Ontogeny for absorption of amino acids, dipeptides, and tripeptides
| Species | Transporters | Ontogeny of Oral Absorption | Sampled GIT Tissue | Reference |
|---|---|---|---|---|
| Human | PEPT1 | PEPT1 mRNA levels marginally lower compared with older children (0.8×) | SI | Mooij et al. (2016) |
| Rat | PEPT1 | PEPT1 protein and mRNA increase to elevated levels in immediate postnatal period then decrease to adult level | SI and colon | Miyamoto et al. (1996); Shen et al. (2001); Hussain et al. (2002) |
| Dog | No transporter studies available; amino acid absorption studies are available | AA absorption is high at birth and decreases with PN age | SI and colon | Buddington and Malo (2003) |
| Pig (Yucatan, Tibetan, LandraceXYorkshire; Huangjiang) | PEPT1; EAAC1 | AA absorption, mRNA, and protein levels appear prenatally and peak in PN period, then decline to adult levels | SI and colon | Buddington and Malo (1996); Zhang et al. (1997); Buddington et al. (2001); (2012); Fu et al. (2013); Nosworthy et al. (2013); Wang et al. (2013) |
AA, amino acid; EAAC1, excitatory amino acid carrier 1; PN, postnatal; SI, small intestine.