The Absorption by Immature and Adult Rats of Amino Acids from Raw and Autoclaved Fresh Pork

Wheeler, Priscilla; Morgan, Agnes Fay

doi:10.1093/jn/64.1.137

Cited by 41 publications

(13 citation statements)

References 9 publications

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“…It is recognized that this technique determines total splanchnic exchange and does not permit identification of the relative contributions of hepatic and nonhepatic tissues to the observed arterio-hepatic venous differences. However, studies in fasted animals have demonstrated portal vein alanine levels (26) in the same range as in arterial plasma (27) and an equivalence of essential amino acid concentrations in portal and radial venous blood (28,29). Thus it is unlikely that the splanchnic uptake of alanine noted in the present study is due to extrahepatic extraction or that significant amounts of alanine are released by the tissues drained by the portal vein in postabsorptive or fasted subjects.…”

Section: Discussionmentioning

confidence: 99%

Amino acid metabolism during prolonged starvation

Felig¹,

Owen²,

Wahren³

et al. 1969

J. Clin. Invest.

669

266

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A B S T R A C T Plasma concentration, splanchnic and renal exchange, and urinary excretion of 20 amino acids were studied in obese subjects during prolonged (5-6 wk) starvation. Splanchnic amino acid uptake was also investigated in postabsorptive and briefly (36)(37)(38)(39)(40)(41)(42)(43)(44)(45)(46)(47)(48) hr) fasted subjects.A transient increase in plasma valine, leucine, isoleucine, methionine, and a-aminobutyrate was noted during the 1st wk of starvation. A delayed, progressive increase in glycine, threonine, and serine occurred after the 1st 5 days. 13 of the amino acids ultimately decreased in starvation, but the magnitude of this diminution was greatest for alanine which decreased most rapidly during the 1st week of fasting.In all subjects alanine was extracted by the splanchnic circulation to a greater extent than all other amino acids combined. Brief fasting resulted in an increased arteriohepatic venous difference for alanine due to increased fractional extraction. After 5-6 wk of starvation, a marked falloff in splanchnic alanine uptake was attributable to the decreased arterial concentration. Prolonged fasting resulted in increased glycine utilization by the kidney and in net renal uptake of alanine.It is concluded that the marked decrease in plasma alanine is due to augmented and preferential splanchnic utilization of this amino acid in early starvation resulting in substrate depletion. Maintenance of the hypoalaninemia ultimately serves to diminish splanchnic uptake of this key glycogenic amino acid and is thus an important component of the regulatory mechanism whereby hepatic gluconeogenesis is diminished and protein catabolism is minimized in prolonged fasting. The altered renal ex-A preliminary report of part of this work has appeared in abstract form (1).Dr. Felig is recipient of U. S. Public Health Service Special Postdoctoral Fellowship, 5-F3-AM-36-069.

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Section: Discussionmentioning

confidence: 99%

Amino acid metabolism during prolonged starvation

Felig¹,

Owen²,

Wahren³

et al. 1969

J. Clin. Invest.

669

266

View full text Add to dashboard Cite

show abstract

“…This was attributed to the rate of protein digestion. Wheeler and Morgan (1958) made similar observations in studies with rats. Goldberg and Guggenheim (1962) reported much higher amino acid levels in the portal blood of rats fed casein as compared to those fed lactalbumin* again suggesting more rapid digestion and absorption of amino adds from casein.…”

Section: Hogan (1961) Presented Evidence Showing That the Absorptim Osupporting

confidence: 63%

Influence of dietary nitrogen sources on amino acids in plasma and abomasal ingesta from sheep

Poley

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“…Wheeler and Morgan (1958) reported that rats and Denton and Elvehjem (1954)• Longenecker and Hause (1959) reported that plasma amino acid levels in dogs after ingestion of a high protein meal were directly dependent upon the amino acid composition of the pro tein ingested. This was based on the assumption that the in dividual essential amino acids were removed from the blood by the body tissues at rates proportional to the amino acid re quirements of the dog.…”

Section: Portal Versus Systemic Blood Amino Acidsmentioning

confidence: 99%

Influence of protein sources on performance and plasma amino acid patterns of ruminants

Theurer

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The Absorption by Immature and Adult Rats of Amino Acids from Raw and Autoclaved Fresh Pork

Cited by 41 publications

References 9 publications

Amino acid metabolism during prolonged starvation

Amino acid metabolism during prolonged starvation

Influence of dietary nitrogen sources on amino acids in plasma and abomasal ingesta from sheep

Influence of protein sources on performance and plasma amino acid patterns of ruminants

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