Kreatin-Dauersupplementation
hallo klaus,
danke für di info, sie war mir schon bekannt. hier ist der abstract des papers (problemlos in medline abzurufen)
die studie wurde an ratten durchgeführt und ist nicht automatisch auf den menschen übertragbar.
obwohl es untersuchungen gibt, die keine nachteiligen effekte bei kreatin-dauersupplementation zeigen (z.b. bei der deutschen rudernationalmannschaft, erhaltungsdosis 2g/d), würde ich nicht dafür plädieren.
im bodybuilding kommen eh nur die (geringgradigen) auswirkungen auf die optik zum tragen und spielt kreatin keine grosse rolle. im leistungssport sollte man meiner meinung nach auch die kreatinsupplementation periodisieren.
die kraftausdauer der deutschen ruderer ist jedenfalls beachtlich: beim bankziehen 60 x 60kg! (wenn's stimmt)
gruss, kurt
1: Mol Cell Biochem 1998 Jul;184(1-2):427-437
Creatine supplementation in health and disease. Effects of chronic creatine
ingestion in vivo: down-regulation of the expression of creatine transporter
isoforms in skeletal muscle.
Guerrero-Ontiveros ML, Wallimann T.
Institute for Cell Biology, Swiss Federal Institute of Technology,
ETH-Honggerberg, Zurich.
Interest in creatine (Cr) as a nutritional supplement and ergogenic aid for
athletes has surged over recent years. After cellular uptake, Cr is
phosphorylated to phosphocreatine (PCr) by the creatine kinase (CK) reaction
using ATP. At subcellular sites with high energy requirements, e.g. at the
myofibrillar apparatus during muscle contraction, CK catalyzes the
transphosphorylation of PCr to ADP to regenerate ATP, thus preventing a
depletion of ATP levels. PCr is thus available as an immediate energy source,
serving not only as an energy buffer but also as an energy transport vehicle.
Ingestion of creatine increases intramuscular Cr, as well as PCr concentrations,
and leads to exercise enhancement, especially in sprint performance. Additional
benefits of Cr supplementation have also been noticed for high-intensity
long-endurance tasks, e.g. shortening of recovery periods after physical
exercise. The present article summarizes recent findings on the influence of Cr
supplementation on energy metabolism, and introduces the Cr transporter protein
(CreaT), responsible for uptake of Cr into cells, as one of the key-players for
the multi-faceted regulation of cellular Cr homeostasis. Furthermore, it is
suggested that patients with disturbances in Cr metabolism or with different
neuro-muscular diseases may benefit from Cr supplementation as an adjuvant
therapy to relieve or delay the onset of symptoms. Although it is still unclear
how Cr biosynthesis and transport are regulated in health and disease, so far
there are no reports of harmful side effects of Cr loading in humans. However,
in this study, we report that chronic Cr supplementation in rats down-regulates
in vivo the expression of the CreaT. In addition, we describe the presence of
CreaT isoforms most likely generated by alternative splicing.
PMID: 9746337 [PubMed - indexed for MEDLINE]