Is there truly a need for daily creatine supplementation?
I say, no way.
I've posted an abstract of this study before, but I just found access to the entire study.
Here's a case study which indicated that daily creatine supplementation was not needed to maintain skeletal muscle PCr saturation during a 30-day washout.... yes, 30-days. The study was repeated twice.
What was even more impressive, was that PCr levels increased 45% after the first bout (20-g for 5-days), [B]and only 22% of that increase was lost out of a 30-day time-frame.... that's still 23% higher than the pre-supplementational values.[/B] This would suggest that daily creatine supplementation appears to only keep serum levels from being depleted.
If PCr levels remain elevated from creatine supplementation for a significant duration of time, even when not supplementing creatine.... then I strongly feel that creatine can easily be ingested on workout days only, without any depletion of skeletal muscle PCr whatsoever.
[url=http://www.pharmacy.unc.edu/pkpd/AMP%20Articles/Rawson%20et%20al%20JSCR%202004%20Case%20Study.pdf][b]EFFECTS OF REPEATED CREATINE SUPPLEMENTATION ON MUSCLE, PLASMA, AND URINE CREATINE LEVELS[/b][/url]
Tyrosine phosphorylation of the creatine transporter?
Here's a study on creatine transporter expression/downregulation in response to creatine supplementation in animals during sepsis. I wonder if tyrosine phosphorylation of the creatine transporter can be a factor in sepsis-free subjects?
"Thus, on the basis of the results presented in the current study and the data available in the literature, it is reasonable to hypothesize that extracellular Cr must be transported into the cells where accumulated Cr feedback inhibits c-Src-related tyrosine phosphorylation of the CreaT. Although the mechanism(s) by which the downregulatory effects on c-Src-related tyrosine phosphorylation of the CreaT after dietary Cr supplementation occur is unknown, we speculate that preaccumulation of intracellular Cr in muscle after oral Cr supplementation may cause acquired intrinsic alteration(s) in the control of myocellular energy metabolism that may trigger changes in intracellular signaling pathways by which the downregulatory effects on c-Src-related tyrosine phosphorylation of the CreaT after Cr supplementation occurs in skeletal muscle during sepsis. These remain to be defined and are the subjects of future investigations."
"Although the physiological relevance of Cr supplementation's downregulatory effects on tyrosine phosphorylation of the CreaT during sepsis is not yet clear, it is obvious that myocellular CreaT function is tightly regulated and involves c-Src-related tyrosine phosphorylation during sepsis."
[url]http://ajpendo.physiology.org/cgi/reprint/282/5/E1046.pdf?ck=nck[/url]