Improved high altitude hypoxic tolerance and amelioration of anorexia and hypophagia in rats on oral glutamate supplementation.
BACKGROUND
The objective of this study is to evaluate the efficacy of oral glutamic acid supplementation in promoting hypoxic tolerance.


METHODS
The experiments were conducted in albino rats by exposing them to three levels of hypoxia in a simulated environment for varying periods of time. The parameters studied include: gasping time at 35,000 ft (10,668 m), food and water intake, and heart to body weight (b.w.) ratio at 25,000 ft (7620 m), tolerance to composite stress at 15,000 ft (4572 m) and biodistribution of glutamate (glu).


RESULTS
Supplementation of Glu (27 mg x kg(-1) b.w.) as glutamic acid dissolved in normal saline resulted in 4.8 times enhanced hypoxic tolerance (time taken for appearance of first gasp), 23% body weight gain and 24% increase in food consumption over control during hypoxia. When animals were subjected to composite stress of cold, hypoxia and restraint (CHR), the Glu fed animals showed higher resistance to fall in rectal temperature than the control group. Hypoxia significantly enhanced heart to body weight ratio compared with control, and Glu supplementation reduced and brought it down to that of control.


CONCLUSIONS
The study reveals that Glu in optimal doses may be a conditionally essential amino acid resulting in enhanced tolerance to hypoxia and cold.
Kumar
D
D
Defence Institute of Physiology and Allied Sciences, Timarpur, Ministry of Defence, Delhi, India.
Bansal
A
A
Thomas
P
P
Mongia
S S
SS
Sharma
S K
SK
Sairam
M
M
Grover
S K
SK
Singh
M V
MV
Prasad
D
D
Ilavazhagan
G
G
Selvamurthy
W
W
D000284:Administration, Oral; D000532:Altitude Sickness / Q000150:complications / Q000378:metabolism / Q000517:prevention & control*; D000818:Animals; D000855:Anorexia / Q000209:etiology / Q000378:metabolism / Q000517:prevention & control*; D001835:Body Weight / Q000187:drug effects; D019587:Dietary Supplements; D004195:Disease Models, Animal; D004353:Drug Evaluation, Preclinical; D005247:Feeding Behavior / Q000187:drug effects*; D018698:Glutamic Acid / Q000493:pharmacokinetics / Q000627:therapeutic use*; D006801:Humans; D007035:Hypothermia / Q000209:etiology / Q000378:metabolism / Q000517:prevention & control*; D008297:Male; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D012119:Respiration / Q000187:drug effects*; D014018:Tissue Distribution
D018698:Glutamic Acid