Catecholaminergic control of intracellular free calcium and β-endorphin secretion of rat pituitary intermediate lobe cells

Z. Némethy, G. Horváth, G. Makara, Z. Ács, I. Barna

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

Individual melanotropes and intermediate lobes were tested to elucidate the role of α- and β-adrenergic and D-2 dopamine receptors in the regulation of concentration of intracellular free calcium ([Ca2+](i)) and release of β-endorphin. Hormone secretion was studied in a superfusion system, while [Ca2+](i) was measured microspectrofluorimetrically. Noradrenaline (1 μM) resulted in a slight decrease, then a marked increase in [Ca2+](i) and secretion of β-endorphin. The nonselective β-adrenergic agonist isoproterenol (1 μM) increased [Ca2+](i) and secretion of β-endorphin; this effect was blocked by the β-antagonist propranolol (10 μM). The α1-adrenergic agonist phenylephrine (1 μM) increased [Ca2+](i) and B-endorphin secretion, but this effect was not blocked by terazosin or prazosin (α1-adrenergic antagonists, 1 μM). Administration of the α2-adrenergic agonist xylazine (1 μM) increased [Ca2+](i) but did not affect secretion of the hormone. Biphasic effect of noradrenaline was tested in presence of adrenergic and dopaminergic antagonists. The noradrenaline-induced rise in [Ca2+](i) and β-endorphin secretion was decreased by propranolol, but this drug did not modify the inhibition. In the presence of 1 μM sulpiride (selective D-2 dopaminergic antagonist), the inhibitory phase of the curve was abolished, and the subsequent increase was reduced. This suggests that activation of dopamine D-2 receptors is involved not only in the inhibition, but also in the subsequent increase, which may originate from a rebound after the termination of the activation of these inhibitory receptors. Our data suggest the presence of several distinct types of catecholamine receptors in the rat intermediate lobe, and the dominant involvement of D-2 and β-adrenergic receptors in the noradrenaline-induced regulation of melanotropes.

Original languageEnglish
Pages (from-to)85-91
Number of pages7
JournalJournal of Neuroendocrinology
Volume10
Issue number2
Publication statusPublished - Feb 1998

Fingerprint

Intermediate Pituitary Gland
Endorphins
Adrenergic Agonists
Calcium
Norepinephrine
Terazosin
Adrenergic Antagonists
Dopamine Antagonists
Propranolol
Catecholamine Receptors
Hormones
Xylazine
Sulpiride
Prazosin
Dopamine Receptors
Phenylephrine
Isoproterenol
Adrenergic Agents
Adrenergic Receptors
Dopamine

Keywords

  • β-endorphin
  • Adrenergic
  • Calcium concentration
  • Intermediate lobe
  • Melanotrope
  • Noradrenaline
  • Pituitary

ASJC Scopus subject areas

  • Endocrinology
  • Neuroscience(all)

Cite this

Catecholaminergic control of intracellular free calcium and β-endorphin secretion of rat pituitary intermediate lobe cells. / Némethy, Z.; Horváth, G.; Makara, G.; Ács, Z.; Barna, I.

In: Journal of Neuroendocrinology, Vol. 10, No. 2, 02.1998, p. 85-91.

Research output: Contribution to journalArticle

@article{e0c9108765404f38a2cd989da9cd1f88,
title = "Catecholaminergic control of intracellular free calcium and β-endorphin secretion of rat pituitary intermediate lobe cells",
abstract = "Individual melanotropes and intermediate lobes were tested to elucidate the role of α- and β-adrenergic and D-2 dopamine receptors in the regulation of concentration of intracellular free calcium ([Ca2+](i)) and release of β-endorphin. Hormone secretion was studied in a superfusion system, while [Ca2+](i) was measured microspectrofluorimetrically. Noradrenaline (1 μM) resulted in a slight decrease, then a marked increase in [Ca2+](i) and secretion of β-endorphin. The nonselective β-adrenergic agonist isoproterenol (1 μM) increased [Ca2+](i) and secretion of β-endorphin; this effect was blocked by the β-antagonist propranolol (10 μM). The α1-adrenergic agonist phenylephrine (1 μM) increased [Ca2+](i) and B-endorphin secretion, but this effect was not blocked by terazosin or prazosin (α1-adrenergic antagonists, 1 μM). Administration of the α2-adrenergic agonist xylazine (1 μM) increased [Ca2+](i) but did not affect secretion of the hormone. Biphasic effect of noradrenaline was tested in presence of adrenergic and dopaminergic antagonists. The noradrenaline-induced rise in [Ca2+](i) and β-endorphin secretion was decreased by propranolol, but this drug did not modify the inhibition. In the presence of 1 μM sulpiride (selective D-2 dopaminergic antagonist), the inhibitory phase of the curve was abolished, and the subsequent increase was reduced. This suggests that activation of dopamine D-2 receptors is involved not only in the inhibition, but also in the subsequent increase, which may originate from a rebound after the termination of the activation of these inhibitory receptors. Our data suggest the presence of several distinct types of catecholamine receptors in the rat intermediate lobe, and the dominant involvement of D-2 and β-adrenergic receptors in the noradrenaline-induced regulation of melanotropes.",
keywords = "β-endorphin, Adrenergic, Calcium concentration, Intermediate lobe, Melanotrope, Noradrenaline, Pituitary",
author = "Z. N{\'e}methy and G. Horv{\'a}th and G. Makara and Z. {\'A}cs and I. Barna",
year = "1998",
month = "2",
language = "English",
volume = "10",
pages = "85--91",
journal = "Journal of Neuroendocrinology",
issn = "0953-8194",
publisher = "Wiley-Blackwell",
number = "2",

}

TY - JOUR

T1 - Catecholaminergic control of intracellular free calcium and β-endorphin secretion of rat pituitary intermediate lobe cells

AU - Némethy, Z.

AU - Horváth, G.

AU - Makara, G.

AU - Ács, Z.

AU - Barna, I.

PY - 1998/2

Y1 - 1998/2

N2 - Individual melanotropes and intermediate lobes were tested to elucidate the role of α- and β-adrenergic and D-2 dopamine receptors in the regulation of concentration of intracellular free calcium ([Ca2+](i)) and release of β-endorphin. Hormone secretion was studied in a superfusion system, while [Ca2+](i) was measured microspectrofluorimetrically. Noradrenaline (1 μM) resulted in a slight decrease, then a marked increase in [Ca2+](i) and secretion of β-endorphin. The nonselective β-adrenergic agonist isoproterenol (1 μM) increased [Ca2+](i) and secretion of β-endorphin; this effect was blocked by the β-antagonist propranolol (10 μM). The α1-adrenergic agonist phenylephrine (1 μM) increased [Ca2+](i) and B-endorphin secretion, but this effect was not blocked by terazosin or prazosin (α1-adrenergic antagonists, 1 μM). Administration of the α2-adrenergic agonist xylazine (1 μM) increased [Ca2+](i) but did not affect secretion of the hormone. Biphasic effect of noradrenaline was tested in presence of adrenergic and dopaminergic antagonists. The noradrenaline-induced rise in [Ca2+](i) and β-endorphin secretion was decreased by propranolol, but this drug did not modify the inhibition. In the presence of 1 μM sulpiride (selective D-2 dopaminergic antagonist), the inhibitory phase of the curve was abolished, and the subsequent increase was reduced. This suggests that activation of dopamine D-2 receptors is involved not only in the inhibition, but also in the subsequent increase, which may originate from a rebound after the termination of the activation of these inhibitory receptors. Our data suggest the presence of several distinct types of catecholamine receptors in the rat intermediate lobe, and the dominant involvement of D-2 and β-adrenergic receptors in the noradrenaline-induced regulation of melanotropes.

AB - Individual melanotropes and intermediate lobes were tested to elucidate the role of α- and β-adrenergic and D-2 dopamine receptors in the regulation of concentration of intracellular free calcium ([Ca2+](i)) and release of β-endorphin. Hormone secretion was studied in a superfusion system, while [Ca2+](i) was measured microspectrofluorimetrically. Noradrenaline (1 μM) resulted in a slight decrease, then a marked increase in [Ca2+](i) and secretion of β-endorphin. The nonselective β-adrenergic agonist isoproterenol (1 μM) increased [Ca2+](i) and secretion of β-endorphin; this effect was blocked by the β-antagonist propranolol (10 μM). The α1-adrenergic agonist phenylephrine (1 μM) increased [Ca2+](i) and B-endorphin secretion, but this effect was not blocked by terazosin or prazosin (α1-adrenergic antagonists, 1 μM). Administration of the α2-adrenergic agonist xylazine (1 μM) increased [Ca2+](i) but did not affect secretion of the hormone. Biphasic effect of noradrenaline was tested in presence of adrenergic and dopaminergic antagonists. The noradrenaline-induced rise in [Ca2+](i) and β-endorphin secretion was decreased by propranolol, but this drug did not modify the inhibition. In the presence of 1 μM sulpiride (selective D-2 dopaminergic antagonist), the inhibitory phase of the curve was abolished, and the subsequent increase was reduced. This suggests that activation of dopamine D-2 receptors is involved not only in the inhibition, but also in the subsequent increase, which may originate from a rebound after the termination of the activation of these inhibitory receptors. Our data suggest the presence of several distinct types of catecholamine receptors in the rat intermediate lobe, and the dominant involvement of D-2 and β-adrenergic receptors in the noradrenaline-induced regulation of melanotropes.

KW - β-endorphin

KW - Adrenergic

KW - Calcium concentration

KW - Intermediate lobe

KW - Melanotrope

KW - Noradrenaline

KW - Pituitary

UR - http://www.scopus.com/inward/record.url?scp=0031951256&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0031951256&partnerID=8YFLogxK

M3 - Article

C2 - 9535054

AN - SCOPUS:0031951256

VL - 10

SP - 85

EP - 91

JO - Journal of Neuroendocrinology

JF - Journal of Neuroendocrinology

SN - 0953-8194

IS - 2

ER -