Exam 1 Flashcards
chemical messenger system comprising of feedback loops of hormones released by internal glands of the body directly into the blood, regulating distant target organs, functions to maintain homeostasis through the release of hormones by endocrine glands, works together with autonomic nervous system and is integrated by the hypothalamus
endocrine system
chemical synthesized by certain cells and released directly into the blood, produces its effect on cells distant from the site of release
hormones
short or long chains of linked amino acids, water soluble, all pituitary hormones and hypothalamic releasing factors EXCEPT dopamine
peptide and protein hormones
derived from cholesterol, fat soluble, cortisol, testosterone, estradiol
steroid hormones
amino acids with modified groups, water or fat soluble, thyroid hormones, epinephrine, dopamine
amine hormones
cell surface receptors for peptide and water soluble amines that interact with cell surface receptors, signal transduction via second messengers, alteration in cell activity, quick onset and short duration of action
receptors for water soluble hormones
nuclear receptors for steroid and thyroid (fat soluble amine) hormones that diffuse through the plasma membrane, hormone binds with receptor in cytoplasm forming a receptor hormone complex, receptor hormone complex enters the nucleus and triggers gene transcription, transcribed mRNA is translated into proteins that alter cell activity, late onset (because has to make protein) and long duration of action
receptors for lipid soluble hormones
master regulators of the endocrine system
hypothalamus and pituitary
______ produces releasing factors that regulate the following _______ hormones:
1. Growth hormone (GH)
2. Prolactin (PRL)
3. thyroid stimulating hormone (TSH)
4. adrenocorticotropic hormone (ACTH)
5. follicle stimulating hormone (FSH)
6. luteinizing hormone (LH)
hypothalamus, anterior pituitary
________ releases two hormones that are synthesized by the _________:
1. vasopressin
2. oxytocin
posterior pituitary, hypothalamus
- replacement therapy for hormone deficiency states
- antagonists for diseases that result in hypersecretion
- diagnostic tools for identifying endocrine abnormalities
drugs to treat hypothalamic and pituitary disorders
- hypothalamus releases growth hormone releasing hormone (GHRH) which ____________ GH release and somatostatin which __________ GH release
- anterior pituitary –> GH release by GHRH
- liver –> GH ________ IGF-1 production
stimulates, inhibits, stimulates
GH has negative feedback on which endocrine gland?
pituitary
IGF-1 has negative feedback on which endocrine glands?
pituitary and hypothalamus
releasing factor secreted by the hypothalamus to stimulate GH secretion from anterior pituitary
growth hormone releasing hormone (GHRH)
- synthetic N-terminally modified form of human GHRH, resistant to degradation for prolonged duration of action (whereas giving human GHRH easily broken down by enzymes) to increase GH and IGF-1
- clinical use is for reduction of excess abdominal fat in HIV-associated lipodystrophy but not for GH deficiency
- administered SC
- adverse effects: hypersensitivity, joint pain/arthralgia, muscle pain/myalgia, peripheral edema, hyperglycemia, injection site reactions
tesamorelin acetate (EGRIFTA SV)
how must all peptide hormones be administered?
SC
- peptide hormone secreted by somatotroph cells of anterior pituitary, most abundant pituitary hormone that is released in a pulsatile fashion, maximal at night at deep sleep, other stimuli include high protein meals, exercise, stress, hypoglycemia
- in childhood/adolescence this is required for attainment of normal size (deficiency in childhood means dwarfism)
- in adult life has important effects on carbohydrate/lipid metabolism and on lean body mass and bone density
- effects of this are mediated by IGF-1 released from the liver
growth hormone (GH)
increased glucose synthesis and release which increased blood glucose (can lead to hyperglycemia), increased lipolysis (fat breakdown), stimulates protein synthesis for increased muscle growth, increased longitudinal growth until puberty, increased bone mineral density after puberty
pharmacological effects of GH
short stature and low growth rate caused by decreased GHRH for hypothalamic version of this or decreased GH for pituitary version of this, proportional decrease in size of all body parts, treatment includes somatropin (GH analog)
dwarfism
inherited, relatively rare, defective GH receptors in liver (inadequate IGF-1 production), like the other form but plasma GH levels are normal or increased whereas IGF-1 levels are decreased, liver can’t produce IGF-1 b the because GH receptors on the liver are defective, treatment includes mecasermin (IGF-1 analog)
Laron dwarfism
- recombinant human GH preparations that are modified in some way to decrease breakdown by enzymes, restores normal growth and metabolism in GH-deficient individuals
- clinical uses: replacement therapy as daily SC injection for GH deficiency in children (varies in adults) or to treat AIDS-induced wasting syndrome which is a severe loss of muscle mass due to AIDS (because GH increases muscle mass)
- adverse effects: well tolerated, rare intracranial hypertension, arthralgia, myalgia, peripheral edema, HYPERGLYCEMIA main adverse effect –> SHOULD NOT be given to patients with active malignant tumors or a history of recurrent tumor growth
somatropin (HUMATROPE, NUTROPIN, GENOTROPIN)
- MOA: recombinant IGF-1 analog that stimulates IGF-1 receptors and improves growth (bone) and metabolic effects (increased muscle mass, decreased body fat) mediated by IGF-1
- clinical use: replacement therapy as SC injection in iGF-1 deficiency/Laron dwarfism that is not responsive to exogenous GH
- adverse effects: hypoglycemia (because IGF-1 analog and IGF-1 is insulin like and insulin causes hypoglycemia), rare intracranial hypertension –> to AVOID HYPOGLYCEMIA, patients should take with a carbohydrate containing meal/snack 20 minutes before or after taking drug –> SHOULD NOT be given to patients with active malignant tumor or history of recurrent tumor growth
mecasermin (INCRELEX)
- excessive secretion of GH (usually from pituitary adenoma –> tumor)
- before puberty causes gigantism in children (person is very large but proportional)
- after puberty acromegaly in adults, disproportionate growth of the body due to bone thickening not getting any longer, slow onset
- treatment options: transsphenoidal surgical resection, radiation therapy, pharmacological includes drugs that inhibit GH secretion (somatostatin analogs, dopamine agonists) or block GH action (GH receptor antagonist) –> pharmacological therapy is considered when surgery or radiation is contraindicated
syndromes of GH excess