Fredrick Stormshak
Distinguished Professor Emeritus
541-737-2325
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Education
Ph.D. 1965, University of Wisconsin
Research
Research is currently being conducted to elucidate the mechanism of action of prostaglandin F2a in regulating the exocytosis of oxytocin from the corpus luteum. Prostaglandin F2a has been found to activate at least two isozymes of PKC in the bovine corpus luteum. We have found that activation of PKC causes phosphorylation of a myristoylated alanine rich C kinase substrate (MARCKS) protein. The MARCKS protein is one of many peripheral proteins associated with the plasma membrane that crosslink the actin filaments forming the cortex of the luteal cell cytoskeleton. Our research has shown that prostaglandin F2a-induced phosphorylation of MARCKS results in its translocation to the cytoplasm; a phenomenon that is closely correlated with the exocytosis of oxytocin from the luteal cell. Using a phosphorylation mutant GFP-MARCKS construct we have demonstrated that phosphorylation of MARCKS is essential for downstream signal transduction that promotes the transport or movement of vesicles containing oxytocin to the plasma membrane.
In a closely related area of study, research is being conducted to examine the nongenomic effect of progesterone in suppressing the binding of oxytocin to its receptor in the ovine uterine edometrium. Results of our research suggest that progesterone binds to a high affinity receptor site in the plasma membrane preventing the binding of oxytocin to its receptor. Future research will focus on determining whether this nongenomic inhibitory action of progesterone is a consequence of the ability of the steroid to interfere with oxytocin receptor dimerization.
In collaboration with scientists at the Oregon Health and Science University we are investigating the neuroendocrine basis for male-oriented behavior in male sheep (rams). These individuals have been found to exhibit reduced aromatase activity in the preoptic area of the hypothalamus and a hypothalamic sexually dimorphic nucleus (SDN) comparable to that found in female sheep. Future research will focus on the in utero factors that contribute to these hypothalamic morphological and biochemical characteristics during sexual development of the brain of the fetus.
In a closely related area of study, research is being conducted to examine the nongenomic effect of progesterone in suppressing the binding of oxytocin to its receptor in the ovine uterine edometrium. Results of our research suggest that progesterone binds to a high affinity receptor site in the plasma membrane preventing the binding of oxytocin to its receptor. Future research will focus on determining whether this nongenomic inhibitory action of progesterone is a consequence of the ability of the steroid to interfere with oxytocin receptor dimerization.
In collaboration with scientists at the Oregon Health and Science University we are investigating the neuroendocrine basis for male-oriented behavior in male sheep (rams). These individuals have been found to exhibit reduced aromatase activity in the preoptic area of the hypothalamus and a hypothalamic sexually dimorphic nucleus (SDN) comparable to that found in female sheep. Future research will focus on the in utero factors that contribute to these hypothalamic morphological and biochemical characteristics during sexual development of the brain of the fetus.