Graduation Year

2013

Document Type

Thesis

Degree

M.S.

Degree Granting Department

Biology (Cell Biology, Microbiology, Molecular Biology)

Major Professor

Brant R. Burkhardt

Keywords

FAM3B, Glucose Tolerance, Hepatic Insulin Signaling, Liver, Type 2 Diabetes

Abstract

PANcreatic-DERived Factor (PANDER), or FAM3B, is a 235-amino acid protein strongly expressed within and secreted from the endocrine pancreas. Research surrounding PANDER has revealed a large role for the protein in maintaining glucose homeostasis, as evidenced by several Ad-PANDER overexpressing murine models, our lab's pancreas-specific PANDER transgenic overexpressor, and most recently our mixed genetic C57/129J PANDER knockout (PANKO) mouse. However, PANDER's overall role in glycemic regulation and glucose homeostasis has yet to be studied in a purebred C57BL/6J PANDER knockout model. Here we present the first phenotypic characterization of our global PANDER knockout mouse on a C57BL/6J background (PANKO-C57) where we examined metabolics through glucose/insulin tolerance testing, fasting glycemia, and body weights, the concentrations of hormonal analytes along with lipids and corticosterones, and full elucidation of hepatic insulin signaling through the insulin signaling cascade. Overall, the PANKO-C57 mice exhibited increased body weights with enhanced glucose tolerance and lower fasting glycemia, similar peripheral insulin sensitivities, increased hepatic lipidemia, and enhanced hepatic insulin signaling at critical insulin signaling molecules. Taken together, the PANKO-C57 demonstrates that the disruption of PANDER results in selectively enhanced hepatic insulin signaling yet with increased lipidemia and overall body weight. These findings reveal a novel role for PANDER in differentially controlling lipogenesis and hepatic glucose production that may selectively impact overall glycemic control and potentially facilitate the onset and/or progression of type 2 diabetes.

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