Endo week 6 Flashcards
hormones that increase GH secretion?
Hint: A.C.I.D.T.E
hormones that increase GH secretion?
(Hint: A.C.I.D.T.E)
Androgens Catecholamines Insulin Dopamine (by decreasing GHIG) Thyroid hormone Estrogen
when are the 2 period of rapid growth?
when are the 2 period of rapid growth?
1: infancy
2: late puberty
what happens in African pygmies?
what happens in African pygmies?
Answer:
- IGF-1 concentration does not increase at puberty.
- A low reduction of GH-BP
- A partial defect in GH receptors
what are the steps involved in Bone growth when GH is involved?
what are the steps involved in Bone growth when GH is involved?
step 1.
GH stimulates chondrocytes to synthesize and respond to IGF-1 (autocrine and paracrine)
step 2.
Chondrocytes make cartilage matrix and calcifies it.
step 3.
Osteoblast migrate to calcified matrix and solidify the cartilage into bone
Growth hormone is a __________ hormone and causes Diabetes _______ when it is in excess.
Growth hormone is a __Diabetogenic__ hormone and causes Diabetes __Mellitus_____ when it is in excess.
Diabetogenic because it causes insulin insensitivity.
why is it hard to detect GH abuse?
why is it hard to detect GH abuse?
- GH is naturally secreted in pulsatile manner
- GH is secreted during low level of stress
- GH is stimulated by exercise
- GH is increased if high protein diet
- GH has small half-life (18-20minutes)
- exogenous GH cannot be distinguished from endogenous GH
Ghrelin is produced by ____?
Ghrelin is produced by ____?
Answer: the stomach and increases gastric secretion and motility.
largest secretion of GH occurs when?
A. early morning
B. 1 hr after sleep
C. 10:00pm
D. pulsatile manner throughout the day
largest secretion of GH occurs when?
Answer: B, 1hr after falling asleep
does GH play a role in regulating the serum Na+ levels?
does GH play a role in regulating the serum Na+ levels?
Answer: yes
does Thyroid hormone alone have an effect on Growth
does Thyroid hormone alone have an effect on Growth
Answer: no, it needs GH to work synergistically with it
Galactorrhea, seen in some acromegaly patients is due to the increased release of _____?
Galactorrhea, seen in some acromegaly patients is due to the increased release of ___Prolactin___?
a fusion of epiphysis at the time of puberty is due to increased levels of ______?
a fusion of epiphysis at the time of puberty is due to increased levels of ___Estrogen___?
IGF’s are transported in the serum bound to ______?
IGF’s are transported in the serum bound to ___Insulin-like growth factor-binding proteins____?
the important site of IGF-1 production is in the ?
the important site of IGF-1 production is in the ?
Answer: liver
what is the insulin like activity of IGF-1?
what is the insulin like activity of IGF-1?
Answer: Protein synthesis
is GH structurally similar to prolactin?
is GH structurally similar to prolactin?
Answer: yes
what are the things in Laron Dwarfism?
hint: L.O.N.G
Laron Dwarfism:
- Less GH-binding protein
- nO IGF produced
- Normal/high levels of GH
- Genetic defect in GH receptor
what happens in African Pygmy?
African Pygmy:
- decreased IGF-1 formation
- No IGF-1 increase at puberty
- GH is normal
what happens in Gigantism?
Gigantism:
- Excess GH before puberty
- Taller and heavier b/c GH increase before epiphyseal plate fuse.
- Glucose intolerance & hyperinsulinemia
- Cardiovascular problems
what happens in Acromegaly?
Acromegaly:
- Excess GH after epiphyses close (after puberty)
- Bone grow sideways
- Soft tissue growth
- Cardiovascular problems
- Prognathism; big nose, ear, mandible, hand, feet.
what is the half-life of GH and that of IGF-1
what is the half-life of GH and that of IGF-1
Answer:
GH is 20 mints
IGF-1 is 20 hours
