Amino acid concentrations and protein metabolism of two types of rat skeletal muscle in postprandial state and after brief starvation

Title:

Amino acid concentrations and protein metabolism of two types of rat skeletal muscle in postprandial state and after brief starvation

Creator:

Holeček, M. and Mičuda, S.

Identifier:

https://cdk.lib.cas.cz/client/handle/uuid:91048296-f629-46be-9e52-4b276f8116ab
uuid:91048296-f629-46be-9e52-4b276f8116ab

Subject:

red and white muscle, amino acids, starvation, atrogens, and branched-chain amino acids

Type:

article, model:article, and TEXT

Description:

We have investigated amino acid concentrations and protein metabolism in musculus extensor digitorum longus (EDL, fasttwitch, white muscle) and musculus soleus (SOL, slow-twitch, red muscle) of rats sacrificed in the fed state or after one day of starvation. Fractional protein synthesis rates (FRPS) were measured using the flooding dose method (L-[3,4,5-3H]phenylalanine). Activities of two major proteolytic systems in muscle (the ubiquitin-proteasome and lysosomal) were examined by measurement of chymotrypsin like activity of proteasome (CTLA), expression of ubiquitin ligases atrogin-1 and muscle-ring-finger-1 (MuRF-1), and cathepsin B and L activities. Intramuscular concentrations of the most of non-essential amino acids, FRPS, CTLA and cathepsin B and L activities were in postprandial state higher in SOL when compared with EDL. The differences in atrogin-1 and MuRF-1 expression were insignificant. Starvation decreased concentrations of a number of amino acids and increased concentrations of valine, leucine, and isoleucine in blood plasma. Starvation also decreased intramuscular concentrations of a number of amino acids differently in EDL and SOL, decreased protein synthesis (by 31 % in SOL and 47 % in EDL), and increased expression of atrogin-1 and MuRF-1 in EDL. The effect of starvation on CTLA and cathepsin B and L activities was insignificant. It is concluded that slow-twitch (red) muscles have higher rates of protein turnover and may adapt better to brief starvation when compared to fast-twitch (white) muscles. This phenomenon may play a role in more pronounced atrophy of white muscles in aging and muscle wasting disorders.

Language:

English

Rights:

http://creativecommons.org/publicdomain/mark/1.0/
policy:public

Source:

Physiological research | 2017 Volume:66 | Number:6

Harvested from:

CDK

Metadata only:

false