Effects of immobilization stress on estrogen-induced surges of luteinizing hormone and prolactin in ovariectomized rats

Kyungyoon Kam, Yongbin Park, Minseok Cheon, Gi Hoon Son, Kyungjin Kim, Kyungza Ryu

Research output: Contribution to journalArticle

31 Citations (Scopus)

Abstract

Reproductive function has been known to be impaired by various kinds of physical and emotional stress, but the mechanism by which stress impairs the reproductive axis has not been dearly understood. In the present study, the effects of immobilization stress were studied on the surges of luteinizing hormone (LH) and prolactin (PRL) induced by 17β-estradiol (E 2) in ovariectomized rats. Two weeks after bilateral ovariectomy, animals were implanted with the capsule containing E 2 or vehicle at 1000 h (designated as d 0). Immobilization was started at 1000 h and continued to 2100 h on d 2. Blood samples were collected according to the time schedule by a jugular vein catheter procedure. Immobilization stress inhibited basal release of LH and abolished E 2-induced LH and PRL surges in ovariectomized (OVX) rats. Daily repeated immobilization (from 1200 h to 1800 h, 6 h/d) for 3 d also abolished LH and PRL surges when examined at 1800 h on d 2. Although daily repeated immobilization stress reduced E 2-induced PRL mRNA levels, this stress failed to change LHβ mRNA levels in the anterior pituitary as determined by Northern blot analysis. Gonadotropin-releasing hormone (GnRH) receptor mRNA levels in the anterior pituitary were lowered by immobilization stress in the OVX, E 2-treated group. Dopamine D2 receptor mRNA levels in the anterior pituitary of OVX, E 2-treated rats were significantly decreased at 1800 h, compared with those at 1000 h. However, immobilization prevented a decrease in dopamine D2 receptor mRNA levels at 1800 h. GnRH content was increased in the mediobasal hypothalamus by immobilization in the OVX, E 2-treated group, suggesting that GnRH release was inhibited. Interestingly, GnRH mRNA levels in the preoptic area-anterior hypothalamic area were suppressed by immobilization stress in OVX, E 2-treated rats when determined at 1800 h. Therefore, we concluded that immobilization stress blocks E 2-induced LH surge possibly by inhibiting synthesis and release of GnRH at the hypothalamic level, and an increase of dopaminergic activity via D2 receptor at the pituitary level might be involved in the stress blockage of E 2- induced PRL surge.

Original languageEnglish
Pages (from-to)279-287
Number of pages9
JournalEndocrine
Volume12
Issue number3
Publication statusPublished - 2000 Jul 15
Externally publishedYes

Fingerprint

Luteinizing Hormone
Immobilization
Prolactin
Rats
Estrogens
Gonadotropin-Releasing Hormone
Messenger RNA
Dopamine D2 Receptors
LHRH Receptors
Anterior Hypothalamic Nucleus
Catheters
Preoptic Area
Jugular Veins
Ovariectomy
Capsules
Psychological Stress
Northern Blotting
Estradiol
Hypothalamus
Animals

Keywords

  • Dopamine D2 receptor
  • Gonadotropin- releasing hormone
  • Gonadotropin-releasing hormone receptor
  • Immobilization stress
  • Luteinizing hormone
  • Prolactin

ASJC Scopus subject areas

  • Endocrinology

Cite this

Effects of immobilization stress on estrogen-induced surges of luteinizing hormone and prolactin in ovariectomized rats. / Kam, Kyungyoon; Park, Yongbin; Cheon, Minseok; Son, Gi Hoon; Kim, Kyungjin; Ryu, Kyungza.

In: Endocrine, Vol. 12, No. 3, 15.07.2000, p. 279-287.

Research output: Contribution to journalArticle

Kam, Kyungyoon ; Park, Yongbin ; Cheon, Minseok ; Son, Gi Hoon ; Kim, Kyungjin ; Ryu, Kyungza. / Effects of immobilization stress on estrogen-induced surges of luteinizing hormone and prolactin in ovariectomized rats. In: Endocrine. 2000 ; Vol. 12, No. 3. pp. 279-287.
@article{192cde7e67d74805bc189b6c006e0eb7,
title = "Effects of immobilization stress on estrogen-induced surges of luteinizing hormone and prolactin in ovariectomized rats",
abstract = "Reproductive function has been known to be impaired by various kinds of physical and emotional stress, but the mechanism by which stress impairs the reproductive axis has not been dearly understood. In the present study, the effects of immobilization stress were studied on the surges of luteinizing hormone (LH) and prolactin (PRL) induced by 17β-estradiol (E 2) in ovariectomized rats. Two weeks after bilateral ovariectomy, animals were implanted with the capsule containing E 2 or vehicle at 1000 h (designated as d 0). Immobilization was started at 1000 h and continued to 2100 h on d 2. Blood samples were collected according to the time schedule by a jugular vein catheter procedure. Immobilization stress inhibited basal release of LH and abolished E 2-induced LH and PRL surges in ovariectomized (OVX) rats. Daily repeated immobilization (from 1200 h to 1800 h, 6 h/d) for 3 d also abolished LH and PRL surges when examined at 1800 h on d 2. Although daily repeated immobilization stress reduced E 2-induced PRL mRNA levels, this stress failed to change LHβ mRNA levels in the anterior pituitary as determined by Northern blot analysis. Gonadotropin-releasing hormone (GnRH) receptor mRNA levels in the anterior pituitary were lowered by immobilization stress in the OVX, E 2-treated group. Dopamine D2 receptor mRNA levels in the anterior pituitary of OVX, E 2-treated rats were significantly decreased at 1800 h, compared with those at 1000 h. However, immobilization prevented a decrease in dopamine D2 receptor mRNA levels at 1800 h. GnRH content was increased in the mediobasal hypothalamus by immobilization in the OVX, E 2-treated group, suggesting that GnRH release was inhibited. Interestingly, GnRH mRNA levels in the preoptic area-anterior hypothalamic area were suppressed by immobilization stress in OVX, E 2-treated rats when determined at 1800 h. Therefore, we concluded that immobilization stress blocks E 2-induced LH surge possibly by inhibiting synthesis and release of GnRH at the hypothalamic level, and an increase of dopaminergic activity via D2 receptor at the pituitary level might be involved in the stress blockage of E 2- induced PRL surge.",
keywords = "Dopamine D2 receptor, Gonadotropin- releasing hormone, Gonadotropin-releasing hormone receptor, Immobilization stress, Luteinizing hormone, Prolactin",
author = "Kyungyoon Kam and Yongbin Park and Minseok Cheon and Son, {Gi Hoon} and Kyungjin Kim and Kyungza Ryu",
year = "2000",
month = "7",
day = "15",
language = "English",
volume = "12",
pages = "279--287",
journal = "The BMJ",
issn = "0730-6512",
publisher = "Kluwer Academic Publishers",
number = "3",

}

TY - JOUR

T1 - Effects of immobilization stress on estrogen-induced surges of luteinizing hormone and prolactin in ovariectomized rats

AU - Kam, Kyungyoon

AU - Park, Yongbin

AU - Cheon, Minseok

AU - Son, Gi Hoon

AU - Kim, Kyungjin

AU - Ryu, Kyungza

PY - 2000/7/15

Y1 - 2000/7/15

N2 - Reproductive function has been known to be impaired by various kinds of physical and emotional stress, but the mechanism by which stress impairs the reproductive axis has not been dearly understood. In the present study, the effects of immobilization stress were studied on the surges of luteinizing hormone (LH) and prolactin (PRL) induced by 17β-estradiol (E 2) in ovariectomized rats. Two weeks after bilateral ovariectomy, animals were implanted with the capsule containing E 2 or vehicle at 1000 h (designated as d 0). Immobilization was started at 1000 h and continued to 2100 h on d 2. Blood samples were collected according to the time schedule by a jugular vein catheter procedure. Immobilization stress inhibited basal release of LH and abolished E 2-induced LH and PRL surges in ovariectomized (OVX) rats. Daily repeated immobilization (from 1200 h to 1800 h, 6 h/d) for 3 d also abolished LH and PRL surges when examined at 1800 h on d 2. Although daily repeated immobilization stress reduced E 2-induced PRL mRNA levels, this stress failed to change LHβ mRNA levels in the anterior pituitary as determined by Northern blot analysis. Gonadotropin-releasing hormone (GnRH) receptor mRNA levels in the anterior pituitary were lowered by immobilization stress in the OVX, E 2-treated group. Dopamine D2 receptor mRNA levels in the anterior pituitary of OVX, E 2-treated rats were significantly decreased at 1800 h, compared with those at 1000 h. However, immobilization prevented a decrease in dopamine D2 receptor mRNA levels at 1800 h. GnRH content was increased in the mediobasal hypothalamus by immobilization in the OVX, E 2-treated group, suggesting that GnRH release was inhibited. Interestingly, GnRH mRNA levels in the preoptic area-anterior hypothalamic area were suppressed by immobilization stress in OVX, E 2-treated rats when determined at 1800 h. Therefore, we concluded that immobilization stress blocks E 2-induced LH surge possibly by inhibiting synthesis and release of GnRH at the hypothalamic level, and an increase of dopaminergic activity via D2 receptor at the pituitary level might be involved in the stress blockage of E 2- induced PRL surge.

AB - Reproductive function has been known to be impaired by various kinds of physical and emotional stress, but the mechanism by which stress impairs the reproductive axis has not been dearly understood. In the present study, the effects of immobilization stress were studied on the surges of luteinizing hormone (LH) and prolactin (PRL) induced by 17β-estradiol (E 2) in ovariectomized rats. Two weeks after bilateral ovariectomy, animals were implanted with the capsule containing E 2 or vehicle at 1000 h (designated as d 0). Immobilization was started at 1000 h and continued to 2100 h on d 2. Blood samples were collected according to the time schedule by a jugular vein catheter procedure. Immobilization stress inhibited basal release of LH and abolished E 2-induced LH and PRL surges in ovariectomized (OVX) rats. Daily repeated immobilization (from 1200 h to 1800 h, 6 h/d) for 3 d also abolished LH and PRL surges when examined at 1800 h on d 2. Although daily repeated immobilization stress reduced E 2-induced PRL mRNA levels, this stress failed to change LHβ mRNA levels in the anterior pituitary as determined by Northern blot analysis. Gonadotropin-releasing hormone (GnRH) receptor mRNA levels in the anterior pituitary were lowered by immobilization stress in the OVX, E 2-treated group. Dopamine D2 receptor mRNA levels in the anterior pituitary of OVX, E 2-treated rats were significantly decreased at 1800 h, compared with those at 1000 h. However, immobilization prevented a decrease in dopamine D2 receptor mRNA levels at 1800 h. GnRH content was increased in the mediobasal hypothalamus by immobilization in the OVX, E 2-treated group, suggesting that GnRH release was inhibited. Interestingly, GnRH mRNA levels in the preoptic area-anterior hypothalamic area were suppressed by immobilization stress in OVX, E 2-treated rats when determined at 1800 h. Therefore, we concluded that immobilization stress blocks E 2-induced LH surge possibly by inhibiting synthesis and release of GnRH at the hypothalamic level, and an increase of dopaminergic activity via D2 receptor at the pituitary level might be involved in the stress blockage of E 2- induced PRL surge.

KW - Dopamine D2 receptor

KW - Gonadotropin- releasing hormone

KW - Gonadotropin-releasing hormone receptor

KW - Immobilization stress

KW - Luteinizing hormone

KW - Prolactin

UR - http://www.scopus.com/inward/record.url?scp=0033932104&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0033932104&partnerID=8YFLogxK

M3 - Article

C2 - 10963049

AN - SCOPUS:0033932104

VL - 12

SP - 279

EP - 287

JO - The BMJ

JF - The BMJ

SN - 0730-6512

IS - 3

ER -