Which of the following statements are true/false?

I. Calcitonin regulates the metabolism of calcium.

II. Oxytocin stimulates contraction of uterine muscles during birth.

III. Grave's disease is caused by the malfunctioning of adrenal gland.

IV. ADH stimulates absorption of water and increases the urine production.

The correct option is B

I and II are true; III and IV are false

The correct option is B.

Explanation for the correct option:

1. Calcitonin is a polypeptide hormone produced by the parafollicular cells or C-cells of the mammalian thyroid gland.
2. The calcium ions concentration in the extracellular fluid is the chief stimulus for the C-cells to release calcitonin, which acts as an emergency hormone to protect against the development of hypercalcemia.
3. Oxytocin is known for its two main functions in the body: contractions of the uterus (womb) during childbirth and breastfeeding.
4. It stimulates contraction of the uterine muscles and also leads to an increase in the production of prostaglandins, which further increase contractions.

Explanation for the incorrect options:

Option A, C and D:

1. Grave's disease or exophthalmic goitre is an autoimmune disease that is caused due to hyperthyroidism (overactive thyroid gland).
2. It is caused due to over secretion of thyroid hormones and leads to bulging of eyeballs along with enlargement of thyroid gland.
3. ADH (antidiuretic hormone) or vasopressin is a posterior pituitary gland hormone.
4. It modulates the amount of water present in the body and its inadequacy leads to diabetes insipidus disorder.

Final answer: I and II are true; III and IV are false.