THE EXPRESSION OF SF-1 AD4BP IS RELATED TO THE PROCESS OF LUTEINIZATION IN THE MARMOSET (CALLITHRIX-JACCHUS) OVARY/

Expression of the nuclear receptor, steroidogenic factor-1 (SF-1/Ad4BP ), was studied in a primate (marmoset) ovary using immunohistochemical , RT-PCR, and immunoblot techniques. The periovulatory phase was compa red with the luteal phase. With PCR we found a marmoset homolog of SF- 1/Ad4BP to be expressed in ovarian and other steroidogenic tissues. Ch aracteristically, the periovulatory ovaries consisted of growing (non- luteinized) small follicles together with large luteinizing follicles and many corpora lutea accessoria (Clas), which had developed from atr etic large follicles. During the luteal phase, true corpora lutea (Cls ) were additionally found. In general, we found that small follicles w ere devoid of any immunoreactivity of SF-1/Ad4BP. In large follicles, the luteinizing theca and granulosa cells express SF-1/Ad4BP. All lute al cells of Clas showed a nuclear staining in both ovary types. In Cls , only a few luteal cells were positive. Large follicles of different sizes showed no differences in expression level, as evidenced by immun oblot analysis. Our results indicate that SF-1/Ad4BP participates in t he activation of gene transcription during the onset of luteinization and that Clas are essential for ovarian luteal function.