Untitled Flashcards Set

TABLE 17.4

Hormones from Sources Other Than the Hypothalamus and Pituitary

Source

Hormone

Target Organs and Tissues

Principal Effects

Pineal gland

Melatonin

Brain

Thymus

Thymopoietin, thymosin, thymulin

Immune cells (T lymphocytes)

Uncertain; may influence mood and sexual maturation

Stimulate T lymphocyte development and activity

Thyroid gland

Thyroxine (T4) and triiodothyronine (T3)

Calcitonin

Parathyroid glands

Most tissues

Bone

Elevate metabolic rate and heat production; increase respiratory rate, heart rate, and strength of heartbeat; stimulate appetite and accelerate breakdown of nutrients, promote alertness and quicken reflexes; stimulate growth hormone secretion and growth of skin, hair, nails, teeth, and fetal nervous system

Stimulates bone deposition, mainly in children

Parathyroid hormone (PTH)

Bone, kidneys, small intestine

Raises blood Ca2+ level by stimulating bone resorption and inhibiting deposition, reducing urinary Ca2+ excretion, and enhancing calcitriol synthesis

Adrenal medulla

Epinephrine, norepinephrine, dopamine

Most tissues

Adrenal cortex

Aldosterone

Pancreatic islets

Kidney

Cortisol and corticosterone

Most tissues

Dehydroepiandrosterone

Glucagon

Bone, muscle, integument, brain, many other tissues

Primarily liver

Promote alertness; mobilize organic fuels; raise metabolic rate; stimulate circulation and respiration; increase blood glucose level; inhibit insulin secretion and glucose uptake by insulin-dependent organs (sparing glucose for brain)

Promotes Nat and water retention and K+ excretion; maintains blood pressure and volume

Stimulate fat and protein catabolism, gluconeogenesis, stress resistance, and tissue repair

Precursor of testosterone; indirectly promotes growth of bones, pubic and axillary hair, apocrine glands, and fetal male reproductive tract, stimulates libido

Stimulates amino acid absorption, gluconeogenesis, glycogen and fat breakdown; raises blood glucose and fatty acid levels

Insulin

Most tissues

Stimulates glucose and amino acid uptake; lowers blood glucose level; promotes glycogen, fat, and protein synthesis

Somatostatin

Stomach, intestines, pancreatic islet cells

Modulates digestion, nutrient absorption, and glucagon and insulin secretion

Gastrin

Stomach

Stimulates acid secretion and gastric motility