What is Which of the following results in increase ADH activity? and explain in detail?
One of the stimuli for causing intense ADH secretion is decreased blood volume. This occurs strongly when the blood volume decreases 15 to 25 percent or more. ADH is considerably more sensitive to small changes in osmolarity than to similar percentage changes in blood volume. There are at least three kinds of vasopressin receptors: V1A, V1B, and V2. All are G-protein-coupled. V1A in blood vessels: causes vasoconstriction IP3-Ca2+ pathway V1B in anterior pituitary: causes ACTH release IP3-Ca2+ pathway V2 in late distal tubule and collecting duct: increases expression of aquporin-2 and urea transpoers at basolateral membrane cAMP pathway.