Question

In order to determine the effect of each substance on normal body variables, they were injected intravenously. The results are shown in table below. Assume that enough time was allowed between injections so that the substances do not interfere with one another. Based on the information in table above, which of the following is most likely substance B?

Variable	Baseline values	Values after injecting substance A	Values after injecting substance B	Values after injecting substance C	Values after injecting substance D
Serum ${Ca}^{++}$	2.3mmol/L	2.3mmol/L	2.3mmol/L	3.0mmol/L	2.3mmol/L
Serum ${Na}^{+}$	135mmol/L	135mmol/L	135mmol/L	136mmol/L	135mmol/L
Serum glucose	5.6mmol/L	3.3mmol/L	5.6mmol/L	7.4mmol/L	5.6mmol/L

Based on the information in table above, which of the following is most likely substance A?

• A. Glucagon
• B. Aldosterone
• C. Calcitonin
• D. Parathyroid hormone
• E. Insulin

Answer 1

The correct option is E Insulin

Homeostasis is the process wherein normal body variables are actively regulated inside a defined environment to remain very near to constant. The regulation of concentration of sodium ($N{a}^{+}$) and Calcium ($C{a}^{++}$) ions in the blood as well as glucose levels in blood plasma are examples of Homeostasis.
In the human body, the concentration of blood sugar levels is regulated by the beta cells of the pancreatic islets by secreting insulin into the blood and inhibits the secretion of glucagon into the blood. The table given in the question shows the effect of a substance on the normal body variables after an intravenous injection of the same. According to the given data, the injection of substance A tends to decrease the concentration of Serum glucose below the baseline value. Hence, the substance that was injected is identified as insulin.