Jenny Tong, MD, MPH

Faculty Member, Duke Molecular Physiology Institute

Position

Associate Professor Department of Medicine, Division of Endocrinology, Metabolism, and Nutrition, Duke University Medical Center

Contact

Carmichael Building

919-684-0660

jenny.tong@duke.edu

Summary

Dr. Tong is an Associate Professor in the Division of Endocrinology, Metabolism and Nutrition at Duke University. She completed her clinical endocrinology fellowship and Health Services Research & Development (HSR&D) fellowship training at the University of Washington. She also received formal epidemiology and biostatistics training at the School of Public Health at the University of Washington where she obtained a Masters of Public Health degree.

Dr. Tong has a broad interest in the pathogenesis of type 2 diabetes and obesity and is the PI for several ongoing clinical investigations designed to clarify the role of ghrelin, an orexigenic gut hormone, in the regulation of glucose and energy homeostasis in humans. She is also leading studies to investigate the contribution of tissue-specific ghrelin signaling to the effects of ghrelin on islet cell function, glucose tolerance, and energy intake in rodents. In addition, she uses a translational approach to study the effect of ghrelin on olfaction and sniffing behavior, functions related to food intake. She is experienced in performing studies to measure insulin secretion, insulin sensitivity, food intake, body composition and energy metabolism in rodents and humans. She is also knowledgeable about biostatistics and epidemiology methods. She is currently collaborating with the investigators at the School of Public Health at Harvard and the Pennington Biomedical Research Center to identify psychological, behavioral and biological factors that influence weight loss and weight regain using data collected from the POUNDS LOST trial. Her research has been funded by the NIH/NIDDK since 2007. She has a well-equipped laboratory located at the Duke Molecular Physiology Institute that can perform a wide range of assays to quantify gut hormones, islet hormones and adipokines. The objectives of her current R01 projects are to better understand the role of acyl and desacyl ghrelin in the regulation of glucose metabolism in healthy individuals and those with type 2 diabetes. 

Besides conducting research, Dr. Tong provides clinical care to patients with endocrine disorders and diabetes at the Duke Center for Metabolic and Weight Loss Surgery clinic.

Ghrelin is mainly secreted from the stomach but a small amount is also made in the islet by a novel and distinct cell type. Ghrelin receptor is abundantly expressed in the islets. The effect of ghrelin on beta-cell function in humans was not well defined with contradicting reports in the literature. Moreover, there was little information on the effect of ghrelin on stimulated insulin release prior to our investigation. We performed the first set of proof of concept studies in humans to clarify the effect of ghrelin on glucose-stimulated insulin secretion, insulin sensitivity and glucose tolerance. (1) We also helped define the differential effects of acyl- and desacyl-ghrelin on beta-cell function in healthy individuals.(2,3) Our findings raise the possibility that endogenous ghrelin has a role in physiologic insulin secretion, and that ghrelin antagonism could improve beta-cell function. (4,5)

Many animals rely on olfactory cues to identify sources of nutrition, particularly during fasts when the sense of smell is enhanced. (6) Sniffing is the first stage in olfactory processing and influences olfactory perception. We speculated that manipulating hunger by ghrelin might influence brain circuits controlling sniffing and olfaction, a function of ghrelin that was unknown prior to our investigation. We first identified ghrelin receptors in olfactory circuits in the brain; then observed that ghrelin administration decreased odor detection thresholds and increased sniffing frequency in rats. In humans, ghrelin also enhanced sniff magnitude without affecting pleasantness ratings of odors. This novel role is consistent with ghrelin’s overall function as a signal amplifier at the molecular interface between environmental and nutritional cues and neuroendocrine circuits controlling energy homeostasis. Our publication on the Journal of Neuroscience was accompanied by a press release from the Society for Neuroscience and attracted wide spread media attention. Subsequently my group also contributed to the investigation of the effect of ghrelin on hippocampal inflammation in rodents underwent bariatric surgery and caloric restriction (7) as well as the effect of gastric bypass surgery on sweet cravings in mice (8).

In addition to our pioneering work on the effect of ghrelin on glucose metabolism in humans, we have also been at the forefront of unraveling the effects of ghrelin on several other physiological functions such as growth hormone (isoform) secretion, thermoregulation, and defining its distribution in the lymphatic system. (9,10,11)

Staff

Ramamani Arumugam, PhD

Postdocs / Fellows

Sarah Gray, PhD

Jingjing Niu, PhD

Laura Page, MD