Boston Area Metabolic Physiology Core

Overview

The Boston Area Metabolic Physiology Core provides consulting and teaching, use of DEXA scanner for determination of body fat and/or bone density, and use of Coulter Counter to measure cell number and cell size distribution.

Services

Consultation and assistance on writing animal protocols regarding services offered by the Core

In vivo studies

• Glucose homeostasis: glucose tolerance tests, insulin tolerance tests
• Lipid homeostasis: lipid tolerance test, hepatic VLDL production
• In vivo lipogenesis in adipose tissues and liver (Terminal study)
• Body composition: DEXA analysis of body fat or bone density, carcass hydrolysis (terminal study)
• Animal models of insulin resistance (dietary, genetic)
• Signaling studies in response to injections of insulin, and leptin (Terminal study)- Experimental design and consultation
• Measurment of hormone and metabolite concentrations – timing, stimulation, feeding status
• Euglycemic-hyperinsulinemic clamp studies- Experimental design and consultation only
• Measurement of food intake in response to administration of orexigenic and anorexigenic agents

In vitro studies

• Isolation of adipocytes – counting the number and cell size distribution of adipocytes using our new coulter counter equipped with a multisizer (number and size of cells are determined on the same sample at the same time)
• Glucose transport and metabolism studies in isolated adipocytes. Insulin dose response (glucose transport, glucose utilization, lipolysis)
• Insulin or leptin signaling in isolated adipocytes – dose response
• Glucose transport in EDL and Soleus muscle. Insulin dose response
• Insulin signaling in EDL and Soleus muscle– dose response
• Preparation and culture of primary rat and mouse pancreatic islets – Consultation, hands on training and protocols to obtain pancreatic islets, culture them and measure glucose-stimulated insulin release. The latter can also be used to assess quality of islet preparation
• Preparation and culture of primary mouse hepatocytes – Consultation, hands on training and protocols to obtain primary hepatocytes, culture them and measure glucose production in response to glucagon and insulin. The latter can also be used to assess quality of hepatocyte preparation

Biochemical assays

• Measurement of hormones and metabolites in plasma/serum of mice, rat or human subjects (Elisa, RIA, WB). Hormones: Insulin, leptin, adiponectin, resistin, RBP4, TTR. Metabolites: Glucose, free fatty acids, triglycerides, cholesterol
• Insulin signaling: PI-3 kinase, Akt, GSK3, p70s6 kinase, MAP kinase, glycogen synthase activation; phosphorylation of insulin receptor and IRSs
• Leptin signaling: phosphorylatiom of Jaks, stats, AMP kinase, MAP kinase, acetyl-coA carboxylase, p70S6 kinase phosphorylation
• Enzyme activity assays: AMP Kinase immune complex assay, Glucose 6-Phosphatase
• Tissue glycogen or lipid content.

Dissections and surgeries (teaching and consultations only):

• Dissection of adipose tissues, brown adipose tissues, liver, kidney, heart, pectoralis muscle and leg muscle (tibialis anterior, gastrocnemius, EDL and Soleus)
• Placement of intravenous (jugular) catheter for direct delivery of hormones and compounds directly in blood stream
• Subcutaneous implantation of osmotic minipumps
• Subcutaneous white adipose tissue biopsy
• Subcutaneous white adipose tissue transplantation
• Formalin perfusion for in situ tissue fixation

Equipment

• DEXA scanner for non-invasive determination of body composition and bone mineral density
• Coulter Counter equipped with a multisizer to measure adipocyte number and size distribution on the same sample at the same time
• Stereotaxic table for other investigators to use to implant a brain cannula for direct delivery of a compound into the brain
• CODA 8 for non invasive measurement of blood pressure of mice
• “wheel cage system” for recording of spontaneous exercise of mice
• Telemetry system for measurement of mouse core body temperature
• Thermalert TH-5 thermometerfor measurement of core body temperature (rectal probe)
• CMA 401 Infusion pumps (from Harvard Apparatus) for continuous delivery of compounds