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12 Cards in this Set
- Front
- Back
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GH secretion is regulated by (3)
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growth hormone releasing hormone (GHRH)
somatostatin ghrelin |
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GHRH, somatostain and ghrelin activate
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G-protein-coupled receptors in pituicytes
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GH secretion is stimulated by (7)
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deep sleep ("need sleep to grow")
exercise sex steroids fasting/hypoglycemia amino acids alpha-adrenergic stress |
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GH secretioin in inhibited by
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IGF-1
obesity glucocorticoids hyperglycemia free fatty acids beta-adrenergic |
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function of IGF-1
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stimulates growth by:
-stimulating clonal expansion of early chondrocytes -stimulating chondrocyte maturation |
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IGF-1 imposes negative feedback on (3)
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anterior pituitary (decreased release of GH)
arcuate nucleus (decreased release of GHRH) somatostatin |
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pathological causes of short stature (6)
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hypopituitarism
GH insensitivity (point mutation or deletion in GH receptor) aka "Laron Syndrome" short ancestors ("familial" or "genetic" short stature) constitutional delay of growth and puberty ("late bloomer") intrauterine growth retardation (IUGR) genetic syndromes (Turner Syndrome, Down Syndrome) |
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clinical findings for GH insensitivity (3)
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normal or high [GH]
low [IGF-1] (GH binds to GH receptors on liver to stimulate IGF-1 synthesis) low size |
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clinical findings for constitutional delay of growth and puberty (3)
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delayed bone age
delayed onset of puberty normal adult height (when finished growing) |
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Turner syndrome patients with isochromosome Xp are _____ and ____
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normal height (SHOX locus is on Xp)
infertile (ovary-determining region is on Xq) |
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Turner syndrome patients with isochromosome Xq are ____ and _____
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short (SHOX locus is on Xp)
fertile (ovary-determining region is on Xq) |
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endocrine causes of short stature (4)
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hypothyroidism
GH deficiency Cortisol excess (e.g., Cushing's disease - moon face, Buffalo hump) congenital adrenal hyperplasia (leads to precocious puberty - tall stature as children due to increase in androgen, but then short stature due to premature epiphyseal fusion) |
