CH 26 Hormonal Regulation of Tubular Reabsorption and Tubular Secretion

angiotensin II

low blood volume or low blood pressure stimulate renin-induced production of this hormone

angiotensin II

stimulates activity of Na+/H+ antiporters in proximal tubule cells

angiotensin II

increases reabsorption of Na+, other solutes and water, which increases blood volume

aldosterone

increased angiotensin II level and increased level of plasma K+ promote release of this enzyme by adrenal cortex

aldosterone

enhances activity of sodium-potassium pumps in basolateral membrane and Na_ channels in apical membrane of principal cells in collecting duct

aldosterone

increases secretion of K+ and reabsorption of Na+, Cl-; increases reabsorption of water, which increases blood volume

anitdiuretic hormone (ADH)

increased osmolarity of extracellular fluid or decreased blood volume promotes release of this hormone from the posterior pituitary gland

anitdiuretic hormone (ADH)

stimulates insertion of water-channel proteins (aquaporin-2) into the apical membranes of principal cells

anitdiuretic hormone (ADH)

increases facultative reabsorption of water, which decreases osmolarity of body fluids

atrial natriuretic peptide (ANP)

stretching of atria of heart stimulates secretion of this hormone

atrial natriuretic peptide (ANP)

suppresses reabsorption of Na+ and water in proximal tubule and collecting duct; also inhibits secretion of aldosterone and ADH

atrial natriuretic peptide (ANP)

increases excretion of Na+ in urine (natriuresis); increases urine output (diuresis) and thus decreases blood volume

parathyroid hormone (PTH)

decreased level of plasma Ca2+ promotes release of this hormone from parathyroid glands

parathryoid hormone (PTH)

stimulates opening of Ca2+ channels in apical membranes of early distal tubule cells

parathryoid hormone (PTH)

increases reabsorption of Ca2+