I used to avoid your videos because they were kinda long. But you really explain things well and I wind up saving time because I don't have to replay the video a million times or hunt down another explanation. For whats it worth, thanks. And keep up the good work!
When in a fasted state what controls glucagon to limit over production of Blood Glucose? Insulin? For instance when I fast my BG levels run steady at 120-130. Is this the simply the result of high glucagon and low insulin ratio? I produce either too much glucagon or too little insulin?
Can u please please please move away from the board at the end of the section so we can screenshot that's my only thing other than that ur perfect thanx a bunch
+Adam Johnston ... Where does he state that PP1 is bound to phosphorylase-a? Are you thinking of the liver? I think the diagram he has drawn is representative of PP1 in the muscle... In which case it is only bound to the regulatory subunit (not phosphorylase-a).
+Adam Johnston Thank you. I appreciate your thoughtful responses. In that lecture "insulin and glucose regulation of glycogenesis" he talks specifically about liver cells. Glycogen degradation is regulated differently in the muscle and liver. I understand the way in which it is regulated in the liver, I'm just a tad unclear on how it is in it's active form in the muscle. But, I'm guessing that if glucose levels are high, glycogen degradation will be inhibited because glucagon and epinephrine signals won't be released. So PKA won't be activated, putting a complete halt on the entire signal cascade... Therefore, PKA won't be able to simultaneously deactivate PP1 either, allowing it to dephosphorylate glycogen synthase b to glycogen synthase a.
+Adam Johnston That's okay :) Thank you! I think was/am also confused about what you meant by PKA and phosphorylase binding directly to the active site of PP1, as to my understanding (and my notes! Haha) PP1 is always bound to a regulatory subunit and is always indirectly inhibited in both the muscle and liver. In the muscle, PP1 inhibited by the activated inhibitory molecule. In the liver, it's a different story, lol. That's when phosphorylase gets involved. Phosphorylase and PP1 are both bound to the regulatory subunit in the liver. If glucose levels are low in the liver, PP1 stays bound to the regulatory subunit and therefore, remains inactive. For PP1 to be active in the liver, glucose levels are high in the cell, triggering the pathway I believe you're thinking about. As far as I know, phosphorylase is not involved in the regulation of PP1 in the muscle. Only PKA (as he has drawn in this video), which indirectly inactivates PP1 by activating an inhibitor to do the dirty work, lol. Biochemistry can throw you for a loop sometimes.
i think it's always activated because we always need to store glycogen But when a special incident occurs like(heavy training or fasting) PP1 is deactivated and we break down glycogen to produce glucose
