Endocrine System & Obesity

Endocrine glands

Release chemical messengers (hormones) into the blood

Hypothalamus

Sends signals to the pituitary gland

Anterior pituitary

Receives signals from hypothalamus and sends further signals

Posterior pituitary

Releases hormones synthesized by hypothalamus

Negative feedback in endocrine regulation

End-product hormone suppresses further stimulation (e.g., thyroid hormones suppress TSH)

Upregulation

Increased receptor sensitivity and number

Downregulation

Decreased receptor sensitivity and number

Three main hormone conditions

Hormone deficiency, hormone excess, hormone resistance

Three levels of endocrine dysfunction

Primary (gland itself), Secondary (pituitary issue), Tertiary (hypothalamus issue)

Most important diagnostic tool for endocrine disorders

Immunoassays or blood hormone levels (e.g., TSH, T3, T4, urinary hormone levels)

Treatment for low hormone levels

Hormone replacement therapy (e.g., Prednisolone, Synthroid)

Treatment for high hormone levels

Suppression with medications, surgery, or radiation

Signs of hypopituitarism

Dwarfism, developmental delay, vision/neurologic issues, weakness, sluggishness, depression, weight changes, diabetes insipidus, hypotension, excessive urination and dehydration

Causes of hyperpituitarism

Pituitary adenoma, brain injury

Conditions of hyperpituitarism

SIADH (too much ADH), gigantism in children, acromegaly in adults

Hormone produced by pituitary to regulate thyroid

TSH (Thyroid Stimulating Hormone)

Causes of hypothyroidism

Gland destruction, autoimmune disease, low hormone production

Signs of hypothyroidism

Cold intolerance, weight gain, lethargy, fatigue, memory deficits, constipation, muscle cramps, decreased fertility, puffy face, hair loss, brittle nails, myxedema coma

Most common cause of hyperthyroidism

Graves' disease (autoimmune stimulation of thyroid)

Signs of hyperthyroidism

Exophthalmos, wide-eyed stare, periorbital edema, weight loss, heat intolerance, nervousness, tachycardia, insomnia, enlarged thyroid

Thyroid storm (thyrotoxic crisis)

Overwhelming release of thyroid hormones causing fever, tachycardia, agitation, psychosis; medical emergency

Parathyroid gland function

Secretes PTH when calcium is low; increases bone resorption, intestinal absorption, kidney reabsorption; raises serum calcium

Addison's disease

Adrenal insufficiency with low cortisol and aldosterone

Symptoms of Addison's disease

Weakness, hypotension, fatigue, anorexia, hypoglycemia, hyponatremia, hyperkalemia, tanned skin, loss of hair, amenorrhea

Cushing's disease vs. Cushing's syndrome

Disease: pituitary adenoma causing high ACTH. Syndrome: adrenal hyperfunction or exogenous steroids

Signs of hyperadrenalism (Cushing's)

Weight gain, moon face, buffalo hump, striae, easy bruising, poor healing, hirsutism, amenorrhea

Percentage of Americans overweight/obese

More than 65%

Factors contributing to obesity

Age, gender, race, socioeconomic status, conditions like Cushing's, PCOS, hypothyroidism

Adipocytes secretion

Secrete adipokines, which alter metabolism, insulin sensitivity, lipids, glucose production, and hunger/satiety

Treatments for obesity

Diet, exercise, medication, bariatric surgery