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| Question | Answer |
| All derivatives of POMC | ACTH, b-MSH, a-MSH, b-lipotropin, y-lipotropin, b-endorphin, CLIP, enkaphhalin |
| What are the other classes of endogenous opiods other than those derived from POMC | Prenkephalin – source of several enkaphalins Prodynorphin – source of dynorphins |
| Explain POMC expression in anterior pituitary | In anterior placenta, POMC is preferentially cleaved to ACTH and b-liotropin (B-LPH). It is induced by stress and under control of CRH and is influenced by the feedback of glucocorticoids |
| Explain POMC expression in hypothalamus | POMC in hypothalamus is preferentially cleaved to a-MSH and b-endorphin. It is influenced by sex steroids. |
| Explain POMC secretion in placenta. | In placenta, POMC processing mostly yields a-MSH and b-endorphin (just like in hypothalamus) |
| Is CRH secreted by pregnancy tissues? | Yes - CRH is expressed by placenta, fetal membranes and decidua. CRH is 1000x serum level in pregnany. However, ACTH does not rise concordantly. This may be d/t CRH binding protein or CRH down-regulating it's own receptor in the pituitary in pregnant women. |
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