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NBME 18 Answers

nbme18/Block 3/Question#20 (10.5 difficulty score)
A 45-year-old man comes to the physician for ...
Transcription Factor c-Jun: increased; β-Myosin Heavy Chain: increased; Endothelin: increased🔍
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 +4 
submitted by azibird(158),

Endothelin (ET)-1, a potent vasoconstrictor peptide from vascular endothelial cells, is also synthesized and secreted by cardiomyocytes and induces hypertrophy of cardiomyocytes through activating phospholipase C, protein kinase C, extracellular signal-regulated kinase (ERK) 1 and ERK2, and upregulation of c-Fos and c-Jun.

https://www.ahajournals.org/doi/full/10.1161/01.CIR.0000112596.06954.00?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%3dpubmed

motherhen  is this super out of left field or am I supposed to know this +6  
ab721  @motherhen I don't know if this is correct, but I personally tried to reason this one out. If hypertrophy is occurring, more sarcomeres are added which means more beta-myosin. Hypertrophy also means the cell is doing more work, so a transcription factor is likely to be upregulated. From there, the only option with both of those increased had endothelin increased as well, though unclear why that's necessarily increased. +5  
motherhen  genius +1  
yerpderp  Loud S2 made me think of pulmonary hypertension which would have an incr endothelin +  
geekymle  that loud s2 was from systemic hypertension. +  
utap2001  systemic hypertension -> induce LV hypertrophy -> induce pulmonary hypertension -> endothelin increase, plus loud S2 and S4 gallop +