Date of Award


Document Type

Doctoral Dissertation - Open Access

Degree Name

Doctor of Philosophy



First Advisor

Michal L Schwartzman


Recently, a collaboration between Regeneron Pharmaceuticals and the Schwartzman-Garcia labs at New York Medical College published an exome sequencing study of individuals across the United Kingdom, United States, and Mexico which concluded that individuals possessing non-functioning, truncated mutations to the orphan g protein coupled receptor (GPCR), GPR75, had lower BMI and 54% reduced likelihood of obesity. The present study was undertaken to fully characterize the metabolic phenotype of Gpr75 deficient mice when fed a high fat diet (HFD) and explore potential mechanisms by which GPR75 activation links to increased adiposity and decreased glucose tolerance. After 14 weeks of HFD-feeding we observed significant differences in weight gain, with male and female wild-type mice gaining double the amount of weight as the transgenic mice. Surprisingly, mice with Gpr75 deficiency show no differences in caloric intake compared to wild-type animals throughout the feeding period. In contrast, whole-body energy expenditure calculated from volume of oxygen consumption (VO2) and carbon dioxide (VCO2) production decreased in response to HFD-feeding for wild-type animals, while remaining unchanged compared to baseline for transgenic animals. This correlated with increased expression of mitochondrial uncoupling proteins (UCPs) in different adipose tissue depots, whose role in diet-induced obesity prevention is well documented.