Abstract
Intestinal absorption of α-aminoisobutyric acid (AIB), tyrosine (Tyr) and Tyr-D-Ala-Gly (TAG) was studied in vitro in rats of three different ages (4, 14 and 24 months old). When the sacs of everted ileum from the rats were incubated in Krebs-Henseleit buffer solution containing AIB (2.5 × 10−3M), Tyr (5 × 10−5M), or TAG (7.3 × 10−5M) at 37 °C for 20 minutes, the intestinal transmural transport and absorption of AIB and TAG were smaller in 24-month-old rats than in 4-month-old rats with data calculated by moles per weight (mg) of intestine. When data were calculated with moles per length (cm) of intestine, only transmural transport of AIB was smaller. After the sacs were incubated for 60 minutes transmural transport and absorpotion of AIB and Tyr were smaller in 24-month-old rats than in 4-month-old rats with data calculated by intestinal weight. Only transmural transport of tyrosine was smaller in 24-month-old rats when data were calculated by length of intestine. These results indicate that aging has a different effect on intestinal absorption of amino acids than it has on absorption of peptides.
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Huang, JT., Nakajima, T. & Naito, S. Age-related changes of intestinal absorption of α-aminoisobutyric acid, tyrosine and Tyr-D-Ala-Gly in rats. AGE 8, 64–68 (1985). https://doi.org/10.1007/BF02432073
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DOI: https://doi.org/10.1007/BF02432073