3.1.1 Growth Hormone and Prolactin Physiology Flashcards
What are some conditions that increase the amount of GHRH, which upreagulates somatotrophs?
GalphaS (adenylate cyclase and cAMP)
Ca++
What is used to sequester IGF1? In what form does IGF interact with target tissues?
IGFBP; unbound
What are some mutations that can alter the axis of GH?
What are some other mutations within the GH axis that can lead to growth abnormalities?
Describe the positive and negative feedback loops mediated by IGF-1 throughout the GH cascade.
What role do estrogens/androgens play in the regulation of growth?
Positive via the induction of GH and IGF-1
Negative via epiphyseal plate closure
Describe the regulation of prolactin and its unique characteristic within the anterior pituitary.
Prolactin is upregulated by PRH and downregulated by dopamine. It is unique in that it is under dominant negative regulation.
Prl secretion can lead to what condition?
Amenorrhea
What are three possible treatment mechanisms for GH excess?
Dopamine agonists
Somatostatin analogs
GH antagonists
What stimulates milk production? propels milk?
Production: Prl
Propels milk: Oxytocin
What role do glucocorticoids play in the regulation of growth?
Necessary for growth
Regulates the synthesis of GH and GHRH-R
Excess can lead to growth inhibition (directly at the level of cartilage and bone synthesis) and a catabolic state
What pathway acts downstream of the GH receptor which ultimately leads to activation of transcription factors?
Jak/Stat pathway
Describe the mechanism of how the hypothalmus can stimulate the somatotroph leading to increased IGF-1
What are some of the diabetogenic effects of GH?
Name the three sites of action of GH and its effects on those sites.
Name the three sites of action of IGF1 and its effects on those sites.