Does β-endorphin modulate basal and dopamine-inhibited prolactin release by an action at the anterior pituitary?1

Cecilia Cheung

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

Previous studies performed to elucidate an anterior pituitary site of action for β-endorphin (B-EP) in the regulation of prolactin (PRL) release have been inconclusive. The purpose of the present study was to further investigate if B-EP could stimulate PRL release by a direct action at the anterior pituitary. Anterior pituitaries from ovariectomized rats were dispersed, and the cells were plated in Ham's F-10 medium. Following a 48-hour preincubation period, the effects of B-EP on basal PRL release and on the dopamine-inhibited PRL release were studied over a 24-hour period. Overall, B-EP at concentrations ranging from 10-8 to 10-6 M had no effect on basal release of PRL at 1,3,5 and 24 h, although a small but significant increase of 39% was observed with 10-6 M B-EP at 1 h of incubation only. B-EP at 10-6 M, but not at lower concentrations, significantly suppressed the inhibitory effects of 10-6 M dopamine on PRL release at I h but not at longer periods of incubation. Pretreatment of the cells for 3 h with 10-6 M naloxone completely antagonized the suppressive effect of B-EP on the dopamine-mediated inhibition of PRL release. Naloxone pretreatment of the cells had no effect on basal nor dopamine-inhibited release of PRL. Because of the high concentration of B-EP required to suppress the dopamine inhibition and the transitory nature of this B-EP effect, it is unlikely that the primary site of action for B-EP in regulating PRL release is at the anterior pituitary. However, high concentrations of B-EP may antagonize the inhibitory effect of dopamine on PRL release at the anterior pituitary through a specific opiate-mediated mechanism.

Original languageEnglish (US)
Pages (from-to)489-495
Number of pages7
JournalNeuroendocrinology
Volume39
Issue number6
StatePublished - 1984
Externally publishedYes

Fingerprint

Endorphins
Prolactin
Dopamine
Naloxone
Opiate Alkaloids

Keywords

  • Anterior pituitary
  • Cell culture
  • Naloxone
  • Prolactin
  • β-Endorphin

ASJC Scopus subject areas

  • Endocrinology
  • Endocrinology, Diabetes and Metabolism
  • Cellular and Molecular Neuroscience
  • Endocrine and Autonomic Systems
  • Neuroscience(all)

Cite this

Does β-endorphin modulate basal and dopamine-inhibited prolactin release by an action at the anterior pituitary?1. / Cheung, Cecilia.

In: Neuroendocrinology, Vol. 39, No. 6, 1984, p. 489-495.

Research output: Contribution to journalArticle

@article{0ffb6f4df7994c03bc01d400b71b44e5,
title = "Does β-endorphin modulate basal and dopamine-inhibited prolactin release by an action at the anterior pituitary?1",
abstract = "Previous studies performed to elucidate an anterior pituitary site of action for β-endorphin (B-EP) in the regulation of prolactin (PRL) release have been inconclusive. The purpose of the present study was to further investigate if B-EP could stimulate PRL release by a direct action at the anterior pituitary. Anterior pituitaries from ovariectomized rats were dispersed, and the cells were plated in Ham's F-10 medium. Following a 48-hour preincubation period, the effects of B-EP on basal PRL release and on the dopamine-inhibited PRL release were studied over a 24-hour period. Overall, B-EP at concentrations ranging from 10-8 to 10-6 M had no effect on basal release of PRL at 1,3,5 and 24 h, although a small but significant increase of 39{\%} was observed with 10-6 M B-EP at 1 h of incubation only. B-EP at 10-6 M, but not at lower concentrations, significantly suppressed the inhibitory effects of 10-6 M dopamine on PRL release at I h but not at longer periods of incubation. Pretreatment of the cells for 3 h with 10-6 M naloxone completely antagonized the suppressive effect of B-EP on the dopamine-mediated inhibition of PRL release. Naloxone pretreatment of the cells had no effect on basal nor dopamine-inhibited release of PRL. Because of the high concentration of B-EP required to suppress the dopamine inhibition and the transitory nature of this B-EP effect, it is unlikely that the primary site of action for B-EP in regulating PRL release is at the anterior pituitary. However, high concentrations of B-EP may antagonize the inhibitory effect of dopamine on PRL release at the anterior pituitary through a specific opiate-mediated mechanism.",
keywords = "Anterior pituitary, Cell culture, Naloxone, Prolactin, β-Endorphin",
author = "Cecilia Cheung",
year = "1984",
language = "English (US)",
volume = "39",
pages = "489--495",
journal = "Neuroendocrinology",
issn = "0028-3835",
publisher = "S. Karger AG",
number = "6",

}

TY - JOUR

T1 - Does β-endorphin modulate basal and dopamine-inhibited prolactin release by an action at the anterior pituitary?1

AU - Cheung, Cecilia

PY - 1984

Y1 - 1984

N2 - Previous studies performed to elucidate an anterior pituitary site of action for β-endorphin (B-EP) in the regulation of prolactin (PRL) release have been inconclusive. The purpose of the present study was to further investigate if B-EP could stimulate PRL release by a direct action at the anterior pituitary. Anterior pituitaries from ovariectomized rats were dispersed, and the cells were plated in Ham's F-10 medium. Following a 48-hour preincubation period, the effects of B-EP on basal PRL release and on the dopamine-inhibited PRL release were studied over a 24-hour period. Overall, B-EP at concentrations ranging from 10-8 to 10-6 M had no effect on basal release of PRL at 1,3,5 and 24 h, although a small but significant increase of 39% was observed with 10-6 M B-EP at 1 h of incubation only. B-EP at 10-6 M, but not at lower concentrations, significantly suppressed the inhibitory effects of 10-6 M dopamine on PRL release at I h but not at longer periods of incubation. Pretreatment of the cells for 3 h with 10-6 M naloxone completely antagonized the suppressive effect of B-EP on the dopamine-mediated inhibition of PRL release. Naloxone pretreatment of the cells had no effect on basal nor dopamine-inhibited release of PRL. Because of the high concentration of B-EP required to suppress the dopamine inhibition and the transitory nature of this B-EP effect, it is unlikely that the primary site of action for B-EP in regulating PRL release is at the anterior pituitary. However, high concentrations of B-EP may antagonize the inhibitory effect of dopamine on PRL release at the anterior pituitary through a specific opiate-mediated mechanism.

AB - Previous studies performed to elucidate an anterior pituitary site of action for β-endorphin (B-EP) in the regulation of prolactin (PRL) release have been inconclusive. The purpose of the present study was to further investigate if B-EP could stimulate PRL release by a direct action at the anterior pituitary. Anterior pituitaries from ovariectomized rats were dispersed, and the cells were plated in Ham's F-10 medium. Following a 48-hour preincubation period, the effects of B-EP on basal PRL release and on the dopamine-inhibited PRL release were studied over a 24-hour period. Overall, B-EP at concentrations ranging from 10-8 to 10-6 M had no effect on basal release of PRL at 1,3,5 and 24 h, although a small but significant increase of 39% was observed with 10-6 M B-EP at 1 h of incubation only. B-EP at 10-6 M, but not at lower concentrations, significantly suppressed the inhibitory effects of 10-6 M dopamine on PRL release at I h but not at longer periods of incubation. Pretreatment of the cells for 3 h with 10-6 M naloxone completely antagonized the suppressive effect of B-EP on the dopamine-mediated inhibition of PRL release. Naloxone pretreatment of the cells had no effect on basal nor dopamine-inhibited release of PRL. Because of the high concentration of B-EP required to suppress the dopamine inhibition and the transitory nature of this B-EP effect, it is unlikely that the primary site of action for B-EP in regulating PRL release is at the anterior pituitary. However, high concentrations of B-EP may antagonize the inhibitory effect of dopamine on PRL release at the anterior pituitary through a specific opiate-mediated mechanism.

KW - Anterior pituitary

KW - Cell culture

KW - Naloxone

KW - Prolactin

KW - β-Endorphin

UR - http://www.scopus.com/inward/record.url?scp=0021746212&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0021746212&partnerID=8YFLogxK

M3 - Article

VL - 39

SP - 489

EP - 495

JO - Neuroendocrinology

JF - Neuroendocrinology

SN - 0028-3835

IS - 6

ER -