Fredrick Stormshak

Distinguished Emeritus Professor, Biochemistry and Biophysics

Office: Withycombe 216
Phone: (541) 737-2325
Departmental Web Page
Pub Med

Ph.D. 1965, University of Wisconsin, Madison

KEYWORDS: Hormone Action; Steroid Receptors; Oxytocin; Protein Kinase C; Calpains

The major focus of research conducted in our laboratory is the elucidation of the mechanism of action of steroids and prostaglandin F2a in regulating uterine and ovarian function during various physiological states.
The corpus luteum is being extensively investigated to elucidate the factors that regulate the development and function of this ovarian endocrine gland. Corpora lutea of a number of mammalian species have been found to synthesize and secrete oxytocin during the estrual or menstrual cycle. We have shown that prostaglandin F2a (PGF2a) stimulates oxytocin secretion by the bovine corpus luteum in vivo and in vitro. The action of PGF2a in provoking the secretion of oxytocin is mediated by activation of protein kinase C (PKC) isozyme(s), which specifically phosphorylate a Myristoylated Alanine Rich C Kinase Substrate (MARCKS) protein that cross-links actin filaments in the cytoskeletal cortex underlying the plasma membrane. Phosphorylation of this protein is positively correlated with PGF2a-induced exocytosis of oxytocin. Research is being conducted to further define the actions of PGF2a and the MARCKS protein in regulating exocytosis of oxytocin from the luteal cell.
Research is also currently being conducted to examine the nongenomic effects of progesterone in regulating the binding of oxytocin to its receptor in the uterine endometrium. The acquired data suggest that this steroid hormone is acting at the level of the plasma membrane as well as in the nucleus to alter response of the target cell to oxytocin.