Question

1. Briefly describe three ways that insulin is stimulated? A direct response to high glucose is not an acceptable answer.

2. What is the clinical relevance of detecting glucose in the urine?

Answer 1

The three ways in which insulin production is stimulated are

1.The glucose content of the blood. As the blood glucose increases the GLUT-2 transporter in beta cells of Pancreas transport glucose to the inside of the cell. This glucose undergoes glycolysis and Krebs cycle which leads to an increase in ATP production. This increase in cellular ATP closes voltage-gated potassium channels, leading to depolarisation of beta cells. This causes the release of calcium ions, which in turn leads to the release of preformed insulin.

2. The fatty acids can enhance insulin secretion even at low concentrations of glucose. This leads to the uptake of free fatty acids by peripheral tissues.

3. Hormones like growth hormone, cortisol, PRL, and gonadal steroids can induce insulin secretion. Insulin is overall an anabolic hormone. Combining the anabolic effect with the Growth hormone, insulin promotes growth and development.

The presence of glucose in the urine is an important sign of diabetes mellitus. When glucose concentration is higher than the Renal threshold glucose gets excreted through urine.