Effect of leucine metabolite beta-hydroxy-beta-methylbutyrate on muscle metabolism during resistance-exercise training.
The effects of dietary supplementation with the leucine metabolite beta-hydroxy-beta-methylbutyrate (HMB) were studied in two experiments. In study 1, subjects (n = 41) were randomized among three levels of HMB supplementation (0, 1.5 or 3.0 g HMB/day) and two protein levels (normal, 117 g/day, or high, 175 g/day) and weight lifted for 1.5 h 3 days/wk for 3 wk. In study 2, subjects (n = 28) were fed either 0 or 3.0 g HMB/day and weight lifted for 2-3 h 6 days/wk for 7 wk. In study 1, HMB significantly decreased the exercise-induced rise in muscle proteolysis as measured by urine 3-methylhistidine during the first 2 wk of exercise (linear decrease, P < 0.04). Plasma creatine phosphokinase was also decreased with HMB supplementation (week 3, linear decrease, P < 0.05). Weight lifted was increased by HMB supplementation when compared with the unsupplemented subjects during each week of the study (linear increase, P < 0.02). In study 2, fat-free mass was significantly increased in HMB-supplemented subjects compared with the unsupplemented group at 2 and 4-6 wk of the study (P < 0.05). In conclusion, supplementation with either 1.5 or 3 g HMB/day can partly prevent exercise-induced proteolysis and/or muscle damage and result in larger gains in muscle function associated with resistance training.
http://www.ncbi.nlm.nih.gov/pubmed/8941534
suplementacja HMB w dawce 1,5-3g hamuje proteolize (katabolzim miesni)
Wniosek - dziala antykatabolicznie!
SUUUUUUUPER!
..........ale chwile małą chwilę:
antykatabolicznie to mało napisane - antyanabolicznie zarazem!
Stwierdzenie producentów ze hmb działa jako antykatabolik - jest po części słuszne - tylko trzeba dopisac druga część - że działa tez 'blokując' szybkość syntezy!
Wplywa na caly metabolizm bialek - zarowno degradacje jak i synteze!
Effect of beta-hydroxy-beta-methylbutyrate (HMB) on protein metabolism in whole body and in selected tissues.
Beta-hydroxy-beta-methylbutyrate (HMB) is a leucine metabolite with protein anabolic effect. The aim of the study was to examine the role of exogenous HMB on leucine and protein metabolism in whole body and selected tissues. Rats were administered by HMB (0.1 g/kg b.w.) or by saline. The parameters of whole-body protein metabolism were evaluated 24 h later using L-[1-14C]leucine and L-[3,4,5-3H]phenylalanine. Changes in proteasome dependent proteolysis and protein synthesis were determined according the "chymotrypsin-like" enzyme activity and labeled leucine and phenylalanine incorporation into the protein. A decrease in leucine clearance and whole-body protein turnover (i.e., a decrease in whole-body proteolysis and protein synthesis) was observed in HMB treated rats. Proteasome-dependent proteolysis decreased significantly in skeletal muscle, changes in heart, liver, jejunum, colon, kidney, and spleen were insignificant. Decrease in protein synthesis was observed in the heart, colon, kidney, and spleen, while an increase was observed in the liver. There were no significant changes in leucine oxidation. We conclude that protein anabolic effect of HMB in skeletal muscle is related to inhibition of proteolysis in proteasome. Alterations in protein synthesis in visceral tissues may affect several important functions and the metabolic status of the whole body.
http://www.ncbi.nlm.nih.gov/pubmed/19056452
szczurom podano dawke 0.1g HMB/kgmc
po 24h zbadano wplyw hmb na metabolizm bialek
wyniki:
-hmb dziala hamujące na proteolize - spadlo o 17% w porownaniu do grupy placebo (czyli dobrze)
-ale rowniez hamująco na szybkosc syntezy
synteza (leucyny) spadla o 22% w porownaniu do grupy placebo (czyli juz nie tak dobrze!)
-wykorzystanie leucyny bylo o ~18% mniejsze w porownaniu do grupy placebo
-bez wiekszych zmian w utlenianiu leucyny
wnioski:
Głowna droga katabolizmu miesni jest spowodowana przez wieloenzymatyczny kompleks utworzony z proteaz (proteasom).
HMB hamuje dzialanie tego procesu - ale jednoczesnie hamuje szybkosc syntezy!
Mało powiedziane - hamuje bardziej synteze białek niz ich degradacje!
z matematyki nigdy nie bylem dobry - ale chyba w obliczeniach % sie nie pomylilem ?
Zmieniony przez - solaros w dniu 2011-05-25 04:20:11
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Wszystko jest trucizną i nic nie jest trucizną, tylko dawka czyni, że dana substancja nie jest trucizną!".
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