Dataset Information

The effects of potassium ions and denervation on protein synthesis and the transport of amino acids in muscle.

ABSTRACT: 1. The effects of varying concentrations of K(+) during incubation, of denervation and of various drugs on the accumulation of (14)C-labelled amino acids, their incorporation into protein and the stimulation of these processes by insulin in rat diaphragm preparations were studied. 2. The accumulation of glycine and aminoisobutyrate and incorporation of glycine into protein was less in tissue incubated in K(+)-free buffer or 20mm-K(+) than with 5-10mm-K(+). Incorporation of leucine was unaffected. 3. Incorporation into protein of amino acids by diaphragm that had been denervated 3 days previously was elevated. Accumulation of both glycine and aminoisobutyrate was also raised but that of phenylalanine was unaffected. 4. Accumulation of glycine by diaphragm and extensor digitorum longus muscle was decreased by a number of agents including cocaine and mepyramine. 5. The stimulation of incorporation by insulin was unaffected by changes in K(+) or in the presence of cocaine and mepyramine. Denervated tissue was markedly less responsive to insulin than its control. 6. The results are discussed in the context of the relation of amino acid accumulation to operation of the Na(+) pump and the influence of insulin thereon.

SUBMITTER: Harris EJ

PROVIDER: S-EPMC1270074 | biostudies-other | 1966 Oct

REPOSITORIES: biostudies-other

ACCESS DATA

Similar Datasets

Project description:BACKGROUND:A previous clinical study reported that the addition of an amylopectin/chromium complex (ACr; Velositol®) to 6?g of whey protein (WP) significantly enhanced muscle protein synthesis (MPS). Branched-chain amino acids (BCAAs) are also well-known to enhance MPS. The aim of this study was to determine if the addition of ACr to BCAAs can enhance MPS and activate expression of the mammalian target of the rapamycin (mTOR) pathway compared to BCAAs and exercise alone in exercise-trained rats. METHODS:Twenty-four male Wistar rats were randomly divided into three groups (n?=?8 per group): (I) Exercise control, (II) Exercise plus BCAAs (0.465?g/kg BW, a 6?g human equivalent dose (HED)), and (III) Exercise plus BCAAs (0.465?g/kg BW) and ACr (0.155?g/kg BW, a 2?g HED). All animals were trained with treadmill exercise for 10?days. On the day of the single-dose experiment, rats were exercised at 26?m/min for 2?h and then fed, via oral gavage, study product. One hour after the consumption of study product, rats were injected with a bolus dose (250?mg/kg BW, 25?g/L) of phenylalanine labeled with deuterium to measure the fractional rate of protein synthesis (FSR). Ten minutes later, muscle tissue samples were taken to determine MPS measured by FSR and the phosphorylation of proteins involved in the mTOR pathway including mTOR, S6K1, and 4E-BP1. RESULTS:ACr combined with BCAAs increased MPS by 71% compared to the exercise control group, while BCAAs alone increased MPS by 57% over control (p?<?0.05). ACr plus BCAAs significantly enhanced phosphorylation of mTOR, S6K1 and 4E-BP1 compared to exercise control rats (p?<?0.05). The addition of ACr to BCAAs enhanced insulin levels, mTOR and S6K1 phosphorylation compared to BCAAs alone (p?<?0.05). Serum insulin concentration was positively correlated with the levels of mTOR, (r?=?0.923), S6K1 (r?=?0.814) and 4E-BP1 (r?=?0.953). CONCLUSIONS:In conclusion, the results of this study provide evidence that the addition of ACr to BCAAs significantly enhances exercise-induced MPS, and the phosphorylation of mTOR signaling proteins, compared to BCAAs and exercise alone.

Dataset Information

The effects of potassium ions and denervation on protein synthesis and the transport of amino acids in muscle.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure