I was wondering if anyone looked at AMPK activation (phosphorylation of T172) in-vivo in skeletal muscle or heart after overnight fasting. I would expect it would be activated, but I could not find any evidence in the literature.
Any advice would be greatly appreciated.
I give you first a rapid answer. You have to keep in mind that metabolism is under the control of the clock genes system. So, metabolism during night is different from that in diurnal phase.
I doubt it because I don't think the glycogen in skeletal muscle is depleted during sleep unless. The liver glycogen store supplies glucose to the circulation. However, muscle doesn't have the glucose-6-phosphatase that would be required for glycogen to be converted to glucose and leave the cell. In other words the glycogen stored in your muscles is only depleted when your muscles need the energy. If you went running your muscle AMP kinase will become activated, but I'm doubting that an overnight fast would do it.
During night that is a resting phase for muscle cells, the energy stores have to be restored from the nutrients supply during evening. So, the AMPK and catabolic pathways should be down regulated. The low cardiac activity maintained during sleeping period do not correspond for an acute energy demand. So, I agree with you : AMPK is probably not activated during night that is conversely characterized by anabolic process. (sorry for my english that is niot very fluent...)
Valérie
- Badges
- Science topic