Evidence for the Biosynthesis of a Prolactin-Releasing Factor From the Ovine Pars Tuberalis, Which is Distinct from Thyrotropin-Releasing Hormone

David Grey Hazlerigg

Research output: Contribution to journalArticle

24 Citations (Scopus)

Abstract

This study demonstrates the presence of two prolactin-releasing (PR) factors in media conditioned by primary pars tuberalis cells prepared from dispersed pars tuberalis tissue. One factor was identified as thyrotropin-releasing hormone (TRH) on the basis of immunoreactivity and following purification by high-performance liquid chromatography and mass spectrometry. The origin of TRH in the pars tuberalis conditioned media was investigated by measuring the expression of glutaminyl-cyclase (QC) by in situ hybridization. QC expression was not detected in pars tuberalis-specific cells, but was relatively abundant in cells in the pars distalis and hypothalamic paraventricular nucleus. These data suggest that TRH is not synthesized by the ovine pars tuberalis and more likely originated from the hypothalamic neuronal processes from the paraventricular nucleus that terminate in the median eminence. The second component of the conditioned media PR bioactivity was insensitive to the TRH-antiserum, less than 1 kDa and was not retained by the C18 reverse-phase column. The biosynthesis of the PR bioactivity by pars tuberalis cells was investigated using cycloheximide, forskolin and melatonin. Cycloheximide reduced the level of PR bioactivity produced by the pars tuberalis cells. Melatonin inhibited the increased level of PR bioactivity stimulated by forskolin. Collectively, these data demonstrate the synthesis of at least one regulator of prolactin secretion by ovine pars tuberalis-specific cells.

Original languageEnglish
Pages (from-to)945-954
Number of pages9
JournalJournal of Neuroendocrinology
Volume14
DOIs
Publication statusPublished - 2002

Keywords

  • pituitary gland
  • median eminence
  • lactotrophs
  • in situ hybridization
  • PRF
  • melatonin
  • MELATONIN RECEPTORS
  • EXPRESSION CLONING
  • PITUITARY
  • SIGNAL
  • DAYLENGTH
  • SECRETION
  • CYCLES
  • GLAND
  • CELLS

Cite this

@article{fcf52d8dd1e34b0bb556a77af57a9ce7,
title = "Evidence for the Biosynthesis of a Prolactin-Releasing Factor From the Ovine Pars Tuberalis, Which is Distinct from Thyrotropin-Releasing Hormone",
abstract = "This study demonstrates the presence of two prolactin-releasing (PR) factors in media conditioned by primary pars tuberalis cells prepared from dispersed pars tuberalis tissue. One factor was identified as thyrotropin-releasing hormone (TRH) on the basis of immunoreactivity and following purification by high-performance liquid chromatography and mass spectrometry. The origin of TRH in the pars tuberalis conditioned media was investigated by measuring the expression of glutaminyl-cyclase (QC) by in situ hybridization. QC expression was not detected in pars tuberalis-specific cells, but was relatively abundant in cells in the pars distalis and hypothalamic paraventricular nucleus. These data suggest that TRH is not synthesized by the ovine pars tuberalis and more likely originated from the hypothalamic neuronal processes from the paraventricular nucleus that terminate in the median eminence. The second component of the conditioned media PR bioactivity was insensitive to the TRH-antiserum, less than 1 kDa and was not retained by the C18 reverse-phase column. The biosynthesis of the PR bioactivity by pars tuberalis cells was investigated using cycloheximide, forskolin and melatonin. Cycloheximide reduced the level of PR bioactivity produced by the pars tuberalis cells. Melatonin inhibited the increased level of PR bioactivity stimulated by forskolin. Collectively, these data demonstrate the synthesis of at least one regulator of prolactin secretion by ovine pars tuberalis-specific cells.",
keywords = "pituitary gland, median eminence, lactotrophs, in situ hybridization, PRF, melatonin, MELATONIN RECEPTORS, EXPRESSION CLONING, PITUITARY, SIGNAL, DAYLENGTH, SECRETION, CYCLES, GLAND, CELLS",
author = "Hazlerigg, {David Grey}",
year = "2002",
doi = "10.1046/j.1365-2826.2002.00848.x",
language = "English",
volume = "14",
pages = "945--954",
journal = "Journal of Neuroendocrinology",
issn = "0953-8194",
publisher = "Wiley-Blackwell",

}

TY - JOUR

T1 - Evidence for the Biosynthesis of a Prolactin-Releasing Factor From the Ovine Pars Tuberalis, Which is Distinct from Thyrotropin-Releasing Hormone

AU - Hazlerigg, David Grey

PY - 2002

Y1 - 2002

N2 - This study demonstrates the presence of two prolactin-releasing (PR) factors in media conditioned by primary pars tuberalis cells prepared from dispersed pars tuberalis tissue. One factor was identified as thyrotropin-releasing hormone (TRH) on the basis of immunoreactivity and following purification by high-performance liquid chromatography and mass spectrometry. The origin of TRH in the pars tuberalis conditioned media was investigated by measuring the expression of glutaminyl-cyclase (QC) by in situ hybridization. QC expression was not detected in pars tuberalis-specific cells, but was relatively abundant in cells in the pars distalis and hypothalamic paraventricular nucleus. These data suggest that TRH is not synthesized by the ovine pars tuberalis and more likely originated from the hypothalamic neuronal processes from the paraventricular nucleus that terminate in the median eminence. The second component of the conditioned media PR bioactivity was insensitive to the TRH-antiserum, less than 1 kDa and was not retained by the C18 reverse-phase column. The biosynthesis of the PR bioactivity by pars tuberalis cells was investigated using cycloheximide, forskolin and melatonin. Cycloheximide reduced the level of PR bioactivity produced by the pars tuberalis cells. Melatonin inhibited the increased level of PR bioactivity stimulated by forskolin. Collectively, these data demonstrate the synthesis of at least one regulator of prolactin secretion by ovine pars tuberalis-specific cells.

AB - This study demonstrates the presence of two prolactin-releasing (PR) factors in media conditioned by primary pars tuberalis cells prepared from dispersed pars tuberalis tissue. One factor was identified as thyrotropin-releasing hormone (TRH) on the basis of immunoreactivity and following purification by high-performance liquid chromatography and mass spectrometry. The origin of TRH in the pars tuberalis conditioned media was investigated by measuring the expression of glutaminyl-cyclase (QC) by in situ hybridization. QC expression was not detected in pars tuberalis-specific cells, but was relatively abundant in cells in the pars distalis and hypothalamic paraventricular nucleus. These data suggest that TRH is not synthesized by the ovine pars tuberalis and more likely originated from the hypothalamic neuronal processes from the paraventricular nucleus that terminate in the median eminence. The second component of the conditioned media PR bioactivity was insensitive to the TRH-antiserum, less than 1 kDa and was not retained by the C18 reverse-phase column. The biosynthesis of the PR bioactivity by pars tuberalis cells was investigated using cycloheximide, forskolin and melatonin. Cycloheximide reduced the level of PR bioactivity produced by the pars tuberalis cells. Melatonin inhibited the increased level of PR bioactivity stimulated by forskolin. Collectively, these data demonstrate the synthesis of at least one regulator of prolactin secretion by ovine pars tuberalis-specific cells.

KW - pituitary gland

KW - median eminence

KW - lactotrophs

KW - in situ hybridization

KW - PRF

KW - melatonin

KW - MELATONIN RECEPTORS

KW - EXPRESSION CLONING

KW - PITUITARY

KW - SIGNAL

KW - DAYLENGTH

KW - SECRETION

KW - CYCLES

KW - GLAND

KW - CELLS

U2 - 10.1046/j.1365-2826.2002.00848.x

DO - 10.1046/j.1365-2826.2002.00848.x

M3 - Article

VL - 14

SP - 945

EP - 954

JO - Journal of Neuroendocrinology

JF - Journal of Neuroendocrinology

SN - 0953-8194

ER -