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2.6 Receptor Regulation & Integration — Test 1
Q1. Downregulation of receptors occurs when a hormone:✓ Decreases the number or affinity of receptors for itself or another hormone
Q2. In the ovary, estrogen upregulates its own receptor and the receptor for:✓ LH
Q3. In the uterus, progesterone downregulates:✓ Its own receptor and the estrogen receptor
Q4. Insulin regulates its own receptors such that receptor number is:✓ Increased in starvation and decreased in obesity
Q5. If GnRH is given continuously at a constant (non-pulsatile) rate, LH secretion:✓ Rises at first, then falls (receptor downregulation)
Q6. The condition in which one hormone at pathologically high levels mimics another by binding its receptor is:✓ Specificity spillover
Q7. ACTH, in addition to stimulating cortisol synthesis, also:✓ Upregulates its own receptor (increasing adrenal sensitivity)
Q8. Match each hormone with its receptor-regulation effect and choose the correct option.✓ A-ii, B-iii, C-i
Q9. Pulsatile (versus constant) GnRH secretion is important because:✓ Pulsatile delivery sustains gonadotropin release; constant delivery suppresses it
Q10. Thyroid hormone increases the heart's responsiveness to catecholamines by upregulating:✓ beta1-adrenergic receptors in the heart
Q11. Rapid loss of responsiveness to a hormone after repeated/continuous stimulation is called:✓ Tachyphylaxis (desensitization)
Q12. A hormone that has little effect alone but is required for another hormone to act fully is showing a:✓ Permissive effect
Q13. After binding their hormone, some peptide-hormone receptors are taken into the cell by endocytosis, where they may be:✓ Degraded by lysosomes or recycled to the membrane
Q14. Insulin resistance in obesity/type 2 diabetes is partly explained by:✓ Downregulation of insulin receptors (fewer/less sensitive)
Q15. Glucocorticoids maintain blood pressure partly by a permissive action on vessels, specifically by:✓ Upregulating alpha1 receptors on arterioles
Q16. A constant high level of GnRH agonist is used clinically to:✓ Suppress LH/FSH and sex-steroid production (after an initial flare)
Q17. The term for two hormones together producing a greater effect than the sum of their separate effects is:✓ Synergism
Q18. High circulating insulin acting on IGF-1 receptors (because of structural similarity) is an example of:✓ Specificity spillover
Q19. Which best illustrates UPregulation of a receptor?✓ Estrogen increasing LH receptors before ovulation
Q20. Glycyrrhetinic acid (from licorice) causes apparent mineralocorticoid excess by inhibiting 11beta-HSD2, thereby allowing:✓ Cortisol to act on mineralocorticoid receptors (specificity spillover)