PMID- 29435722
OWN - NLM
STAT- MEDLINE
DCOM- 20190130
LR  - 20211204
IS  - 1438-2199 (Electronic)
IS  - 0939-4451 (Linking)
VI  - 50
IP  - 5
DP  - 2018 May
TI  - L-Arginine regulates protein turnover in porcine mammary epithelial cells to 
      enhance milk protein synthesis.
PG  - 621-628
LID - 10.1007/s00726-018-2541-7 [doi]
AB  - Milk is an important food for mammalian neonates, but its insufficient production 
      is a nutritional problem for humans and other animals. Recent studies indicate 
      that dietary supplementation with L-arginine (Arg) increases milk production in 
      mammals, including sows, rabbits, and cows. However, the underlying molecular 
      mechanisms remain largely unknown. The present study was conducted with porcine 
      mammary epithelial cells (PMECs) to test the hypothesis that Arg enhances milk 
      protein synthesis via activation of the mechanistic target of rapamycin (mTOR) 
      cell signaling. PMECs were cultured for 4 days in Arg-free basal medium 
      supplemented with 10, 50, 200, or 500 mumol/L Arg. Rates of protein synthesis and 
      degradation in cells were determined with the use of 
      L-[ring-2,4-(3)H]phenylalanine. Cell medium was analyzed for beta-casein and 
      alpha-lactalbumin, whereas cells were used for quantifying total and phosphorylated 
      levels of mTOR, ribosomal protein S6 kinase (p70S6K), 4E-binding protein 1 
      (4EBP1), ubiquitin, and proteasome. Addition of 50-500 mumol/L Arg to culture 
      medium increased (P < 0.05) the proliferation of PMECs and the synthesis of 
      proteins (including beta-casein and alpha-lactalbumin), while reducing the rates of 
      proteolysis, in a dose-dependent manner. The phosphorylated levels of mTOR, 
      p70S6K and 4EBP1 were elevated (P < 0.05), but the abundances of ubiquitin and 
      proteasome were lower (P < 0.05), in PMECs supplemented with 200-500 mumol/L Arg, 
      compared with 10-50 mumol/L Arg. These results provide a biochemical basis for the 
      use of Arg to enhance milk production by sows and have important implications for 
      improving lactation in other mammals (including humans and cows).
FAU - Ma, Qingquan
AU  - Ma Q
AD  - Institute of Animal Nutrition, Northeast Agricultural University, Harbin, 150030, 
      China.
AD  - Department of Animal Science, Texas A&M University, Room 212 Kleberg Blvd, 2471 
      TAMU, College Station, TX, 77843, USA.
FAU - Hu, Shengdi
AU  - Hu S
AD  - Department of Animal Science, Texas A&M University, Room 212 Kleberg Blvd, 2471 
      TAMU, College Station, TX, 77843, USA.
FAU - Bannai, Makoto
AU  - Bannai M
AD  - AminoScience Division, Department of Business Strategy and Planning, Ajinomoto 
      Co., Inc., Tokyo, Japan.
FAU - Wu, Guoyao
AU  - Wu G
AD  - Department of Animal Science, Texas A&M University, Room 212 Kleberg Blvd, 2471 
      TAMU, College Station, TX, 77843, USA. g-wu@tamu.edu.
LA  - eng
GR  - 2014-67015-21770/USDA National Institute of Food and Agriculture/International
GR  - H-8200/Texas A&amp;M AgriLife Research/International
PT  - Journal Article
PT  - Research Support, U.S. Gov't, Non-P.H.S.
DEP - 20180212
PL  - Austria
TA  - Amino Acids
JT  - Amino acids
JID - 9200312
RN  - 0 (Carrier Proteins)
RN  - 0 (Milk Proteins)
RN  - 0 (Ubiquitin)
RN  - 94ZLA3W45F (Arginine)
RN  - EC 2.7.11.1 (Ribosomal Protein S6 Kinases, 70-kDa)
RN  - EC 2.7.11.1 (TOR Serine-Threonine Kinases)
RN  - EC 3.4.25.1 (Proteasome Endopeptidase Complex)
SB  - IM
MH  - Animals
MH  - Arginine/*pharmacology
MH  - Carrier Proteins/metabolism
MH  - Cells, Cultured
MH  - Female
MH  - Mammary Glands, Animal/cytology/*metabolism
MH  - Milk Proteins/*biosynthesis
MH  - Proteasome Endopeptidase Complex/metabolism
MH  - Protein Biosynthesis/*drug effects
MH  - Proteolysis/drug effects
MH  - Ribosomal Protein S6 Kinases, 70-kDa/metabolism
MH  - Swine
MH  - TOR Serine-Threonine Kinases/metabolism
MH  - Ubiquitin/metabolism
OTO - NOTNLM
OT  - Arginine
OT  - Mammary gland
OT  - Milk protein
OT  - mTOR signaling
EDAT- 2018/02/13 06:00
MHDA- 2019/01/31 06:00
CRDT- 2018/02/14 06:00
PHST- 2017/11/27 00:00 [received]
PHST- 2018/01/29 00:00 [accepted]
PHST- 2018/02/13 06:00 [pubmed]
PHST- 2019/01/31 06:00 [medline]
PHST- 2018/02/14 06:00 [entrez]
AID - 10.1007/s00726-018-2541-7 [pii]
AID - 10.1007/s00726-018-2541-7 [doi]
PST - ppublish
SO  - Amino Acids. 2018 May;50(5):621-628. doi: 10.1007/s00726-018-2541-7. Epub 2018 
      Feb 12.