Request for Funding

Medical Student Research Fellowship for Summer 2002

Mentor: Stephen R Hammes
Department: Internal Medicine
Room number: Y9.310
Mail Code: 8857
Phone number: 214-648-4793
E-mail: stephen.hammes@utsouthwestern.edu
Project title: Steroid Signaling in the Ovary

Human subjects IRB approved project number (where applicable):

Animal subjects IRB approved project number (where applicable): 0867-01-01-1

Project Type (patient-based research, animal-based research, or basic research; this characterization is only to permit a general classification for grouping similar types of projects) Basic Research

Brief Description of Project:
Our lab is interested in how steroid hormones interact with membranes to mediate transcription-independent, or nongenomic, effects. The growing list of rapid, steroid-triggered, nongenomic signaling events includes estrogen-mediated upregulation of nitric oxide synthase (NOS) in endothelial cells, vitamin D-induced increases in intracellular calcium in osteosarcoma cells, and steroid-induced maturation of frog and fish oocytes. These steroid-induced signaling events may mediate important biological processes such as blood vessel relaxation, bone metabolism, and fertilization.
Our laboratory uses the phenomenon of androgen-induced maturation of frog oocytes as a system to study transcription-independent steroid signaling. Our interest in this system is three-fold: First, in contrast to the other processes described above, androgen-induced oocyte maturation is reproducible, biologically relevant, and easily measured. Second, oocytes can be manipulated with relative ease in vitro to study androgen-mediated events. Finally, while physiologic levels of androgens may be important for normal oocyte development, supraphysiologic concentrations may be promoting ovarian pathology, as seen in polycystic ovarian disease (PCOS).
We are interested in both identifying novel steroid receptors located at the cell membrane and characterizing the role of classical steroid receptors in the maturation response. In addition, we would like to further characterize the signaling events triggered by steroids binding to these molecules, and have focused on the role of G proteins in mediating nongenomic steroid-induced signaling.
We hope that our studies will lead to a better understanding of how steroids can signal independent of transcription. Further, we hope that our work will further elucidate the critical role of androgens in ovarian development and pathology.

Previous Research Activities or Publications with Medical Students:

Bruce, Kristin and Hammes, S.R., Nongenomic Actions of Progesterone in Xenopus Oocytes, Poster presented at the 39th Medical Student Research Forum.

Stair, Matthew and Hammes, S.R., Differential Sensitivities of the Xenopus Androgen Receptor and the Human Androgen Receptor, Oral Presentation at the 40th Medical Student Research Forum.

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