Abstract
Extract: Intestinal absorption of proline, hydroxyproline, and glycine was interpreted by investigation of a type I hyperprolinemia patient and six control subjects. Intestinal perfusion was performed.
When proline (Pro), hydroxyproline (OH-Pro), and glycine (Gly) were infused together, an increase in proline concentration did not alter aminoacid uptake in the control subjects; however, in the hyperprolinemia patient, uptake of aminoacids became negligible (Pro, 17–6 μM/min; OH-Pro, 15–0.3 μM/min; and Gly, 13.5–0 μM/min).
When each aminoacid was infused alone at increasing concentrations aminoacid uptake increased in controls; in the hyperprolinemic patient, intestinal absorption was less for glycine and hydroxyproline but aminoacid uptake increased with substrate concentration; however, for proline, the uptake remained constant (16.5–17 μM/min/20 cm of intestinal test segment) (Table 1).
When hydroxyproline was infused with an increased concentration of proline in the hyperprolinemic patient, hydroxyproline uptake first increased (9.8–14.3 μM/min/20 cm) then decreased to its basal value, whereas, in the control subjects, uptake increased without decreasing subsequently.
Speculation: The chronic hyperprolinemia state might entail adaptation of the transport mechanism with the three infused aminoacids (Pro, OH-Pro, and Gly), bringing about an “overflow” of the system similar to that observed in the kidney. However, the inhibition of intestinal iminoacids and glycine transport seems to be due to mechanisms more complex than that of a simple inhibition by proline.
Similar content being viewed by others
Article PDF
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Farriaux, J., Dhondt, J. Type I Hyperprolinemia: A Study of the Intestinal Absorption of Proline, Hydroxyproline, and Glycine. Pediatr Res 10, 550–552 (1976). https://doi.org/10.1203/00006450-197605000-00009
Issue Date:
DOI: https://doi.org/10.1203/00006450-197605000-00009