Question

A tadpole with surgically removed thyroid gland can be made to metamorphose if

• A. Given an injection of TSH
• B. Given an injection of oxytocin
• C. Given an injection of thyroxine
• D. Fed on dried thyroid gland

Answer 1

The correct option is C Given an injection of thyroxine

• TSH (Thyroid stimulating hormone) is secreted from anterior lobe of pituitary gland and stimulates growth and functioning of thyroid gland.
  
• Oxytocin is secreted from the posterior pituitary and helps in the contraction of uterus during childbirth and also stimulates release of milk from mammary glands i.e. lactation.
• Thyroxine is secreted from thyroid gland. It stimulates the consumption of oxygen by metabolically active tissues and also increases the oxidation of glucose in tissues.
  

In frogs, growth and metamorphosis (development of frog from tadpole stage to adult stage) is regulated by thyroxine gland. Hence, a tadpole with surgically removed thyroid gland can be made to metamorphose if given an injection of thyroxine.

So, the correct answer is 'Given an injection of thyroxine'.