Drugs that affect the pituitary and hypothalamic hormones Flashcards
Review the releasing factors or memorize for the following hormones- – TSH – ACTH – LH and FSH – GH – Prolactin
– TRH (+) – CRH (+) – GnRH (+) – GHRH (+), SRIH (‐), other (+) – Dopamine (‐)
does somatostatin inhibit or increase pituitary release of hormones?
inhibit
IGF-1 is only used when?
in syndromes of GH resistance
What are the side effects of GH therapy?
mostly in adults
- peripheral edema
- carpal tunnel
- impaired glucose tolerance
- hypothyroidism
What are the side effects of GHRH?
injection site reactions an headaches
What are 2 syndromes of GH excess? what are their origins?
- Acromegaly (adult onset)
- Gigantism (childhood onset)
• Origins
– GH‐secreting adenomas (~80% of cases)
– Enhanced pituitary function (~20% of cases)
Why is it important for somatostatin agonists to be selective for receptor types 2 and 5?
This is important because other subtypes of
somatostatin receptors are present in the pancreas and
activation of these receptors results in the inhibition of
glucagon, insulin, and gastrin release.
What is the incidence of gallstones in somatostatin agonist use?
20-30%
how is pegvisomant able to block GH action?
Binds the receptor but does not allow dimerization
T-F–Prolactin is structurally homologous to
growth hormone, but the prolactin receptor
is not structurally homologous to the growth
hormone receptor.
False- both structurally homologous
What does prolactin stimulate? inhibit?
- lactation
2. reproductive functions
What is a very common cause of amenorrhea, galactorrhea, and female
infertility?
Hyperprolactinemia
What inhibits the release of prolactin?
hypothalamic dopamine
Vasopressin does what on V1 ? V2?
- V1 receptors in vascular smooth muscle:
vasoconstriction. - V2 receptors in renal tubule: increases
resorption of water.
When is vasopressin used?
Used as replacement therapy in diabetes insipidus
of pituitary origin
Low Ca2+ or PTH leads to what?
skin/live/kidney creating more vitamin D and thus increasing Ca
High Ca leads to what?
thyroid C cells releasing calcitonin and decreasing Ca
T-F–glucocorticoids onGI tract decrease serum calcium and glucocorticoids on bone increase serum calcium?
true
T-F–vitamin D is now associated with better prostate or breast health? how can it be administered?
- True
2. Oral or IM
What does calcitonin do?
hormone made in the C cells of
the thyroid. It inhibits bone resorption and
causes decreased serum calcium
How is calcitonin preparations given?
subQ, IM, nasal spray
What are bisphosphates taken up by? what does etidronate do? what do the amino bisphosphates do?
- osteoclasts
- retards the dissolution of
hydroxyapatite - inhibitors of
geranylgeranyl diphosphate synthase an enzyme
involved in isoprenoid biosynthesis. This leads to
an inhibition of bone resorption.
What are the 2 classes of osteoporosis?
- age-related, postmeopause
2. drug induced (glucocorticoids)
How do we prevent and treat osteoporosis?
- daily exercise
- diet and Ca intake, vit D
- prevent calcium mobilization from bone (bisphosphonates, calcitonin, raloxifene, estrogen/progestin combo post menopause)
How is denosumab administered? PTH/teriparatide?
injection
injection
What is the main difference between denosumab and PTH/teriparatide (forte)
the first stops osteoclasts, the 2nd stimulate`s osteoblasts
What are the 4 causes of hypocalcemia?
- Dietary calcium deficiency
- Vitamin D deficiency (nutritional rickets)
- Other forms of vitamin D deficiency or
resistance (metabolic rickets, osteomalacia) - Hormonal imbalances (hypoparathyroidism,
pseudohypoparathyroidism)
What is vitamin D mainly used for?
increase Ca absorption with calcium salts
What are the 4 causes of hypercalcemia?
- Hyperparathyroidism
- Ectopic PTH production
- Vitamin D excess
- Body immobilization
