Building Competency in Diabetes Education THE ESSENTIALS

3-6 | CHAPTER 3

brain uses glucose in an insulin-independent way and has a continuous need for glucose as fuel, except in starvation states, but other vital organs (heart, liver, skeletal muscle) can use either glucose or FFAs directly. Insulin is required for the transport and storage process (5,6). Understanding various hormone biosynthesis, secretion and action will facilitate thorough discussion with people living with diabetes about advantages and disadvantages of current therapeutics in diabetes management. Meaningful dialogue about the effects of hormones creates a bridge between science and real-life changes for better diabetes management. Also, this approach can be motivational for successful lifestyle changes regular physical activity and healthy eating. Insulin Pancreatic beta cells regulate the storage and metabolism of fuels through the secretion of insulin (7). The insulin precursor, produced by beta cells, is proinsulin (5). Enzyme-promoted structural changes to proinsulin lead to mature insulin molecules and C-peptide (5). Insulin is a body-building, storing (anabolic) hormone produced in response to higher glucose levels and suppressed with low glucose levels (4,8). C-peptide is stored together and co-secreted with mature insulin (5). Thus, C-peptide is a useful indicator of insulin production and helps distinguish between endogenous and exogenous insulin production when evaluating hypoglycemia (5). Although glucose is the key regulator of insulin secretion, the insulin response is also modulated by insulinotropic hormones, nutrients and neurotransmitters (7). Glucose levels >3.9 mmol/L stimulate insulin synthesis (5). The amount and rate of insulin secretion is also important. Meals cause a biphasic pattern of insulin secretion, with a large burst produced in the first 30 minutes after a meal (first phase) and the remaining over one to two hours (second phase), as illustrated in Figure 1 (9).