Evidence for regulation of basic fibroblast growth factor gene expression by photoperiod and melatonin in the ovine pars tuberalis

E S Graham, D G Hazlerigg, P J Morgan

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8 Citations (Scopus)

Abstract

In the ovine pituitary the in vivo expression of the bFGF gene was studied using in situ hybridisation and Northern analysis. Expression of bFGF mRNA was highest in the pars tuberalis (PT) and zona tuberalis (ZT) and this expression was higher in the pituitaries of animals acclimited to long days than in those from short day housed animals. Expression in the pars intermedia (PI) was also detectable but the pars distalis (PD) showed negligible expression compared with the PT. Regulation of bFGF gene was investigated in primary cultured PT cells. Both forskolin and PMA increased bFGF mRNA expression significantly and melatonin was able to inhibit these effects partially, however there was no independent effect of melatonin on bFGF mRNA levels. Despite the inducibility of the bFGF gene, bFGF protein levels in PT culture media were insensitive to the same stimuli and detectable bFGF protein declined with time. Exogenous bFGF had no effect on c-fos mRNA levels and did not increase prolactin secretion from ovine lactotrophs. In contrast c-fos mRNA was induced in GH3 cells by bFGF. These data suggest that although basic fibroblast growth factor (bFGF) mRNA expression in the ovine PT is photoperiodically-sensitive, it is not directly involved in the seasonal regulation of lactotrophic activity. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.

Original languageEnglish
Pages (from-to)45-53
Number of pages9
JournalMolecular and Cellular Endocrinology
Volume156
Publication statusPublished - 1999

Keywords

  • pars tuberalis
  • melatonin
  • pituitary
  • c-fos
  • pars distalis
  • photoperiod
  • DIFFERENTIAL EXPRESSION
  • PROLACTIN SECRETION
  • FACTOR-II
  • PITUITARY
  • CELLS
  • RECEPTORS
  • HORMONE
  • FAMILY
  • THYROTROPIN
  • DOPAMINE

Cite this

@article{b222ac75df994a768cda1b9047b25c14,
title = "Evidence for regulation of basic fibroblast growth factor gene expression by photoperiod and melatonin in the ovine pars tuberalis",
abstract = "In the ovine pituitary the in vivo expression of the bFGF gene was studied using in situ hybridisation and Northern analysis. Expression of bFGF mRNA was highest in the pars tuberalis (PT) and zona tuberalis (ZT) and this expression was higher in the pituitaries of animals acclimited to long days than in those from short day housed animals. Expression in the pars intermedia (PI) was also detectable but the pars distalis (PD) showed negligible expression compared with the PT. Regulation of bFGF gene was investigated in primary cultured PT cells. Both forskolin and PMA increased bFGF mRNA expression significantly and melatonin was able to inhibit these effects partially, however there was no independent effect of melatonin on bFGF mRNA levels. Despite the inducibility of the bFGF gene, bFGF protein levels in PT culture media were insensitive to the same stimuli and detectable bFGF protein declined with time. Exogenous bFGF had no effect on c-fos mRNA levels and did not increase prolactin secretion from ovine lactotrophs. In contrast c-fos mRNA was induced in GH3 cells by bFGF. These data suggest that although basic fibroblast growth factor (bFGF) mRNA expression in the ovine PT is photoperiodically-sensitive, it is not directly involved in the seasonal regulation of lactotrophic activity. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.",
keywords = "pars tuberalis, melatonin, pituitary, c-fos, pars distalis, photoperiod, DIFFERENTIAL EXPRESSION, PROLACTIN SECRETION, FACTOR-II, PITUITARY, CELLS, RECEPTORS, HORMONE, FAMILY, THYROTROPIN, DOPAMINE",
author = "Graham, {E S} and Hazlerigg, {D G} and Morgan, {P J}",
year = "1999",
language = "English",
volume = "156",
pages = "45--53",
journal = "Molecular and Cellular Endocrinology",
issn = "0303-7207",
publisher = "Elsevier Ireland Ltd",

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TY - JOUR

T1 - Evidence for regulation of basic fibroblast growth factor gene expression by photoperiod and melatonin in the ovine pars tuberalis

AU - Graham, E S

AU - Hazlerigg, D G

AU - Morgan, P J

PY - 1999

Y1 - 1999

N2 - In the ovine pituitary the in vivo expression of the bFGF gene was studied using in situ hybridisation and Northern analysis. Expression of bFGF mRNA was highest in the pars tuberalis (PT) and zona tuberalis (ZT) and this expression was higher in the pituitaries of animals acclimited to long days than in those from short day housed animals. Expression in the pars intermedia (PI) was also detectable but the pars distalis (PD) showed negligible expression compared with the PT. Regulation of bFGF gene was investigated in primary cultured PT cells. Both forskolin and PMA increased bFGF mRNA expression significantly and melatonin was able to inhibit these effects partially, however there was no independent effect of melatonin on bFGF mRNA levels. Despite the inducibility of the bFGF gene, bFGF protein levels in PT culture media were insensitive to the same stimuli and detectable bFGF protein declined with time. Exogenous bFGF had no effect on c-fos mRNA levels and did not increase prolactin secretion from ovine lactotrophs. In contrast c-fos mRNA was induced in GH3 cells by bFGF. These data suggest that although basic fibroblast growth factor (bFGF) mRNA expression in the ovine PT is photoperiodically-sensitive, it is not directly involved in the seasonal regulation of lactotrophic activity. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.

AB - In the ovine pituitary the in vivo expression of the bFGF gene was studied using in situ hybridisation and Northern analysis. Expression of bFGF mRNA was highest in the pars tuberalis (PT) and zona tuberalis (ZT) and this expression was higher in the pituitaries of animals acclimited to long days than in those from short day housed animals. Expression in the pars intermedia (PI) was also detectable but the pars distalis (PD) showed negligible expression compared with the PT. Regulation of bFGF gene was investigated in primary cultured PT cells. Both forskolin and PMA increased bFGF mRNA expression significantly and melatonin was able to inhibit these effects partially, however there was no independent effect of melatonin on bFGF mRNA levels. Despite the inducibility of the bFGF gene, bFGF protein levels in PT culture media were insensitive to the same stimuli and detectable bFGF protein declined with time. Exogenous bFGF had no effect on c-fos mRNA levels and did not increase prolactin secretion from ovine lactotrophs. In contrast c-fos mRNA was induced in GH3 cells by bFGF. These data suggest that although basic fibroblast growth factor (bFGF) mRNA expression in the ovine PT is photoperiodically-sensitive, it is not directly involved in the seasonal regulation of lactotrophic activity. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.

KW - pars tuberalis

KW - melatonin

KW - pituitary

KW - c-fos

KW - pars distalis

KW - photoperiod

KW - DIFFERENTIAL EXPRESSION

KW - PROLACTIN SECRETION

KW - FACTOR-II

KW - PITUITARY

KW - CELLS

KW - RECEPTORS

KW - HORMONE

KW - FAMILY

KW - THYROTROPIN

KW - DOPAMINE

M3 - Article

VL - 156

SP - 45

EP - 53

JO - Molecular and Cellular Endocrinology

JF - Molecular and Cellular Endocrinology

SN - 0303-7207

ER -