Associate Professor in Comparative Biosciences
(608) 890-2337

4354C  Veterinary Medicine

Research Interests:Genes that are sexually dimorphic during sex differentiation, focusing on  steroidogenic factor 1 (Sf1) and Iroquois homeobox factor 3 (Irx3).


We are interested in understanding the onset and maintenance of androgen synthesis in developing male gonads. The androgens produced by the developing testis are absolutely essential for development of the male reproductive tract, secondary sex organs, and a masculinized brain. Thus, any factors that disrupt androgen synthesis during this vulnerable stage of development can wreak havoc on the physiology and psychology of affected male individuals. We currently focus on regulation and activity of an essential transcription factor that controls expression of the conversion enzymes within the steroidogenesis pathway, steroidogenic factor 1 (SF1). Approximately midway through gestation in the mouse, SF1 expression is substantially upregulated within the developing testis corresponding to the onset of androgen synthesis. Steroid synthesis within fetal testes occurs within specialized cells called fetal Leydig cells. To understand the biology behind these cells, we take advantage of genetically modified mice to identify important mediators and signaling pathways required for steroidogenesis and SF1 action.

  • Kim B, Kim Y, Rûther U, Jorgensen JS – 2010 The Fused Toes locus is essential for ovarian and contributes to testis development and maturation in mice. In preparation
  • Kim B, Kim Y, Rűther U, Jorgensen JS – 2010 Primordial germ cell colonization and proliferation is impaired in early gonads of Fused Toes mutant mice. In preparation
  • Gao L, Kim B, Kim Y, Lofgren SM, Schultz-Norton JR, Nardulli AM, Heckert LL, Jorgensen JS – 2010 Two regions within the proximal Sf1 promoter work together to drive somatic cell-specific activity in developing gonads of the female mouse. Accepted pending review
  • Jorgensen JS, Stewart AA, Stewart MC, Genovese RL 2010 Ultrasonographic examination of the caudal structures of the distal antebrachium in the horse. Equine Vet Educ 22:146-155
  • Barsoum IB, Bingham NC, Parker KL, Jorgensen JS, Yao HHC 2009 Activation of the hedgehog pathway in the mouse fetal ovary leads to ectopic appearance of fetal Leydig cells and female pseudohermaphroditism. Dev Biol 329(1):96-103