| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Articles |
a Dipartimento di Istologia ed Embriologia Medica, University of Rome, "La Sapienza", 00161 Rome, Italy
b Departement de Pathologie, University of Geneva Medical School, Geneva, Switzerland
Plasminogen activators (PAs) have been shown to be synthesized in ovarian follicles of several mammalian species, where they contribute to the ovulation process. The type of PA secreted by granulosa cells is species-specific. In fact, whereas in the rat, gonadotropins stimulate tissue-type PA (tPA) production, the same hormonal stimulation induces urokinase PA (uPA) secretion in mouse cells. To investigate in more detail the hormonal regulation of this system, we used the rat ovary as a model in which we analyzed the production of PAs by theca-interstitial (TI) and granulosa cells obtained from preovulatory follicles after gonadotropin stimulation. In untreated rats, uPA was the predominant enzyme in both TI and granulosa cells. After hormonal stimulation, an increase in uPA and tPA activity was observed in both cell types. Surprisingly, only tPA mRNA increased in a time-dependent manner in both cell types, while uPA mRNA increased only in TI cells and actually decreased in granulosa cells. These divergent results between uPA enzyme activity and mRNA levels in granulosa cells were explained by studying the localization of the enzyme. Analysis of granulosa cell lysates showed that after hormonal stimulation, 60–70% of the uPA behaved as a cell-associated protein, suggesting that uPA, already present in the follicle, accumulates on the granulosa cell surface through binding to specific uPA receptors. The redistribution of uPA in granulosa cells and the differing regulation of the two PAs by gonadotropins in the rat ovary suggest that the two enzymes might have different functions during the ovulation process. Moreover, the ability of antibodies anti-tPA and anti-uPA to significantly inhibit ovulation only when coinjected with hCG confirmed that the PA contribution to ovulation occurs at the initial steps.
1 This work was supported by grants from MURST (60%) to R.C., from MURST (40%) and CNR 95.02941.CT14 to M.S., and from Swiss National Science Foundation to D.B.
2 Correspondence: Rita Canipari, Dipartimento di Istologia ed Embriologia Medica, University of Rome "La Sapienza" Via A. Scarpa 14, 00161 Rome, Italy. FAX: 39 6 4462854; canipari{at}uniroma1.it
3 Current address: Olga Epifano, Laboratory of Cellular and Developmental Biology, NIDDK, National Institutes of Health, 6 Center Drive, Bethesda, MD 20892.
4 These authors contributed equally to this manuscript.
This article has been cited by other articles:
|
|
 |
|
  F. Odet, A. Verot, and B. Le Magueresse-Battistoni The Mouse Testis Is the Source of Various Serine Proteases and Serine Proteinase Inhibitors (SERPINs): Serine Proteases and SERPINs Identified in Leydig Cells Are under Gonadotropin Regulation Endocrinology, September 1, 2006; 147(9): 4374 - 4383. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Cao, J. Buratini Jr, J. G Lussier, P. D Carriere, and C. A Price Expression of protease nexin-1 and plasminogen activators during follicular growth and the periovulatory period in cattle Reproduction, January 1, 2006; 131(1): 125 - 137. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Cao, M. Sahmi, J. G. Lussier, and C. A. Price Plasminogen Activator and Serine Protease Inhibitor-E2 (Protease Nexin-1) Expression by Bovine Granulosa Cells In Vitro Biol Reprod, September 1, 2004; 71(3): 887 - 893. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. P.D. Dow, L. J. Bakke, C. A. Cassar, M. W. Peters, J. R. Pursley, and G. W. Smith Gonadotropin Surge-Induced Up-Regulation of the Plasminogen Activators (Tissue Plasminogen Activator and Urokinase Plasminogen Activator) and the Urokinase Plasminogen Activator Receptor Within Bovine Periovulatory Follicular and Luteal Tissue Biol Reprod, May 1, 2002; 66(5): 1413 - 1421. [Abstract] [Full Text]
|
|
|
|
|
|
R. Apa, A. Lanzone, F. Miceli, S. Vaccari, E. Macchione, M. Stefanini, and R. Canipari Pituitary Adenylate Cyclase-Activating Polypeptide Modulates Plasminogen Activator Expression in Rat Granulosa Cell Biol Reprod, March 1, 2002; 66(3): 830 - 835. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
