Insulin is released from pancreatic b cells when blood glucose levels increase and glucagon is released from pancreatic a cells when blood glucose levels decrease. Blood glucose concentration is tightly controlled and at the basic level it appears that glucose binds to GLUT2 receptors on b cells increasing the concentration of ATP because of the increased concentration of glucose in these cells. The increase in ATP decreases potassium concentrations and calcium channels are opened leading to insulin secretion. There are, however, a number of other insulin/glucagon regulators such as amino acids,catecholamines, insulin, neurotransmitters and free fatty acids. Consequently the search for causes of obesity requires careful focus and much of current research focuses on G Protein Coupled Receptors.Which of the following is not of special interest to those studying GPCR and their involvement in diabetes and obesity?

a. allelic (SNP) differences in the extracellular domain of GPCRs between obese and controls

b. classes of GPCRs found in target tissues thought to be associated with obesity

c. a subunits associated with G proteins in tissues thought to be associated with obesity

d. the role of uncoupling mitochondrial membrane proteins in target tissues

e. the binding of molecules other than glucose to GPCRs on target tissues