Characterization and autoradiographical localization of oxytocin receptors within the ovine endometrium in relation to post-partum corpus luteum function

Jacqueline Wallace, Peter John Morgan, R HELLIWELL, Raymond Aitken, M CHEYNE, Lynda Williams

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Abstract

The induction of ovulation in early post-partum ewes is associated with a high incidence of premature luteal regression which is independent of the suckling stimulus but dependent on the stage post partum. The aim of the present study was to determine whether oxytocin receptors are present on uterine endometrium early in the luteal phase and hence ascertain whether oxytocin-induced uterine prostaglandin F2-alpha release is a possible mechanism involved in the premature regression of these post-partum corpora lutea. Ovarian and uterine tissues were collected on day 4 of the cycle in ewes induced to ovulate at either 21 or 35 days post partum (n = 4 per group). A further four cyclic ewes were similarly synchronized to ovulate and acted as controls. Corpora lutea from the 21-day post-partum group were significantly (P < 0.01) smaller, had a lower progesterone content and a reduced capacity to secrete progesterone in vitro than corpora lutea from 35-day post-partum or control ewes.

A highly specific oxytocin receptor ligand I-125-labelled d(CH2)5[Tyr(Me)2,Thr4,Tyr-NH2(9)]-vasotocin was used to localize and characterize high affinity oxytocin receptors in uterine endometrium (dissociation constant 145 pmol/l). Oxytocin receptor concentrations in endometrium from ewes induced to ovulate at 21 days post partum were on average five-fold higher (P < 0.05) than in 35-day post-partum and control groups.

Original languageEnglish
Pages (from-to)253-260
Number of pages9
JournalJournal of Endocrinology
Volume128
Issue number2
DOIs
Publication statusPublished - Feb 1991

Keywords

  • corpora-lutea
  • beef-cows
  • ewe
  • binding
  • progesterone
  • hysterectomy
  • parturition
  • ovulation
  • release
  • uterus

Cite this

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title = "Characterization and autoradiographical localization of oxytocin receptors within the ovine endometrium in relation to post-partum corpus luteum function",
abstract = "The induction of ovulation in early post-partum ewes is associated with a high incidence of premature luteal regression which is independent of the suckling stimulus but dependent on the stage post partum. The aim of the present study was to determine whether oxytocin receptors are present on uterine endometrium early in the luteal phase and hence ascertain whether oxytocin-induced uterine prostaglandin F2-alpha release is a possible mechanism involved in the premature regression of these post-partum corpora lutea. Ovarian and uterine tissues were collected on day 4 of the cycle in ewes induced to ovulate at either 21 or 35 days post partum (n = 4 per group). A further four cyclic ewes were similarly synchronized to ovulate and acted as controls. Corpora lutea from the 21-day post-partum group were significantly (P < 0.01) smaller, had a lower progesterone content and a reduced capacity to secrete progesterone in vitro than corpora lutea from 35-day post-partum or control ewes.A highly specific oxytocin receptor ligand I-125-labelled d(CH2)5[Tyr(Me)2,Thr4,Tyr-NH2(9)]-vasotocin was used to localize and characterize high affinity oxytocin receptors in uterine endometrium (dissociation constant 145 pmol/l). Oxytocin receptor concentrations in endometrium from ewes induced to ovulate at 21 days post partum were on average five-fold higher (P < 0.05) than in 35-day post-partum and control groups.",
keywords = "corpora-lutea, beef-cows, ewe, binding, progesterone, hysterectomy, parturition, ovulation, release, uterus",
author = "Jacqueline Wallace and Morgan, {Peter John} and R HELLIWELL and Raymond Aitken and M CHEYNE and Lynda Williams",
year = "1991",
month = "2",
doi = "10.1677/joe.0.1280253",
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T1 - Characterization and autoradiographical localization of oxytocin receptors within the ovine endometrium in relation to post-partum corpus luteum function

AU - Wallace, Jacqueline

AU - Morgan, Peter John

AU - HELLIWELL, R

AU - Aitken, Raymond

AU - CHEYNE, M

AU - Williams, Lynda

PY - 1991/2

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N2 - The induction of ovulation in early post-partum ewes is associated with a high incidence of premature luteal regression which is independent of the suckling stimulus but dependent on the stage post partum. The aim of the present study was to determine whether oxytocin receptors are present on uterine endometrium early in the luteal phase and hence ascertain whether oxytocin-induced uterine prostaglandin F2-alpha release is a possible mechanism involved in the premature regression of these post-partum corpora lutea. Ovarian and uterine tissues were collected on day 4 of the cycle in ewes induced to ovulate at either 21 or 35 days post partum (n = 4 per group). A further four cyclic ewes were similarly synchronized to ovulate and acted as controls. Corpora lutea from the 21-day post-partum group were significantly (P < 0.01) smaller, had a lower progesterone content and a reduced capacity to secrete progesterone in vitro than corpora lutea from 35-day post-partum or control ewes.A highly specific oxytocin receptor ligand I-125-labelled d(CH2)5[Tyr(Me)2,Thr4,Tyr-NH2(9)]-vasotocin was used to localize and characterize high affinity oxytocin receptors in uterine endometrium (dissociation constant 145 pmol/l). Oxytocin receptor concentrations in endometrium from ewes induced to ovulate at 21 days post partum were on average five-fold higher (P < 0.05) than in 35-day post-partum and control groups.

AB - The induction of ovulation in early post-partum ewes is associated with a high incidence of premature luteal regression which is independent of the suckling stimulus but dependent on the stage post partum. The aim of the present study was to determine whether oxytocin receptors are present on uterine endometrium early in the luteal phase and hence ascertain whether oxytocin-induced uterine prostaglandin F2-alpha release is a possible mechanism involved in the premature regression of these post-partum corpora lutea. Ovarian and uterine tissues were collected on day 4 of the cycle in ewes induced to ovulate at either 21 or 35 days post partum (n = 4 per group). A further four cyclic ewes were similarly synchronized to ovulate and acted as controls. Corpora lutea from the 21-day post-partum group were significantly (P < 0.01) smaller, had a lower progesterone content and a reduced capacity to secrete progesterone in vitro than corpora lutea from 35-day post-partum or control ewes.A highly specific oxytocin receptor ligand I-125-labelled d(CH2)5[Tyr(Me)2,Thr4,Tyr-NH2(9)]-vasotocin was used to localize and characterize high affinity oxytocin receptors in uterine endometrium (dissociation constant 145 pmol/l). Oxytocin receptor concentrations in endometrium from ewes induced to ovulate at 21 days post partum were on average five-fold higher (P < 0.05) than in 35-day post-partum and control groups.

KW - corpora-lutea

KW - beef-cows

KW - ewe

KW - binding

KW - progesterone

KW - hysterectomy

KW - parturition

KW - ovulation

KW - release

KW - uterus

U2 - 10.1677/joe.0.1280253

DO - 10.1677/joe.0.1280253

M3 - Article

VL - 128

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EP - 260

JO - Journal of Endocrinology

JF - Journal of Endocrinology

SN - 0022-0795

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ER -