OVERSTREET, S.L.*; MAYER, L.M.; DYER, C.A.; PARLOW, A.F.; PROPPER, C.R.: Immunoreactive steroidogenic factor-1 levels in the ovary and pituitary do not change during puberty.

Steroidogenic factor-1 (SF-1) was originally characterized as a transcription factor that regulates tissue specific cytochrome P450 steroid hydroxylase expression. Further investigation of SF-1 lead to the discovery of much a broader role for the protein. SF-1 has been found to be essential to embryonic development along the entire hypothalamic-pituitary-gonad axis, however little has been done to examine the role that SF-1 may play during another critical developmental stage, puberty. SF-1 is a transcription factor involved in the regulation of genes encoding proteins that must be synthesized and available in the pituitary and gonads at the onset of and throughout puberty. SF-1 protein expression was relatively quantitated by Western immunoblot from the pituitary and ovaries of Mus musculus at six developmental stages: 1) day 24 after birth; 2) at vaginal opening; 3) two days post vaginal opening; 4) first estrous; 5) first diestrous; and 6) second estrous to determine changes in SF-1 throughout puberty. SF-1 protein expression was relatively quantitated by Eagle Eye II digital densitometry. No significant differences in SF-1 protein expression were found in either the pituitary or ovaries between the six different developmental stages. These results suggest that changes in SF-1 protein expression are not responsible for the onset of puberty and if SF-1 regulates changes in pituitary and ovarian gene expression during puberty, it may do so by being constitutively present and activated by other cellular processes. It may be that other cofactors, along with SF-1, determine changes in gene expression during puberty in the hypothalamic-pituitary-gonad axis.