Effect of Germfree Status, Lactation and Fasting Time on Plasma Amino Acids of C3H Mice

• Published in: The Journal of nutrition Vol. 109; no. 1; pp. 70 - 76
• Main Authors: Pleasants, Julian R., Reddy, Bandaru S., Hessling, Janice Johnson, Reyniers, Jon P., Wostmann, Bernard S.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.01.1979
• Subjects: Amino Acids - blood; Animals; Diet; Fasting; Female; Germ-Free Life; germfree mice; Lactation; Male; Mice; Mice, Inbred C3H; plasma amino acids; Pregnancy; Sex Factors; Time Factors; germfree mice; plasma amino acids; mice; lactation
• ISSN: 0022-3166; 1541-6100
• DOI: 10.1093/jn/109.1.70

Plasma free amino acid (PAA) concentrations were compared in germfree and conventional C3H/He adult mice of both sexes fasted 4 hours, and in lactating conventional mice after 2, 4, 6, and 8 hours of fasting. All were fed an autoclaved diet of proven adequacy for reproduction which contained 23.7% protein derived from grains and soy bean meal. Amino acid concentrations in deproteinized heart blood plasma were determined by standard column chromatography. Germfree and conventional mice showed no conspicuous differences in any PAA concentrations. Lysine was 40 to 50% higher in female than in male mice of either microbial status. The PAA of lactating conventional mice (12th to 18th day of lactation) reached a plateau at the 4 and 6 hour fasting periods, with the essential amino acids generally higher than in non-lactating mice fasted 4 hours. The increase over non-lactating mice at that time period was statistically significant for arginine, isoleucine, lysine, phenylalanine, tyrosine, urea, and citrulline. Most PAA in the lactating mice had declined from their plateau concentrations when determined after 8 hours of fasting. It is concluded that microbial status as such does not appreciably change the essential amino acid concentrations in the blood and that PAA concentrations after a 4 hour fast provide a reproducible pattern for both lactating and non-lactating mice.