Glycogen degradation QQQQQQQQ - sarim

[ArchivalUser]

The rate of glycogen degradation in skeletal muscles increases several hundred folds after the onset of contraction compared to the resting state.This finding reflects enzyme activation by which of the following substances?

A-ADP
B-cAMP
C-Lactate
D-Ca2+
E-Glucose -6-phosphate

plz explain ur pick...

[ArchivalUser]

d??

[ArchivalUser]

Ca++ is released from the sarcoplasmic reticulum during exercise, Ca++ activates phosphorylase kinase, which activates glycogen phosphorylase, which cause glycogen degradation

[ArchivalUser]

i think it is cAMP (FA pg112 2009)

[ArchivalUser]

From kaplan, glycogen phosphorylase is activated by both cAMP and Ca++, but here the question is asking during contraction, so I guess Ca++ is the answer.

[ArchivalUser]

i agree with the explanation by goforward and ans. is Ca++

[ArchivalUser]

i see. thank you, fexofenadine.

[ArchivalUser]

agree with goforward.

[ArchivalUser]

DDD

as goforward explained But Ca+2 "DIRECTLY" activate Glycogen myophosphorylase WITHOUT phospohrylating it as is the case with AMP (not cAMP) which get accumulated in extream anaerobic conditions.

Epinephrine(muscle & liver) and Glucagon(liver)----->G-protein--->increase cAMP------->+protein kinase-A----->Phosphrylate the Glycogen phosphorylase rendering it active.

source: USMLE world