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- Blomstrand, Eva, et al.
(författare)
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Influence of ingesting a solution of branched-chain amino acids on plasma and muscle concentrations of amino acids during prolonged submaximal exercise.
- 1996
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Ingår i: Nutrition (Burbank, Los Angeles County, Calif.). - 0899-9007 .- 1873-1244. ; 12:7-8, s. 485-90
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Tidskriftsartikel (refereegranskat)abstract
- On two occasions, seven male endurance-trained cyclists performed sustained exhaustive exercise with reduced muscle glycogen stores. During exercise, the subjects were supplied in random order with an aqueous solution of branched-chain amino acids (BCAA) or flavored water (placebo). Ingestion of BCAA caused the concentration of these amino acids to increase by 135% in the plasma and by 57% in muscle tissue during exercise, whereas in the placebo trial there was no change or a slight decrease in the concentration in plasma and a decrease of 18% in the muscle. The plasma concentration of alanine increased by 48% during exercise when BCAA were ingested, and the increase in the muscle concentration of alanine during exercise was larger (70% versus 31% in the placebo trial), suggesting an increased rate of alanine production. Also, the plasma concentration of arginine increased by 14% during exercise when BCAA were ingested, whereas there was no change during exercise in the placebo trial. There was a smaller decrease in the muscle glutamate concentration during exercise in the BCAA trial (32% versus 47% in the placebo trial; p < 0.05), but, for the remaining amino acids, there was no difference between the BCAA and placebo trials. There was a significant decrease in the muscle glycogen concentration during exercise in the placebo trial, whereas only a small decrease was found in the BCAA trial (28 and 9 mmol/kg wet wt [p < 0.05] in the placebo and BCAA trial, respectively). This might indicate that an increased supply of BCAA has a sparing effect on muscle glycogen degradation during exercise.
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| 2. |
- Thulin, T, et al.
(författare)
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Neuropeptide Y and hypertension
- 1995
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Ingår i: Nutrition. - 1873-1244. ; 11:Suppl. 5, s. 495-497
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Tidskriftsartikel (refereegranskat)abstract
- Neuropeptide Y is a cotransmitter in the sympathetic nervous system with potent contractile effects on blood vessels. The plasma levels of neuropeptide Y-like immunoreactivity in patients with severe hypertension (> 120 mmHg) were increased compared with the levels in control subjects and were still elevated after long-term pharmacologic treatment of normotension. Neuropeptide Y stimulated DNA synthesis, total cell number, and total protein production in human vascular smooth muscle cells through a Y1-receptor. A Gi/G(o)-coupled second messenger mechanism seems to be involved, because pretreatment with pertussis toxin abolished the mitogenic effect. Neuropeptide Y potentiated the mitogenic effect of noradrenaline, and together with adenosine 5'-triphosphate, the sympathetic cotransmitters reached a mitogenic effect of approximately 20% of fetal calf serum. We have shown that neuropeptide Y, noradrenaline, and adenosine 5'-triphosphate, apart from their effects on vascular tone, are stimulators of vascular smooth muscle cell growth. The receptors that mediate the mitogenic effect have been examined. The circulating plasma levels are increased in patients with severe hypertension. These findings indicate that the sympathetic cotransmitter neuropeptide Y may be of importance in sympathetic vascular regulation and involved in pathophysiologic conditions.
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