Question

A hormone that acts upon the renal tubule and blood capillaries is:
A) Glucagon
B) Aldosterone
C) Vasopressin
D) Glucocorticoids

Answer 1

Hint: This hormone is secreted by posterior pituitary or neurohypophysis. Although the posterior pituitary does not synthesise hormones, it does store and release two hormones. These hormones are synthesised by the hypothalamus and are transported axonally to the neurohypophysis. This hormone is also called pitressin.

Complete step-by-step answer:
Vasopressin is also called pitressin. It increases the reabsorption of water by the distal convoluted tubule and collecting duct of the nephron and thereby reduces the loss of water through urine (dieresis). Hence, it is also called an antidiuretic hormone or ADH. The urine becomes more concentrated as water is reabsorbed. In the absence of ADH, urine output increases more than ten folds. Drinking alcohol causes frequent urination because alcohol inhibits the secretion of ADH. ADH causes vasoconstriction, thereby, increasing blood pressure. So vasopressin is the hormone that acts on blood capillaries and renal tubules.
Aldosterone is the major mineralocorticoid . It regulates the homeostasis of two mineral ions, namely sodium and potassium ions. It also helps in the maintenance of electrolytes, body fluid, osmotic pressure, and blood pressure. Glucocorticoids are involved in carbohydrate metabolism. These include cortisol(hydrocortisone), corticosterone, and cortisone. The principal glucocorticoid is cortisol. The secretion of glucocorticoids is stimulated by ACTH from the anterior pituitary. Glucagon stimulates glycogenolysis resulting in an increased level of glucose in the blood( hyperglycemia). It also stimulates the process of gluconeogenesis.
Hence the correct answer is option C.

Note: The renin-angiotensin-aldosterone system controls the secretion of aldosterone. It acts primarily on the kidney to promote the absorption of sodium and excretion of potassium. Increased sodium level contributes to the retention of water and thus increased blood volume.