|Sandra L. Petersen
Professor of Biology, University of Massachusetts
Associate Dean of the Graduate School
Director of the Northeast Alliance for Graduate Education and the Professoriate
Ph.D.: Oregon State University
Molecular and Cellular Mechanisms Underlying the Neural Control of Ovulation
The work in my laboratory focuses on the molecular and cellular mechanisms by which the ovary and brain communicate to ensure that the brain signal for ovulation is sent when ovarian follicles are fully mature. As follicles approach maturity, they release increasing amounts of estrogen and progesterone into the blood. The rise in circulating levels of these ovarian steroids signal specific neurons in the brain to increase release of the peptide, luteinizing hormone-releasing hormone (LHRH). This increased secretion of LHRH then triggers a surge release of luteinizing hormone (LH) from the pituitary gland, which, in turn, stimulates ovulation.
The goal of one project in the laboratory is to determine the transsynaptic signal transduction mechanisms by which estrogen and progesterone trigger changes in LHRH gene expression, translation, and release. Considering that LHRH neurons do not have classical estrogen or progesterone nuclear receptors, we are working to determine what neurotransmitter systems and signal transduction pathways convey information about steroid levels to LHRH neurons.
The goal of the second project in my laboratory is to determine how environmental pollutants that activate the arylhydrocarbon receptor (AhR) interfere with ovulation in mammals. The AhR is a basic/helix-loop-helix protein that acts as a ligand-activated transcription factor and mediates the toxic effects of halogenated aromatic hydrocarbons present as ubiquitous environmental contaminants. These contaminants are extremely stable and present in the body fat of animals, including humans, throughout the world. We are currently working to determine the mechanisms by which activation of the AhR interferes with estrogen action in cells of the brain and/or pituitary gland.
OTTEM, N.E. AND S.L. PETERSEN (2004). Dual-phenotype GABA/glutamate neurons in adult preoptic area: Sexual dimorphism and function. Journal of Neuroscience 24(37):8097-8105
HRABOVSZKY, E., I. KALLO, A. STEINHAUSER, I. MERCHENTHALER, C.W. COEN, S.L. PETERSEN, Z. LIPOSITS (2004). Estrogen receptor-beta in oxytocin and vasopressin neurons of the rat and human hypothalamus: Immunocytochemical and in situ hybridization studies. J Comp Neurol. 473(3):315-33
PETERSEN, S.L., E.N. OTTEM AND C.D. CARPENTER (2003). Direct and indirect regulation of GnRH neurons by ovarian steroids. Biology of Reproduction 69:1771-1778
FLORES, C.A., P. SHUGHRUE, M. LANE, S.L. PETERSEN AND S.S. MOKHA (2003). Sex-related differences in the distribution of OR receptor mRNA and colocalization with estrogen receptor mRNA in neurons of the spinal trigenimnal nucleus caudalis in the rat. Neuroscience 118:769-778.
CURRAN-RAUHUT, M. A. AND S.L. PETERSEN (2003). Oestradiol-induced temporal changes in tyrosine hydroxylase mRNA levels are not limited to subpopulation of A1 and A2 noradrenergic neurons with a high incidence of colocalization with oestrogen receptor-alpha or -beta mRNA. J Neuroendocrinol. 15(3):296-303.
Hays, L.E., C.D. Carpenter and S.L. Petersen (2002). Evidence that GABAergic Neurons in the preoptic area of the rat brain are targets of 2,3,7,8-tetrachlorodibenzo-p-dioxin during development. Environ Health Perspect 110 (Suppl 3):369-376
Curran-Rauht, M.A. AND S.L. Petersen. (2002) Regulation of glutamic acid decarboxylase 65 and 67 gene expression by ovarian steroids: Identification of two functionally distinct populations of GABA neurons in the preoptic area. J. Neuroendocrinology 14(4):310-7
Flores, C.A., P. Shughrue, M. Lane, S.L. Petersen and S.S. Mokha (In Press). Sex-related differences in the distribution of ORL2 receptor mRNA and colocalization with estrogen receptor mRNA in neurons of the spinal trigenimnal nucleus caudalis in the rat. J. Neuroscience.
Hrabovszky, E and S.L. Petersen (In Press) Increased concentrations of radioisotopically-labeled complementary ribonucleic acid (cRNA) probe, dextran sulfate and dithiothreitol in the hybridization buffer can improve results of in situ hybridization histochemistry. J Histochem. Cytochem.
Curran-Rauht, M.A. and S.L. Petersen. (2002) Regulation of glutamic acid decarboxylase 65 and 67 gene expression by ovarian steroids: Identification of two functionally distinct populations of GABA neurons in the preoptic area. J. Neuroendocrinology 14(4):310-7