POSSIBLE INVOLVEMENT OF TRANSFORMING GROWTH-FACTOR-BETA-1 AND TRANSFORMING-GROWTH-FACTOR-BETA RECEPTOR-TYPE-II DURING LUTEINIZATION IN THE MARMOSET OVARY

The expression of transforming growth factor-beta 1 (TGF-beta 1), and transforming growth factor-beta receptor type II (T beta R-II), were e valuated in periovulatory marmoset ovaries. Histochemical methods were used, in particular double-labelling techniques, in order to correlat e growth factor/receptor expression with proliferation (Ki 67), apopto sis (TUNEL method) and luteinization (3 beta-hydroxysteroid dehydrogen ase (3 beta-HSD)). The latter was used as a luteinization marker. Peri ovulatory ovaries are especially suited for studying all aspects since they typically consist of small non-luteinized follicles, large lutei nizing follicles and corpora lutea accessoria (Clas), which have devel oped from large luteinizing follicles, TGF-beta 1 and T beta R-II expr ession was found in luteinizing theca cells of large periovulatory fol licles and in all luteal cells of Clas, Non-luteinized theca cells, in cluding those of small follicles were always devoid of any immunostain ing. Granulosa cells of small follicles were immunopositive for T beta R-II. Large follicles with granulosa cell immunoreactivity of both an tibodies coexisted with non-reactive follicles of comparable size. The highest activity of the luteal marker enzyme 3 beta-HSD was co-locali zed in the same cells that expressed TGF-beta I and T beta R-II, The d ouble-labelling experiments revealed that TGF-beta 1 and T beta R-II e xpression is not correlated with proliferation or apoptosis of follicu lar cells. Our results indicate that TGF-beta 1 and T beta R-II partic ipate in differentiation processes, i.e. luteinization, rather than pr oliferation. In particular, the dynamics of T beta R-II expression app ear highly related to the process of luteinization.