STEROIDOGENIC FACTOR-1 MESSENGER-RIBONUCLEIC-ACID EXPRESSION IN STEROIDOGENIC AND NONSTEROIDOGENIC HUMAN TISSUES - NORTHERN BLOT AND IN-SITU HYBRIDIZATION STUDIES

Steroidogenic factor-1 (SF-1), a tissue-specific orphan nuclear recept or, regulates the genes of several steroidogenic enzymes, Mullerian in hibiting substance, and the gonadotrophins. Also, this transcription f actor is crucial for hypothalamic, adrenal, and gonadal organogenesis in the mouse. We recently cloned the human SF-1 (hSF-1) complementary DNA (cDNA) and now report the distribution of this factor's messenger RNA (mRNA) in human tissues. Northern blot analyses of peripheral tiss ues revealed high hSF-1 mRNA expression in the adrenal cortex and the gonads, but no hSF-1 mRNA was detected in the placenta. High hSF-1 mRN A expression also was seen in the spleen. In this tissue, in addition to the main transcript of 3.5-4 kb seen in the adrenal and gonads, two additional transcripts of 4.4 kb and 8 kb were noted. The additional 4.4-kb transcript also was seen in several peripheral tissues and vari ous components of the brain. However, adult liver and heart showed onl y the 4.4-kb transcript. In the human brain, hSF-1 mRNA expression was widespread, including several components of the limbic system. In sit u hybridization studies confirmed the strong expression of hSF-1 mRNA in adrenal cortex, ovary, testis, and the spleen, primarily within ret iculoendothelial cells. Thus, in the human, the hSF1 mRNA is present i n both steroidogenic and nonsteroidogenic tissues, albeit not in the p lacenta. In the central nervous system, the expression of hSF-1 mRNA i s widespread. It is composed of several different mRNA species distrib uted in a tissue-specific fashion. These findings suggest that hSF-1 m ay play a role in reticuloendothelial/immune cell maturation and/or fu nction, as well as nervous system development and/or neurosteroid bios ynthesis.