Department of Molecular and Integrative Physiology
PhD, Mayo Graduate School, 2001
Postdoctoral, University of Florence, 2001-2001
Postdoctoral, Washington University, 2002-2005
My research focus also includes the role of estrogen receptors in glucose regulation. Evidence from both human and rodent studies demonstrates the ability of estrogens to modify glucose homeostasis. Premenopausal women have increased insulin sensitivity compared with age-matched men. Premenopausal women are also less likely to develop insulin resistance and have higher levels of GLUT4, the protein responsible for insulin-stimulated glucose uptake in skeletal muscle. In contrast, following menopause a significant decline in insulin sensitivity occurs along with a corresponding increase in fat mass. Estrogen replacement has been shown to ameliorate the increased risk for type 2 diabetes in postmenopausal women and improve whole body and skeletal muscle glucose metabolism. In animal models, insulin sensitivity and glucose metabolism are impaired following ovariectomy and estrogen replacement protects against insulin resistance. Further, aromatase knockout mice, which lack the ability to synthesize estrogen hormones, are insulin resistant. The primary estrogen receptors, ERα and ERβ, are products of two distinct genes. Increased adiposity occurs in humans and mice as a result of decreased ERα activation and mice with global knockout of ERα exhibit impaired glucose tolerance and skeletal muscle insulin resistance. Based on this evidence, the beneficial effects of estrogens on glucose metabolism are thought to be mediated by ERα. My research aims to 1) discover the signaling pathways mediating the beneficial effects of ERα stimulation on glucose uptake in skeletal muscle and 2) determine the ways in which ERα stimulation alters fatty acid handling in adipose tissue.
Gorres BK, Bomhoff GL, Gupte AA, Geiger PC (2011). Altered estrogen receptor expression in skeletal muscle and adipose tissue of female rats fed a high-fat diet. J Appl Physiol. 110(4):1046-53.
Gorres BK, Bomhoff GL, Morris JK, Geiger PC (2011). In vivo stimulation of ERα increases insulin-stimulated skeletal muscle glucose uptake. J Physiol. 589(Pt 8):2041-54.
Spangenburg EE, Geiger PC, Leinward LA, Lowe DA (2012). Novel Mechanistic Insights Into the Role of Female Sex Steroids in Regulating Physiological and Metabolic Function of Striated Muscle. Invited Reivew, Med Sci Sports Exerc , 44(9):1653-62 .
Paige Geiger, PhD