Professor, Physiology & Pharmacology, Oregon Health & Science University, USA
Senior Scientist, Division of Neuroscience, Oregon National Primate Research Center, USA
Dr Rønnekleiv received her Ph.D. in Physiology from UT Southwestern Medical School (1974). After one year of postdoctoral training at UCLA she did a three-year Alexander von Humboldt-funded fellowship at the Max Planck Institute for Biophysical Chemistry in Gøttingen, Germany.
The Rønnekleiv lab is investigating the function and regulation of gonadotrophin releasing hormone (GnRH) neurons. The GnRH neurons control reproduction and are therefore critical for the survival of the species. These neurons migrate from the nose during development to their species-specific location in the hypothalamus (Rønnekleiv and Resko, Endocrinology, 1990). For our studies we are combining whole-cell patch recording with single cell (sc) harvesting and scRT-PCR to explore membrane properties, intracellular signaling cascades and gene expression in individual neurons. We have shown that the mRNA expression and function of ion channels, important for burst firing in GnRH neurons, are regulated by 17ß-estradiol (E2). Our current work focuses on the mechanism by which the upstream peptide, kisspeptin, induces burst firing and GnRH release. To date, kisspeptin neurons provide the most potent excitatory drive to GnRH neurons, and it is known that patients with deletion in its cognate receptors GPR 54 (Kiss1 receptor) exhibit hypothalamic hypogonadism.
The lab is also studying the role of E2 and STX (the selective ligand for a putative membrane estrogen receptor) in modulating hypothalamic control of temperature and energy homeostasis in a number of animal models including guinea pig and rhesus monkey. Current studies in collaboration with Dr. Martin Kelly are focused on E2 and STX regulation of proopiomelanocortin (POMC) and neuropeptide Y (NPY) neurons that have opposing roles in the control of feeding and metabolism. In addition, they have recently embarked on studies of arcuate kisspeptin neurons and the interaction between E2, leptin and insulin acting through multiple signaling cascades to affect kisspeptin neuronal excitability and ultimately the reproductive cycle. We have active collaborations with a number of investigators at the Oregon National Primate Research Center including Drs. Sergio Ojeda, Cynthia Bethea, Henryk Urbanski, Martha Neuringer, Steven Kohama and Susan Smith.