Summary
A comparison was made between the transfer of D-isoascorbic acid and L-ascorbic acid into the guinea pig eye. Saturation phenomena are demonstrated. A much higher plasma level is required for D-isoascorbic acid than for ascorbic acid in order to reach the saturation level in the aqueous humour. The affinity of ascorbic acid to the transport substrate is estimated to be 4–5 times higher than that of D-isoascorbic acid. The results are in agreement with the assumption that the transport mechanism is the same for the two substances.
Résumé
On a comparé chez le cobaye la pénétration dans l'oeil de l'acide D-isoascorbique à celle de l'acide L-ascorbique. Des phénomènes de saturation ont été démontrés. Pour obtenir la saturation dans l'humeur aqueuse, il faut atteindre des taux bien plus élevés dans le plasma avec l'acide D-isoascorbique qu'avec l'acide ascorbique. L'affinité de ce dernier au substrat de transport est estimée être 4–5 supérieure à celle de l'acide D-isoascorbique. Les résultats confirment l'hypothèse selon laquelle le mécanisme de transport est le même pour les deux substances.
Zusammenfassung
Bei Meerschweinchen wurde der Übertritt von D-Isoascorbinsäure und von L-Ascorbinsäure verglichen. Saturationsphänomene werden gezeigt. Ein viel höherer Plasmaspiegel ist erforderlich für D-Isoascorbinsäure als für Ascorbinsäure, um ein Saturationsniveau im Kammerwasser zu erreichen. Die Affinität von Ascorbinsäure zum Transportsubstrat wird 4–5 mal höher geschätzt als jene für D-Isoacorbinsäure. Die Resultate stehen in Überein-stimmung mit der Annahme, daß der Transportmechanismus für beide Substanzen der gleiche ist.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Becker, B. Ascorbate transport in guinea pig eyes.Invest. Ophthal. 6,410–415 (1967).
Harris, L. J. Chemical test for vitamin C and the reducing substances present in tumor and other tissues.Nature, 132,27–28 (1933).
Kinsey, V. E. Transfer of ascorbic acid and related compounds across blood-aqueous barrier.Amer. J. Ophthal. 30,1262–1266 (1947).
— Comparative chemistry of aqueous humor in posterior and anterior chambers of rabbit eye.Arch. Ophthal. 50,401–417 (1953).
Linnér, E. Ascorbic acid as a test substance for measuring relative changes in the rate of plasma flow through the ciliary processes. IV. The effect of carotid ligation and cervical symptathectomy in guinea-pigs on the ascorbic acid content of the aqueous humour at varying plasma levels.Actaphysiol. scand. 26,130–147 (1952).
— The rate of plasma flow through the ciliary processes in senile cataracts measured by means of ascorbic acid.Acta ophthal. 32,213–226 (1954).
— The pressure-lowering effect of ascorbic acid in normal human eyes. The Structure of the Eye. II. Symp.,273–283, Stuttgart: F. K. Schattauer (1965).
— Biochemical basis of aqueous secretion. Biochemistry of the Eye, Symp. Tutzing Castle,156–166, (1966). Basel/New York: Karger (1968).
Müller, H. K. Experimentelles zur Katarakt-Genese.Ber. dtsch. ophthal. Ges. 49,168–173 (1932).
Reddy, D. V. N. Chemical composition of normal aqueous humor. Biochemistry of the Eye, Symp. Tutzing Castle,167–186 (1966), Basel/New York: Karger (1968).
Author information
Authors and Affiliations
Additional information
This study was supported by a grant from the Swedish Medical Research Council.
Rights and permissions
About this article
Cite this article
Linnér, E., Nordström, K. Transfer of D-isoascorbic acid and L-ascorbic acid into guinea pig eyes. Doc Ophthalmol 26, 164–170 (1969). https://doi.org/10.1007/BF00943973
Published:
Issue Date:
DOI: https://doi.org/10.1007/BF00943973