| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
ARTICLES |
Reproductive Biology Section, Departments of Obstetrics/Gynecology and Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06520-8063
Address all correspondence and requests for reprints to: Pinar H. Kodaman, Reproductive Biology Section, Department of Obstetrics and Gynecology, Yale University School of Medicine, P.O. Box 208063, New Haven, Connecticut 06520-8063. E-mail: kodamaph{at}biomed.med.yale.edu
Ascorbic acid is concentrated in granulosa cells of the follicle, and ascorbate deficiency causes follicular atresia. Dehydroascorbic acid (DHAA), the oxidized form of ascorbic acid, serves as an important source for the recycling of ascorbate. As we previously demonstrated endocrine up-regulation of ascorbic acid transport by granulosa cells, we investigated DHAA as an alternate source of ascorbate in the follicle. Granulosa cells were cultured for 24 h, and DHAA uptake was initiated by the addition of 14C-labeled ascorbic acid (300 µM) in the presence of ascorbic acid oxidase (2 U/ml), which catalyzes DHAA production. Almost 90% of accumulated DHAA was present as ascorbic acid within 2 h. Preculture of cells for 24 h with FSH (50 ng/ml) and IGF-I (30 ng/ml) significantly stimulated DHAA uptake compared with the control (158 ± 16 vs. 43 ± 8 pmol/106 cells, respectively). DHAA uptake by granulosa cells was inhibited by D-glucose (ID50, approximately 2.5 mM) and by the glucose transport inhibitors phloretin (200 µM) and cytochalasin B (10 µM), which reduced uptake to 13 ± 2% and 8 ± 3% of the control, respectively. Northern and Western analysis of GLUT1 in granulosa cells following 24 h coincubation with FSH and IGF-I revealed up-regulation of GLUT1 at both the messenger RNA and protein levels (1.6- and 1.3-fold of control, respectively), suggesting that the stimulatory effects of FSH and IGF-I on DHAA transport are mediated by the induction of GLUT1. GLUT4 protein was not detectable by Western analysis. Endocrine-regulated DHAA transport may represent an important mechanism for maintaining adequate antioxidant tone within the developing follicle.
This article has been cited by other articles:
 |
|
 |
|
  Y. Li and H. E. Schellhorn New Developments and Novel Therapeutic Perspectives for Vitamin C J. Nutr., October 1, 2007; 137(10): 2171 - 2184. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 H Nishimoto, R Matsutani, S Yamamoto, T Takahashi, K-G Hayashi, A Miyamoto, S Hamano, and M Tetsuka Gene expression of glucose transporter (GLUT) 1, 3 and 4 in bovine follicle and corpus luteum J. Endocrinol., January 1, 2006; 188(1): 111 - 119. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. Roberts, J. Stark, A. Iatropoulou, D. L. Becker, S. Franks, and K. Hardy Energy Substrate Metabolism of Mouse Cumulus-Oocyte Complexes: Response to Follicle-Stimulating Hormone Is Mediated by the Phosphatidylinositol 3-Kinase Pathway and Is Associated with Oocyte Maturation Biol Reprod, July 1, 2004; 71(1): 199 - 209. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 E. A. Lutsenko, J. M. Carcamo, and D. W. Golde A Human Sodium-Dependent Vitamin C Transporter 2 Isoform Acts as a Dominant-Negative Inhibitor of Ascorbic Acid Transport Mol. Cell. Biol., April 15, 2004; 24(8): 3150 - 3156. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. H. Kodaman and H. R. Behrman Endocrine-Regulated and Protein Kinase C-Dependent Generation of Superoxide by Rat Preovulatory Follicles Endocrinology, February 1, 2001; 142(2): 687 - 693. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Endocrinology | Endocrine Reviews | J. Clin. End. & Metab. |
| Molecular Endocrinology | Recent Prog. Horm. Res. | All Endocrine Journals |
