Changes in zinc uptake in response to ascorbic acid and folic acid in rat liver slices under normal and oxidative stress conditions

Article type: Research Article

Authors: Tupe, R.S. | Chiplonkar, S.A. | Agte, V.V.

Affiliations: Agharkar Research Institute, Pune, India

Note: [] Address for correspondence: Dr. V.V. Agte, Agharkar Research Institute, G. G. Agarkar Road, Pune-411004, India. Tel.: +91 020 5653680; Fax: +91 020 5651542; E-mail: [email protected]

Abstract: Zinc plays a dual role, as an integral part of metabolic machinery and in defense against reactive oxygen species. Hepatocytes are important sites for zinc metabolism for synthesis of zinc metalloproteins and maintaining its homeostasis. However, the factors influencing post absorptive zinc metabolism under normal and oxidative stress (OS) conditions are not well understood. Using rat liver slices, we conducted a series of four in vitro zinc uptake experiments to study influence of ascorbic acid and folic acid in normal and oxidative stress conditions with Zn concentrations representing deficient to excess states (7.7–30.7 millimole/L). Zinc uptakes under OS at these four zinc levels were lower than the normal conditions. Folic acid showed significant inhibitory effect on zinc uptake under both normal and OS conditions in a dose response manner. Nevertheless, dose response of ascorbic acid at four zinc levels indicated its marked enhancing effect under OS condition. Differences in zinc uptake trend lines between the normal and OS conditions for interaction of both the vitamins narrowed down as the zinc levels increased. Our results suggest that folic acid causes inhibitory effect, while ascorbic acid may be protective in OS with reference to zinc uptake.

Keywords: Zinc, ascorbic acid, folic acid, in vitro, liver slice, oxidative stress

Journal: BioFactors, vol. 30, no. 1, pp. 27-34, 2007