Request for Funding

Medical Student Research Fellowship for Summer 2001

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: Transcription-Independent Signaling by Steroids

Human subjects IRB approved project number (where applicable):

Animal subjects IRB approved project number (where applicable):

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:

A longstanding unanswered question in steroid physiology is how steroid hormones interact with membranes to mediate "nongenomic", or transcription-independent, effects. The growing list of rapid, steroid-triggered, nongenomic signaling events includes estrogen-mediated upregulation of nitric oxide synthase in endothelial cells, vitamin D-induced increases in intracellular calcium in osteosarcoma cells, and progesterone-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 progesterone-induced maturation, or re-entry into meiosis, of frog oocytes as a system to study transcription-independent signaling by steroids. Progesterone-mediated oocyte maturation is reproducible, biologically relevant, and easily measured. In addition, oocytes can be manipulated with relative ease in vitro to study steroid-mediated signaling. We are interested in both identifying novel steroid receptors located at the cell membrane and further characterizing the signaling events triggered by steroids binding to these molecules. Specifically, we have focused on the role of G proteins and G protein-coupled receptors in mediating progesterone-induced signaling events. We hope that our studies will not only give us information about progesterone-induced processes in oocytes, but will also lead to a better understanding of the many other fascinating nongenomic effects of steroids.

Previous Research Activities or Publications with Medical Students:

Nongenomic Activation of Progesterone Receptors in Xenopus Oocytes

Kristin Bruce, 2001 Annual Medical Student Research Forum

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