mTORC1 Rebound Effect:
So many things are a double-edged sword: There is opposition and rebuttal in all papers published. There is no guarantee that anything we read is true.:
The rebound effect isn’t all bad mTORC1 activation may help with muscle hypertrophy.
And why I am now much more interested in peak values than AUC in taking rapamycin.
“Even though there is more to muscle growth than activating mTOR, coaches and athletes should be trying to increase mTOR activity as much as possible.”
“If humans are given the immunosuppressant rapamycin (blocks mTOR) before they perform their strength training, there is no increase in protein synthesis (Drummond et al., 2009). This demonstrates that mTOR is required for the increase in muscle protein synthesis after resistance exercise.”
“Skeletal muscle hypertrophy largely depends on protein turnover, defined as balance between protein synthesis and degradation. Activation of mTOR signaling positively affects processes of protein transcription and translation, and inhibits autophagy, leading to increase in size of muscle fibers.”
“However, in adult mammals, resting mTORC1 activity is reduced and does not appear to be necessary for the maintenance of muscle mass since the suppression of resting mTORC1 activity in adult muscle by rapamycin or raptor deletion does not induce muscle loss but does cause a slight reduction in basal protein synthesis.”
However the same paper bottom line:
“Although activation of mTORC1 may not be required for the maintenance of muscle mass in adult animals, it does appear to be a critical pathway for the induction of adaptive muscle growth, especially in response to mechanical overload.”
“mTOR signaling pathway and mTOR inhibitors in cancer: progress and challenges”
“Autophagy and apoptosis of cancer
On the one hand, autophagy can keep the genome stable by removing damaged organelles and misfolded proteins, so it can inhibit the growth of cancerous cells [46]. On the other hand, autophagy provides the tumor with more nutrients, which strengthens the tumor’s ability to cope with extreme environments [47, 48]. In addition, the unlimited proliferation of tumors is partly due to the inhibition of tumor cell apoptosis.”
https://www.gssiweb.org/docs/default-source/sse-docs/sse123_baar_sse_bleed.pdf?sfvrsn=2
mTOR signaling pathway and mTOR inhibitors in cancer: progress and challenges | Cell & Bioscience | Full Text integrates%20 signals%20from%20 multiple,proliferation%20and%20survival%20%5B1%5D.
https://www.sciencedirect.com/science/article/abs/pii/B9780123964540000229#:~:text=Skeletal%20 muscle%20 hypertrophy%20 largely%20 depends on%20size%20of%20 muscle%20 fibers.
