Graduate Thesis Or Dissertation
 

Nongenomic inhibition of oxytocin binding by progesterone in ovine uteri

Público Deposited

Contenido Descargable

Descargar PDF
https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/pv63g248f

Descriptions

Attribute NameValues
Creator
Abstract
  • Effects of progesterone (P₄) and mifepristone (RU 486) on binding of oxytocin (OT) to its ovine uterine receptor (OTR) were studied in two experiments. Two additional experiments were conducted to evaluate specific binding sites for P4 in endometrial plasma membranes. In Exp. 1, ovariectomized ewes were injected with estradiol-17β (E₂) and P₄ to simulate an abbreviated estrous cycle (7 days) and then treated daily with 25 μg E₂ plus the following steroids for an additional 3 days: Grp. 1) controls (none), 2) 10 mg P₄; 3)10 mg P₄ + 10 mg RU 486. Endometrium removed on Day 11 was stored at -80°C until analyzed for OTR. For Exp. 2, endometrial plasma membranes (1 mg protein/mi) from control ewes were incubated for 1 h (25°C) with the following steroids: 1) controls (C), 2) P₄ (5 ng/mI) and 3) P₄ + RU 486 (10 ng/ml), and analyzed for OTR. Scatchard analysis revealed high affinity OT binding sites (Kd of 1.01 X 10⁻¹⁰M). in vivo and in vitro treatment with P4 suppressed the binding of OT to OTR (p<0.01) and treatment with RU 486 blocked the effect of P₄ (p>O.05). In Exp. 3, membranes recovered from control ewes as in Exp. 1 were analyzed for specificity of P₄ binding using [³H] P₄ and [³H] promegestone (R5020). Scatchard analysis revealed high affinity P4 and R5020 binding sites (Kd 1.2 x 10⁻⁹ and 1.74 x 10⁻¹⁰M, respectively). Binding of [³H] R5020 to plasma membranes was inhibited by competition with a 200-fold excess of unlabeled R5020, P₄, RU 486 and OT (37-49%) but not by E₂, cortisol, or testosterone. In Exp. 4, membranes were incubated in vitro with P₄ or P₄ + RU 486 and then analyzed for specific binding of [³H] R5020. Progestin binding was greater in membranes exposed to P4 compared to controls or those incubated with P₄ + RU 486 (p<0.05). These data suggest a direct interaction between P₄ and OTR at the level of the membrane that suppresses binding of OT to the OTR.
License
Resource Type
Fecha Disponible
Fecha de Emisión
Degree Level
Degree Name
Degree Field
Degree Grantor
Commencement Year
Advisor
Committee Member
Academic Affiliation
Non-Academic Affiliation
Subject
Declaración de derechos
Publisher
Peer Reviewed
Language
Digitization Specifications
  • File scanned at 300 ppi (Monochrome, 256 Grayscale) using Capture Perfect 3.0.82 on a Canon DR-9080C in PDF format. CVista PdfCompressor 4.0 was used for pdf compression and textual OCR.
Replaces

Relaciones

Parents:

This work has no parents.

En Collection:

Elementos

Miniatura Título Fecha de subida Visibilidad Acciones
file details DunlapKathrinA2003.pdf 2017-08-03 Público Descargar