Correct option is B
Explanation-
Statement analysis-
Statement A: They bind to cell surface receptors and influence stress adaptation - INCORRECT
Glucocorticoids (e.g., cortisol) are lipophilic steroid hormones. They do not bind to cell surface receptors. Instead, they diffuse through the membrane and bind to intracellular (cytoplasmic) receptors.
Statement B: They bind to intracellular receptors and influence stress adaptation - CORRECT
Glucocorticoids bind to cytoplasmic/nuclear receptors (glucocorticoid receptors). This complex translocates into the nucleus and modulates gene expression, influencing stress adaptation, metabolism, immune response, etc.
Statement C: They inhibit ACTH secretion from anterior pituitary - CORRECT
Glucocorticoids provide negative feedback to the hypothalamus and pituitary. This suppresses ACTH (Adrenocorticotropic hormone) secretion from the anterior pituitary, helping regulate cortisol levels.
Statement D: Prolonged treatment with glucocorticoids leads to atrophic and unresponsive adrenals - CORRECT
Exogenous glucocorticoids suppress endogenous ACTH due to feedback inhibition. Lack of ACTH leads to adrenal atrophy (especially zona fasciculata and reticularis), making adrenals unresponsive over time.
Statement E: Their secretion does not show circadian variations - INCORRECT
Cortisol secretion does show strong circadian rhythm. It is highest in early morning (~6–8 AM) and lowest at midnight. This rhythm is crucial for physiological homeostasis.
Final Correct Combination: B, C, and D
Correct answer: Option b
