different sizes and in corpora lutea from porcine ovary, was investigated by Western blotting. No immunoreactivity wa s obtained with anti-rat GSTT2 or anti-rat microsomal GST polyclonal antibo dies. In contrast, GSTA1/A2, A3, A4, A5, M1/2, M2 and pi are all expressed in the cytosol from porcine ovaries. In general, the highest levels of thes e GST isoenzymes were present in the cytosol from corpora lutea, in agreeme nt with measurements of activity towards 1-chloro-2,4-dinitrobenzene. Imuno reactivity with anti-rat GSTP1 was only obtained with follicles. The cytoso lic GSTs from follicles and corpora lutea were affinity purified on glutath ione-Sepharose and separated by reversed-phase high-performance liquid chro matography in order to quantitate the different subunits. A peak correspond ing to the class pi subunit was present in follicles. This peak was also se en with corpora lutea, although at very low level. There were four peaks co ntaining class mu subunits. The remaining peaks were concluded to contain t he class alpha subunits, except for two peaks which are suggested to contai n proteins other than GSTs. The levels of the different subunits were quant itated on the basis of the areas under the peaks and the relative amounts i n follicles of different sizes and in corpora lutea corresponded well with the Western blot analysis. (C) 1999 Elsevier Science Ireland Ltd. All right s reserved.