Hormones Flashcards
GHRH target/effect/inhibition
somatotroph, causes release of Growth Hormone, Somatostatin/IGF
GHIH(somatostatin)
Somatotroph Inhibits GH release, upregulated by IGF
Growth hormone is ihibited by
Somatostatin (GHIH,) positive feedback from IGF and Negative feedback to stop GHRH and GH from IGF and GH on Somatotropho to stop GH.
GH release is stimulated by
GHRH from Hypothalamus – Ghrelin from hypoglycemia **Thyrone hormone is required for action of growth hormone
GH transport and metabolism
pulsatile release, travels freely or bound to GHBP, eposidic release-1/2L~20min, Bound~50 min. Broken down in liver and excreted in urine.
IGF (Somatomedin C)
related structurally to pro insulin IGF 1 most important and responds to GH Have a long half life because they bind to IGF binding proteins
IGF actions
important for growth effects of GH,– promote linear bone growth,– increase organ size and function, –insufficient synthess of IGF’s can result in dwarfism,
Prolactin is stimulated by
lack of dopamine, TRH, estradiol inhibits dopamine, sensitizes to TRH.
prolactin secretion is inhibited by
dopamine from hypothalamus
Dopamine in hypothalamus MOA
binds to Gi on lactotroph and this decreases cAMP and calcium which will prevent release of prolactin, inhibited by estradiol
ADH secretion stimulated by
mediated via baroreceptors plasma osmolarity, if you have a 1-2% change Plasma Volume decrease in at least 10% of volume
ADH MOA
increase in cAMP causes aquaporins(AP2 only) to transport to luminal membrane
ADH second messenger
binds to V2 receptor increase cAMP (Gs) Binds to V1 recptor which increases IP3 and DAG(Gq)
ADH deficiency
Diabetes insipidus
Oxytocin secertion is upregulated by
a nursing baby, pressure against the cervix during birth
Oxytocin target cells
Smooth muscle cell in breasts in and uterus, causes contraction.
TRH triggers release of/is inhibited by
TSH in the anterior pituitary/Thyroid hormones
Thyrotropin releasing hormone is made up of
a tripeptide
TRH is secreted at/
a constant rate
Thyroid Stimulating hormone effects
promotes growth of thyroid gland, stimulates all steps of thyroid hormone synthesis. Tropic effect- trophic effect- increases size of gland.
TH is made from
iodination of tyrosine molecules grouped together in thryoglobulin
TH formation
- binding of TSH to receptor will cause syntehsis of thryoglobulin which contains tyrosine residues which is extruded onto the epical membrane
- Secondary active transport of Iodine into the cell with Na and extruded onto apical side of membrane
- oxidation of I which is catalyzed by TPO
- Iodination of thyroglobulin to form MIT or DIT (25%, more DIT)
- coupling of MIT DIT or DIT DIT
- TSH causes endocytosis of Thyroglopulin and will combine with lysoendosomes and split into T3 and T4, MIT, DIT
- enters circulation.
- MIT, DIT recycled.
Inhibition of TH synthesis
perchlorate, thyocyanate, nitrates,HIGH I- inhibit sodium iodine pump –PTU Propthiouracil, will inhiibt Oxidation, organification(wolf chykoff effect, high I inhibits.) and coupling.
TSH target for
antibodies, Stimulatory in graves, blocking in hashimotos.