1) Endocrine gland receives signal from neuron or another gland's hormone.

2) Hormone is released into blood stream.

3) Hormone travels body, binding receptors on/in target cells.

4) Hormone binds to cell receptor: Steroid & others can go through plasma membrane; have receptors inside the cell, many inside nucleus (associated with chromatin). Others bind to plasma membrane receptors.

Effect - may change rate of reactions, stimulate target cell to take up/release materials, regulate DNA transcription, and protein synthesis.

Follicle-stimulating hormone (peptide). Released by anterior lobe of pituitary. Targets: Ovaries - stimulates development of ova and follicles that contain them. Testes - stimulates sperm production.

[level is higher after menopause]

Luteinizing hormone (peptide). Released by anterior lobe of pituitary. Targets: Ovaries - stimulates ovulation; stimulates release of estrogen and progesterone (important to pregnancy). Testes - Stimulates release of testosterone.

[LH level peaks before menstruation and in the middle of the cycle (ovulation)]
[ovulation test kits detect LH to predict fertility]

Thyroid-stimulating hormone or thyrotropin (peptide). Released by anterior lobe of pituitary. Stimulates growth of thyroid gland and release of thyroid hormone.

[TSH levels are tested to see if a person has too much or too little thyroid hormone]
[only 3 amino acids long]

Adrenocorticotropic hormone or corticotropin (peptide). Released by anterior lobe of pituitary. Stimulates adrenal cortex of adrenal glands to secrete their hormones, especially cortisol. Central to body's response to stress.

[also triggers release of GH]
[plays a role in the body’s response to stress]
[leads to changes in metabolism of carbs, fats, and proteins, see effects of cortisol]

Prolactin (peptide). Levels rise during pregnancy, and after birth it stimulates mammary glands to synthesize milk. In males it makes testes more sensitive to LH; indirectly enhancing release of testosterone.

[increases testosterone secretion in men]
[casues the feeling of satisfaction following sex]

Growth hormone or somatotropin (peptide). Generally promotes mitosis and cellular differentiation: widespread tissue growth. Especially bone, cartilage, muscle, and fat. Directly stimulates tissues, but it also causes the liver and other tissues to produce growth stimulants (IGF-I & II, somatomedins). Increases protein synthesis and metabolism of fats.

[1000x more GH produced than any other pituitary hormone]
[many controversial uses: MS, fibromyalgia, Crohn’s disease, aging, obesity, etc]
[very short half-life of 6-20 minutes]
[high protein meals increase GH, high carb meal suppress GH]

Oxytocin (peptide). Causes smooth muscle of the uterus to contract, helping to expel the infant during labor. Causes mammary glands to squeeze milk into the ducts and to the nipple.

[Pitocin given to induce labor is a brand name for synthetic oxytocin]

[OT in the brain can cause sexual arousal, maternal behavior, and increased trust]

Antidiuretic hormone or vasopressin (peptide). Acts on kidneys, increasing water retention, reducing urine volume, and helps prevent dehydration.

[causes vasoconstriction at high concentrations]
[functions as a neurotransmitter when released into junctions between neurons]
[some tumors and infections lead to increased levels of ADH]

Thyroid hormone (monoamine). Refers to both T₃ and T₄. Released in response to TSH. Primarily increases the body's metabolic rate. Increases oxygen consumption; has calorigenic effect (heat production); increases appetite, breakdown of carbs, fats, and protein for fuel; promotes alertness, bone growth and remodeling, development of skin, hair, nails, and teeth.

[increases oxygen use, heart/respiratory rate, appetite, alertness, bone growth, body heat]
[stimulates pituitary gland to release GH]
[iodine is required to make the thyroid hormone]
[too much (hyperthyroidism) or too little (hypothyroidism) thyroid hormone is a problem]

(peptide) Released by thyroid when blood calcium is high. Promotes bone growth to store calcium.

[prevents bone loss in pregnant and lactating women]
[very important in children but doesn’t have much effect on adults]
[may use calcitonin from fish as a future treatment for osteoarthritis]
[calcitonin structure is 32 amino acids that form a single alpha helix]

Parathyroid hormone (peptide). Released by parathyroid in response to hypocalcemia. Raises blood calcium by: promoting calcitriol (form of vitamin D₃) synthesis, which promotes intestinal absorption of calcium; inhibiting urinary calcium secretion; indirectly stimulating osteoclasts to reabsorb calcium from bones.

[increases synthesis of calcitriol (vitamin D) to absorb more calcium]
[may be removed with the thyroid gland in cases of hyperthyroidism, causes drop in Ca]
[binds to receptors in the membrane and activates second messenger system in cell]

(peptide) Released by pancreas in response to high blood glucose. Increases uptake to glucose (and other nutrients) into cells, use of glucose, and storage of glucose (glycogen).

[two men who discovered how to extract insulin received the 1923 Nobel prize]
[insulin means “island” in latin, referring to the islets of Langerhans]
[not producing insulin or resistance to insulin causes diabetes]
[binds to receptors in the membrane and brought in by receptor-mediated endocytosis]

(monoamine) Released from adrenal medulla in response to the activation of the sympathetic nervous system. Increases heart rate, breathing, blood pressure, and decreases digestion in preparation for fight-or-flight.

[also act as neurotransmitters, also known as adrenaline/noradrenaline]
[increase alertness and anxiety, decrease insulin secretion]
[epinephrine can treat bronchial asthma and acute allergies]
[epinephrine can be injected directly into a stopped heart to restart the heartbeat]

(steroid) Released by adrenal cortex. Stimulates kidneys to retain sodium and excrete potassium. Maintains blood pressure/volume.

[pregnant women may have higher levels of aldosterone]
[may be an important supplement to the action of coritsol]
[helps regulate water balance and urine output]
[loss of aldosterone can lead to death within days]

(steroid) Released by adrenal cortex. Adapts the body to long term stress, increases blood pressure and blood glucose level, anti-inflammatory effect helps repair tissues, but suppresses immune system. Stimulates gluconeogenesis and use of alternative energy sources

[used to treat many conditions – rheumatoid arthritis, depression, stress, trauma,etc]

[after long stress, cortisol levels don’t return to normal, causes chronic stress]

(steroid) Released by adrenal cortex. Promotes growth of pubic and axillary hair, bone growth, sex drive, and male prenatal development.

[this is the source if testosterone in women and estrogen in men]

[androgen is required for a male fetus to develop male genetalia]

[insensitivity to androgen may cause infertility and intersexuality]

(steroid) Estrogen released by ovaries. stimulates development of female reproductive organs & secondary sex characteristics; stimulates bone growth.

[estrogen treatment can increase the risk of breast cancer, heart disease, and stroke]

[50% of breast cancers depend on estrogen for continued growth]

(steroid) Released by ovaries. Regulates the menstrual cycle and pregnancy.

[increases energy and calms anxiety]

[increases the core body temperature during ovulation]

[used to support difficult pregnancies or to prevent pregnancy in birth control pills]

[prepares mammary glands for lactation]

(steroid) Released by testes. Stimulates development of male reproductive organs & secondary sex characteristics; stimulates bone growth.

[increases energy, red blood cells, libido, aggression]