Foundations Hormones

ADH (antidiuretic hormone)

Secreted by: posterior pituitary; Stimulus: increased serum osmolality (dehydration), low blood volume; Target tissues: kidney distal tubules and collecting ducts; Reaction: conserves water, decreases urine output (alcohol inhibits ADH)

Aldosterone

Secreted by: adrenal cortex; Stimulus: decreased serum sodium, increased serum potassium, angiotensin II; Target tissues: kidney distal tubules; Reaction: retains sodium (and water), excretes potassium

ANP (atrial natriuretic peptide/factor)

Secreted by: cells in the atria; Stimulus: increased atrial pressure/stretch (e.g., heart failure); Target tissues: kidney tubules; Reaction: rapid diuresis, sodium excretion, blocks ADH and aldosterone

Renin

Secreted by: kidneys (juxtaglomerular cells); Stimulus: decreased GFR/renal blood flow, low BP; Target tissues: angiotensinogen in the blood, converted to angiotensin II, which acts on blood vessels and the adrenal cortex; Reaction: vasoconstriction and aldosterone release, raising BP and volume

Angiotensin II

Secreted by: formed in the blood from angiotensin I (via ACE, mainly in the lungs); Stimulus: renin release from low renal perfusion; Target tissues: blood vessels, adrenal cortex, hypothalamus; Reaction: vasoconstriction, aldosterone release, thirst and ADH release

Parathyroid hormone (PTH)

Secreted by: parathyroid glands; Stimulus: decreased serum calcium; Target tissues: bone (osteoclasts), kidneys, intestine (via vitamin D); Reaction: raises serum calcium, kidneys excrete phosphorus

Calcitonin

Secreted by: thyroid gland; Stimulus: increased serum calcium; Target tissues: bone (osteoclasts), kidneys; Reaction: lowers serum calcium by inhibiting bone breakdown and increasing renal calcium excretion

Epinephrine and norepinephrine (catecholamines)

Secreted by: adrenal medulla (via sympathetic nervous system); Stimulus: stress, shock, low cardiac output; Target tissues: heart (beta-1) and blood vessels (alpha-1); Reaction: increased HR and contractility, widespread vasoconstriction, blood shunted to vital organs

Erythropoietin

Secreted by: kidneys; Stimulus: hypoxia or anemia; Target tissues: bone marrow; Reaction: increased red blood cell production