Question

Which of these hormones are not secreted by an endocrine gland?
A. ADH
B. PTH
C. \[{T_4}\]
D. ANF

Answer 1

Hint: Endocrine glands are ductless glands of the endocrine system that secretes different products and hormones directly into the blood. Some major glands of the endocrine system are pineal, pituitary glands, ovaries, testes, thyroid glands, parathyroid glands, hypothalamus, and adrenal glands. This hormone is secreted by the heart atrium.

Complete answer: Antinatriuretic factor (ANF) is a polypeptide hormone-containing 28 amino acids. It is secreted by the atria of the heart in response to atrial stretch. It primarily acts on the kidney to increase sodium excretion and glomerular filtration rate (GFR) to antagonize renal vasoconstriction and inhibits renin secretion. It helps in antagonizing vasoconstriction and helps in shifting fluid from the intravascular to the interstitial compartment. It also acts as an inhibitor of aldosterone synthesis in the adrenal gland. It participates in the natriuretic response to acute and chronic overload. When the number of nephrons is reduced then, it acts as a physiological modulator of GFR. Antidiuretic peptide (ANP) or antidiuretic factor (ANF) is encoded by the NPPA gene. They are the paracrine factor that causes a reduction in expanded extracellular fluid (ECF) volume by increasing sodium excretion.
Hence, the correct answer is option D.

Note: In case of the cardiovascular system, it antagonizes vasoconstriction and moves the fluid from the intravascular to the interstitial compartment. It also acts as a powerful inhibitor of aldosterone synthesis. It also participates in the natriuretic responses to volume overload which can be acute as well as chronic.