Question

Which of the following hormones have antagonistic (opposing) effects?
A. Thyroxine and calcitonin
B. Insulin and glucagon
C. Growth hormone and epinephrine
D. ACTH and glucocorticoids

Answer 1

Hormones are chemicals secreted directly into the bloodstream by specialized glands called endocrine glands. Hormones help in regulating various functions in our body like metabolism, regulation of blood sugar, growth and emergency responses.

Complete answer:
Option (a) is incorrect. Thyroxine and calcitonin are secreted by the thyroid gland. Thyroxine helps to regulate the basal metabolism of the body, protein synthesis, growth and vitamin metabolism. Thyroxine affects almost all the cells in the body. Calcitonin, on the other hand, regulates calcium and phosphorus metabolism. It is known to counteract the function of Parathormone or PTH (secreted from the Parathyroid gland).
Option (b) is correct. Insulin and Glucagon are secreted from the beta and alpha cells of the pancreas. These two hormones work antagonistically to regulate the levels of sugar in blood. While insulin acts to decrease the blood sugar level, glucagon works to increase it. This interplay between the two hormones helps to keep normal levels of blood sugar.
Option (c) is incorrect. Growth hormone is synthesized and secreted by the anterior pituitary gland. This hormone actively regulates cell development and growth in humans. On the other hand, epinephrine is secreted by the adrenal glands. It functions as a neurotransmitter and helps to regulate the fight or flight response in human beings.
Option (d) is incorrect. ACTH or Adrenocorticotropic hormone is secreted by the anterior pituitary gland. It functions to regulate the circadian rhythm and production of cortisol from the adrenal glands. Glucocorticoids are steroid hormones that are secreted from the adrenal glands. Glucocorticoids are an integral part of both the immune system and the metabolic system of the body. As a part of the immune system it helps in regulating anti-inflammatory proteins. It also helps in glucose metabolism and inhibits dehydration.

Hence, the correct answer is option (B).

Note: Hormones are secreted from endocrine or ductless glands. They are secreted into the bloodstream and are carried by blood to their respective target organs. Antagonistic hormones are a pair of hormones that function in opposites. Glucagon and insulin are antagonistic hormones. Glucagon functions to increase blood sugar levels and insulin works to decrease the same.