Question

Given below are two statements:
Statement I: A reduction in the secretion of growth hormone (GH) is required for the survival of homeotherms during heat stress
Statement II: Acclimation to thermal stress is identified as a homeostatic process under endocrine control
In light of the above statements, choose the most appropriate answer from the options given below

• A. Both Statement I and Statement II are correct
• B. Both Statement I and Statement II are incorrect
• C. Statement I is correct but Statement II is incorrect
• D. Statement I is incorrect but Statement II is correct

Hint:

Endocrine Heat Stress Adaptations: Down-regulation of Growth Hormone (GH) and Thyroxine ($T_3/T_4$) lowers metabolic heat production. Cortisol, Aldosterone, and Prolactin rise.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Endocrine adaptations to severe thermal stress: metabolic down-regulation of calorigenic anabolic hormones (growth hormone, thyroxine) suppresses basal heat production to prevent lethal hyperthermia.

Step 2: Detailed Explanation:
1. Statement I: Growth Hormone (Somatotropin) and thyroid hormones ($T_3/T_4$) are potent calorigenic anabolic hormones that stimulate cellular metabolism and endogenous heat production. During severe environmental heat stress, homeotherms must minimize metabolic heat load; therefore, down-regulation and reduction in the secretion of Growth Hormone (GH) and thyroid hormones is an essential adaptive mechanism to lower metabolic heat production and survive. Hence, Statement I is correct.
2. Statement II: Physiological acclimation and acclimatization to thermal stress involves complex homeostatic neuroendocrine adjustments (HPA axis cortisol release, prolactin elevation, aldosterone electrolyte retention, and reduced thyroxine/GH). Hence, Statement II is correct.

Step 3: Final Answer:
Therefore, Both Statement I and Statement II are correct, matching option (A).