Leucine and Histidine Tolerance in the Human

Blood plasma free amino acid studies in swine

“…This is in agreement with the results reported by Steele and Le Bovit (1951) in humans, after which time the curve gradually fell, until they generally approached the control level after 180 minutes.…”

“…Further reports on the problem (King and Rapport, 1933;Steele and Le Bovit, 1951) indicated that the fast removal of amino acids from the blood is not due to abnormally high excretion rates through the urine. It was therefore concluded that the amino acids are apparently concentrated at various rates in the different tissues of the organism.…”

“…Steele and Le Bovit (1951) administered purified amino acids, one at a time and together to humans in a fasting state. After the ingestion of a large dose of leucine or histidine the-plasma concentration of the administered amino acids reached very high levels, with peaks at 30 minutes.…”

“…This conclusion, however, is not unanimously accepted, and a different rate of absorption for free and protein-bound amino acids seems to have the favor of some researchers (Steele and Le Bovit, 1951). Guggenheim jït al.…”

Relationship of blood plasma free amino acids and ingested protein in swine

“…After ingestion of tyrosine, the tyrosine plasma level increased but not that of phenylalanine. Steele and LeBovit (1951) administered purified amino acids, one at a time and together to humans in a fasting state. After the ingestion of a large amount of leucine or histidine, the plasma concentration of the ingested amino acids reached very high levels.…”