Adrenal, Pituitary, GH 8.23 Flashcards
Cushing’s Syndrome
Increased glucocorticoid activity in the blood 1. Exogenous - glucocorticoid therapy 2. Endogenous - excess cortisol from the adrenal gland Sx include: moon face, red cheeks, excessive weight gain in abdomen, striae, depression
Sub-types of Cushing’s
ACTH Dependent Pituitary tumor making ACTH Ectopic tumor making ACTH ACTH Independent Adrenal tumor making cortisol in the absence of ACTH
Two thyroid hormones
T3: 3 Iodines, less produced, more potent, long half life (around 1 day) T4: 4 Iodines, more produced, less potent, long half life (around 6 days)
Effect of Thyroid Hormones
Increase metabolism Increase cardiovascular output/rates Contribute to growth Many other systems…
Thyroid Hormone Feedback Loop
Disease of too little thyroid hormone
Too little – hypothyroidism
– 1o – low fT4; high TSH (e.g. Hashimoto’s thyroiditis) (goiter symptoms)
– 2o – low fT4; TSH not elevated (hypopit) (atrophied thyroid)
Disease of too much thyroid hormone
Too much – hyperthyroidism
– Almost always 1o hyperthyroidism
– TSH-secreting tumors (secondary hyperthyroidism) are VERY rare
– High fT4; low TSH (e.g. Graves’ disease)
Stimulants of GH
Amino Acids
Hypoglycemia
Exercise
Stage 3/4 Sleep
Gonadal Steroids/thyroid hormone
Inhibitors of GH
Glucose
GH
IGF-1
Cortisol
Feedback loop of GH
Diseases of too much GH
Too much – almost always due to pituitary GH-secreting tumor.
– Before puberty – gigantism
– After puberty – acromegaly
Diseases of too little GH
Too little – Growth hormone deficiency
– Children – short stature
– Adults – controversial
Screening test for GH excess
Test for IGF1
Tx for GH excess
Surgery
Screening for low GH
Stimulation tests with Arg, or sleep study
Tx for low GH
Recombinant human GH
