Gonadotropin Surge-Attenuating Factor Attenuates Invitro LH-Secretion Induced by Gonadotropin-Releasing-Hormone from Cultured Ovine Pituitary-Cells Only During the Breeding-Season

Paul Alfred Francois Fowler, C TOWNSEND, I E MESSINIS, P CUNNINGHAM, Allan Templeton

Research output: Contribution to journalArticle

Abstract

Primary cultures of ovine pituitaries from adult ewes were used to investigate aspects of gonadotrophin surge-attenuating factor (GnSAF) bioactivity in human follicular fluid (hFF) from superovulated women. During the autumn and first half of the winter, LH secretion induced by gonadotrophin-releasing hormone (GnRH) was markedly reduced (43-5+/-5.2% of control GnRH-induced LH secretion) by incubation for 48 h with steroid-free hFF. For the rest of the year, treatment with the same batch of steroid-free hFF resulted in non-significant reduction or stimulation of GnRH-induced 1-H secretion (71.3+/-13.2 to 117.8+/-11.2% of control GnRH-induced LH secretion). Incubation of pituitary cells for 48 h with oestradiol (1 pmol/l to 1 mumol/l), progesterone (1 pmol/l to 1 mumol/l) or oestradiol and progesterone combined (1 pmol/l to 1 mumol/l) in a two-way titration for 48 h had no significant effect on GnRH-induced LH secretion (83.4+/-7.6 to 110.6+/-5.0% of control secretion). Separating hFF into fractions of different molecular mass by ultrafiltration demonstrated that GnSAF bioactivity was present in a form 10-30 kDa in size. Incubation for 48 h with these fractions had no significant effect on basal FSH secretion but significantly attenuated GnRH-induced LH secretion during the autumn. The same fractions had little effect on GnRH-induced LH secretion from pituitary cells collected during the summer. We conclude that ovine pituitaries display at least partial reduction in sensitivity to GnSAF outside the breeding season. In addition, neither oestradiol nor progesterone singly or in combination caused the observed attenuation of GnRH-induced LH secretion that is ascribed to GnSAF bioactivity.

Original languageEnglish
Pages (from-to)221-227
Number of pages7
JournalJournal of Endocrinology
Volume135
Issue number2
Publication statusPublished - Nov 1992

Keywords

  • human follicular-fluid
  • self-priming action
  • superovulated women
  • factor GNSAF
  • inhibin
  • FSH
  • increases
  • receptors

Cite this

@article{d3c1cdf23c834595b7c9060e39845678,
title = "Gonadotropin Surge-Attenuating Factor Attenuates Invitro LH-Secretion Induced by Gonadotropin-Releasing-Hormone from Cultured Ovine Pituitary-Cells Only During the Breeding-Season",
abstract = "Primary cultures of ovine pituitaries from adult ewes were used to investigate aspects of gonadotrophin surge-attenuating factor (GnSAF) bioactivity in human follicular fluid (hFF) from superovulated women. During the autumn and first half of the winter, LH secretion induced by gonadotrophin-releasing hormone (GnRH) was markedly reduced (43-5+/-5.2{\%} of control GnRH-induced LH secretion) by incubation for 48 h with steroid-free hFF. For the rest of the year, treatment with the same batch of steroid-free hFF resulted in non-significant reduction or stimulation of GnRH-induced 1-H secretion (71.3+/-13.2 to 117.8+/-11.2{\%} of control GnRH-induced LH secretion). Incubation of pituitary cells for 48 h with oestradiol (1 pmol/l to 1 mumol/l), progesterone (1 pmol/l to 1 mumol/l) or oestradiol and progesterone combined (1 pmol/l to 1 mumol/l) in a two-way titration for 48 h had no significant effect on GnRH-induced LH secretion (83.4+/-7.6 to 110.6+/-5.0{\%} of control secretion). Separating hFF into fractions of different molecular mass by ultrafiltration demonstrated that GnSAF bioactivity was present in a form 10-30 kDa in size. Incubation for 48 h with these fractions had no significant effect on basal FSH secretion but significantly attenuated GnRH-induced LH secretion during the autumn. The same fractions had little effect on GnRH-induced LH secretion from pituitary cells collected during the summer. We conclude that ovine pituitaries display at least partial reduction in sensitivity to GnSAF outside the breeding season. In addition, neither oestradiol nor progesterone singly or in combination caused the observed attenuation of GnRH-induced LH secretion that is ascribed to GnSAF bioactivity.",
keywords = "human follicular-fluid, self-priming action, superovulated women, factor GNSAF, inhibin, FSH, increases, receptors",
author = "Fowler, {Paul Alfred Francois} and C TOWNSEND and MESSINIS, {I E} and P CUNNINGHAM and Allan Templeton",
year = "1992",
month = "11",
language = "English",
volume = "135",
pages = "221--227",
journal = "Journal of Endocrinology",
issn = "0022-0795",
publisher = "Society for Endocrinology",
number = "2",

}

TY - JOUR

T1 - Gonadotropin Surge-Attenuating Factor Attenuates Invitro LH-Secretion Induced by Gonadotropin-Releasing-Hormone from Cultured Ovine Pituitary-Cells Only During the Breeding-Season

AU - Fowler, Paul Alfred Francois

AU - TOWNSEND, C

AU - MESSINIS, I E

AU - CUNNINGHAM, P

AU - Templeton, Allan

PY - 1992/11

Y1 - 1992/11

N2 - Primary cultures of ovine pituitaries from adult ewes were used to investigate aspects of gonadotrophin surge-attenuating factor (GnSAF) bioactivity in human follicular fluid (hFF) from superovulated women. During the autumn and first half of the winter, LH secretion induced by gonadotrophin-releasing hormone (GnRH) was markedly reduced (43-5+/-5.2% of control GnRH-induced LH secretion) by incubation for 48 h with steroid-free hFF. For the rest of the year, treatment with the same batch of steroid-free hFF resulted in non-significant reduction or stimulation of GnRH-induced 1-H secretion (71.3+/-13.2 to 117.8+/-11.2% of control GnRH-induced LH secretion). Incubation of pituitary cells for 48 h with oestradiol (1 pmol/l to 1 mumol/l), progesterone (1 pmol/l to 1 mumol/l) or oestradiol and progesterone combined (1 pmol/l to 1 mumol/l) in a two-way titration for 48 h had no significant effect on GnRH-induced LH secretion (83.4+/-7.6 to 110.6+/-5.0% of control secretion). Separating hFF into fractions of different molecular mass by ultrafiltration demonstrated that GnSAF bioactivity was present in a form 10-30 kDa in size. Incubation for 48 h with these fractions had no significant effect on basal FSH secretion but significantly attenuated GnRH-induced LH secretion during the autumn. The same fractions had little effect on GnRH-induced LH secretion from pituitary cells collected during the summer. We conclude that ovine pituitaries display at least partial reduction in sensitivity to GnSAF outside the breeding season. In addition, neither oestradiol nor progesterone singly or in combination caused the observed attenuation of GnRH-induced LH secretion that is ascribed to GnSAF bioactivity.

AB - Primary cultures of ovine pituitaries from adult ewes were used to investigate aspects of gonadotrophin surge-attenuating factor (GnSAF) bioactivity in human follicular fluid (hFF) from superovulated women. During the autumn and first half of the winter, LH secretion induced by gonadotrophin-releasing hormone (GnRH) was markedly reduced (43-5+/-5.2% of control GnRH-induced LH secretion) by incubation for 48 h with steroid-free hFF. For the rest of the year, treatment with the same batch of steroid-free hFF resulted in non-significant reduction or stimulation of GnRH-induced 1-H secretion (71.3+/-13.2 to 117.8+/-11.2% of control GnRH-induced LH secretion). Incubation of pituitary cells for 48 h with oestradiol (1 pmol/l to 1 mumol/l), progesterone (1 pmol/l to 1 mumol/l) or oestradiol and progesterone combined (1 pmol/l to 1 mumol/l) in a two-way titration for 48 h had no significant effect on GnRH-induced LH secretion (83.4+/-7.6 to 110.6+/-5.0% of control secretion). Separating hFF into fractions of different molecular mass by ultrafiltration demonstrated that GnSAF bioactivity was present in a form 10-30 kDa in size. Incubation for 48 h with these fractions had no significant effect on basal FSH secretion but significantly attenuated GnRH-induced LH secretion during the autumn. The same fractions had little effect on GnRH-induced LH secretion from pituitary cells collected during the summer. We conclude that ovine pituitaries display at least partial reduction in sensitivity to GnSAF outside the breeding season. In addition, neither oestradiol nor progesterone singly or in combination caused the observed attenuation of GnRH-induced LH secretion that is ascribed to GnSAF bioactivity.

KW - human follicular-fluid

KW - self-priming action

KW - superovulated women

KW - factor GNSAF

KW - inhibin

KW - FSH

KW - increases

KW - receptors

M3 - Article

VL - 135

SP - 221

EP - 227

JO - Journal of Endocrinology

JF - Journal of Endocrinology

SN - 0022-0795

IS - 2

ER -