Evidence for coupling of phosphotyrosine phosphatase to gonadotropin-releasing hormone receptor in ovarian carcinoma membrane
✍ Scribed by Atsushi Imai; Hiroshi Takagi; Tatsuro Furui; Shinji Horibe; Tatsuo Fuseya; Teruhiko Tamaya
- Publisher
- John Wiley and Sons
- Year
- 1996
- Tongue
- English
- Weight
- 510 KB
- Volume
- 77
- Category
- Article
- ISSN
- 0008-543X
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✦ Synopsis
BACKGROUND.
Gonadotropin-releasing hormone (Gn-RH) receptor (Gn-RHR) has been demonstrated in epithelial ovarian carcinoma (Imai et al., Cancer. 1994;74:2555-61). To examine whether Gn-RHR mediates direct antiproliferative effects, we attempted to determine stimulatory regulation by Gn-RH of phosphotyrosine phosphatase (PTP) activity in plasma membranes isolated from ovarian carcinoma samples.
METHODS.
Surgically removed ovarian carcinomas were screened for Gn-RHR expression prior to plasma membrane isolation. The phosphotyrosine level was observed by: (1) immunoblotting of membrane extracts with antiphosphotyrosine antibodies, and (2) dephosphorylation from 3LP-labeled membrane protein. Membrane PTP activity was determined using the synthetic substrate p-nitrophenyl in a spectrophotometric assay.