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Postnatal changes of skeletal muscle...

Yang, Xiaojian.

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Postnatal changes of skeletal muscle protein synthesis in the pig.

Record Type:	Language materials, printed : Monograph/item
Title/Author:	Postnatal changes of skeletal muscle protein synthesis in the pig./
Author:	Yang, Xiaojian.
Description:	278 p.
Notes:	Source: Dissertation Abstracts International, Volume: 71-01, Section: B, page: 0005.
Contained By:	Dissertation Abstracts International71-01B.
Subject:	Agriculture, Animal Culture and Nutrition. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=NR55230
ISBN:	9780494552308

Postnatal changes of skeletal muscle protein synthesis in the pig.
Yang, Xiaojian.

Postnatal changes of skeletal muscle protein synthesis in the pig. - 278 p.

Source: Dissertation Abstracts International, Volume: 71-01, Section: B, page: 0005.

Thesis (Ph.D.)--University of Guelph (Canada), 2009.

This thesis is an investigation of postnatal changes of protein synthetic activities in the skeletal muscle of neonatal pigs. Methodological aspects of measuring fractional protein synthesis in vivo by an intraperitoneal (ip) injection of a flooding dose of phenylalanine (Phe) containing L-[ring-2H5] Phe were investigated. The results suggest that collecting samples within 30 min after the tracer injection would help reduce the potential effect of cortisol surge associated with the ip tracer injection. This validated flooding dose technique was then employed to study postnatal changes of protein synthetic activities in the skeletal muscle of neonatal pigs under fed conditions. Artificial neural network analysis was used to investigate the nature and relative importance of developmental changes of hormonal factors, including growth hormone, insulin, insulin-like growth factor I (IGF-I), and cortisol, as well as extracellular serum free amino acids to the regulation of postnatal changes of skeletal muscle protein synthesis via the mammalian target of rapamycin (mTOR)-dependent and mTOR-independent pathways. Thirty-six gilts were divided into suckling groups at ages of day 1, 4, 6, 12, 20, and one week post-weaning group at day 28, respectively. Fractional protein synthesis rate (Ks) and protein synthetic capacity (Cs) decreased with age, whereas protein synthetic efficiency (Ke) increased during the suckling period and then declined during the weaning transition. Generally speaking, protein abundances of protein translational initiation and elongation factors, and components in the mTOR-signaling pathway declined with age. Our data suggest that: (1) Cs was more important than Ke for the regulation of Ks in the skeletal muscle during the postnatal development; (2) insulin and IGF-I predominated over growth hormone and cortisol for the modulation of Ks, while insulin was most important for the phosphorylation of mTOR; (3) IGF-I predominated over the other three hormonal factors in the regulation of Ke, whereas the four hormonal factors contribute similarly to the regulation of Cs; (4) phosphorylated alpha-subunit of eukaryotic initiation factor 2 and total ribosomal protein S6 kinase 1 in the skeletal muscle were the two most important contributors for the regulation of Ke ; (5) total concentration of extracellular serum free essential amino acids was associated more closely with Ks than total concentration of extracellular free nonessential amino acids, although they contributed similarly to the phosphorylation of mTOR; and (6) the nature and magnitude of individual extracellular free amino acids in the regulation of the postnatal muscle protein synthesis were differential and yet collective but not predominant. In summary, protein synthesis decreases in the skeletal muscle of piglets postnatally, and the decline is, in part, due to the developmental changes of circulating hormonal factors and free amino acids.

ISBN: 9780494552308Subjects--Topical Terms:

1017857
Agriculture, Animal Culture and Nutrition.

Postnatal changes of skeletal muscle protein synthesis in the pig.
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020 $a 9780494552308
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100 1 $a Yang, Xiaojian. $3 1676809
245 1 0 $a Postnatal changes of skeletal muscle protein synthesis in the pig.
300 $a 278 p.
500 $a Source: Dissertation Abstracts International, Volume: 71-01, Section: B, page: 0005.
502 $a Thesis (Ph.D.)--University of Guelph (Canada), 2009.
520 $a This thesis is an investigation of postnatal changes of protein synthetic activities in the skeletal muscle of neonatal pigs. Methodological aspects of measuring fractional protein synthesis in vivo by an intraperitoneal (ip) injection of a flooding dose of phenylalanine (Phe) containing L-[ring-2H5] Phe were investigated. The results suggest that collecting samples within 30 min after the tracer injection would help reduce the potential effect of cortisol surge associated with the ip tracer injection. This validated flooding dose technique was then employed to study postnatal changes of protein synthetic activities in the skeletal muscle of neonatal pigs under fed conditions. Artificial neural network analysis was used to investigate the nature and relative importance of developmental changes of hormonal factors, including growth hormone, insulin, insulin-like growth factor I (IGF-I), and cortisol, as well as extracellular serum free amino acids to the regulation of postnatal changes of skeletal muscle protein synthesis via the mammalian target of rapamycin (mTOR)-dependent and mTOR-independent pathways. Thirty-six gilts were divided into suckling groups at ages of day 1, 4, 6, 12, 20, and one week post-weaning group at day 28, respectively. Fractional protein synthesis rate (Ks) and protein synthetic capacity (Cs) decreased with age, whereas protein synthetic efficiency (Ke) increased during the suckling period and then declined during the weaning transition. Generally speaking, protein abundances of protein translational initiation and elongation factors, and components in the mTOR-signaling pathway declined with age. Our data suggest that: (1) Cs was more important than Ke for the regulation of Ks in the skeletal muscle during the postnatal development; (2) insulin and IGF-I predominated over growth hormone and cortisol for the modulation of Ks, while insulin was most important for the phosphorylation of mTOR; (3) IGF-I predominated over the other three hormonal factors in the regulation of Ke, whereas the four hormonal factors contribute similarly to the regulation of Cs; (4) phosphorylated alpha-subunit of eukaryotic initiation factor 2 and total ribosomal protein S6 kinase 1 in the skeletal muscle were the two most important contributors for the regulation of Ke ; (5) total concentration of extracellular serum free essential amino acids was associated more closely with Ks than total concentration of extracellular free nonessential amino acids, although they contributed similarly to the phosphorylation of mTOR; and (6) the nature and magnitude of individual extracellular free amino acids in the regulation of the postnatal muscle protein synthesis were differential and yet collective but not predominant. In summary, protein synthesis decreases in the skeletal muscle of piglets postnatally, and the decline is, in part, due to the developmental changes of circulating hormonal factors and free amino acids.
590 $a School code: 0081.
650 4 $a Agriculture, Animal Culture and Nutrition. $3 1017857
650 4 $a Biology, Physiology. $3 1017816
690 $a 0475
690 $a 0719
710 2 $a University of Guelph (Canada). $3 1018650
773 0 $t Dissertation Abstracts International $g 71-01B.
790 $a 0081
791 $a Ph.D.
792 $a 2009
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=NR55230