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- Publisher Website: 10.1006/gcen.1993.1007
- Scopus: eid_2-s2.0-0027470681
- PMID: 8094059
- WOS: WOS:A1993KW63000006
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Article: Interactions of gonadal steroids with brain dopamine and gonadotropin- releasing hormone in the control of gonadotropin-II secretion in the goldfish
Title | Interactions of gonadal steroids with brain dopamine and gonadotropin- releasing hormone in the control of gonadotropin-II secretion in the goldfish |
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Authors | |
Issue Date | 1993 |
Publisher | Academic Press. The Journal's web site is located at http://www.elsevier.com/locate/ygcen |
Citation | General And Comparative Endocrinology, 1993, v. 89 n. 1, p. 39-50 How to Cite? |
Abstract | In goldfish it is known that intraperitoneal implantation with testosterone (T) or estradiol (E 2) potentiates the serum gonadotropin-II (GtH-II) response to gonadotropin-releasing hormone (GnRH) without affecting basal GtH-II levels. Since the release of GtH-II in goldfish is under a tonic dopaminergic inhibitory tone, the possibility of sex steroids modulating brain and pituitary dopamine was examined in vivo and in vitro. Implantation of females with either T or E 2 (100 μg/g in solid silastic pellets) also potentiated the increase in serum GtH-II in response to the dopamine antagonist, domperidone (10 μg/g). High-performance liquid chromatography measurements showed that steroid implantation had no effect on dopamine content in the telencephalon including preoptic area, hypothalamus, and pituitary. However, the present study demonstrates that T or E 2 can increase pituitary dopamine turnover rates following tyrosine hydroxylase inhibition with α-methyl-p-tyrosine (240 μg/g). In vitro perifusion of pars distalis fragments from E 2- or T-treated fish also showed a potentiation of salmon GnRH (sGnRH)-induced GtH-II release compared to controls. However, exposure to pituitary fragments from control and steroid-treated fish to increasing doses of the dopamine agonist LY 171555 did not demonstrate a significant difference in the sensitivity of the gonadotrophs to dopamine. Testosterone- induced alterations in DA turnover are dissociable from the positive action of T on pituitary responsiveness, since the potentiating effect of T implantation was not affected by severe depletion of brain and pituitary DA levels by α-methyl-p-tyrosine pretreatment. These data demonstrate that in gonad-intact goldfish, sex steroids enhance pituitary responsiveness to GnRH but basal serum GtH-II levels are maintained by a concomitant increase in DA turnover in the pituitary. |
Persistent Identifier | http://hdl.handle.net/10722/178552 |
ISSN | 2023 Impact Factor: 2.1 2023 SCImago Journal Rankings: 0.616 |
ISI Accession Number ID |
DC Field | Value | Language |
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dc.contributor.author | Trudeau, VL | en_US |
dc.contributor.author | Sloley, BD | en_US |
dc.contributor.author | Wong, AOL | en_US |
dc.contributor.author | Peter, RE | en_US |
dc.date.accessioned | 2012-12-19T09:48:20Z | - |
dc.date.available | 2012-12-19T09:48:20Z | - |
dc.date.issued | 1993 | en_US |
dc.identifier.citation | General And Comparative Endocrinology, 1993, v. 89 n. 1, p. 39-50 | en_US |
dc.identifier.issn | 0016-6480 | en_US |
dc.identifier.uri | http://hdl.handle.net/10722/178552 | - |
dc.description.abstract | In goldfish it is known that intraperitoneal implantation with testosterone (T) or estradiol (E 2) potentiates the serum gonadotropin-II (GtH-II) response to gonadotropin-releasing hormone (GnRH) without affecting basal GtH-II levels. Since the release of GtH-II in goldfish is under a tonic dopaminergic inhibitory tone, the possibility of sex steroids modulating brain and pituitary dopamine was examined in vivo and in vitro. Implantation of females with either T or E 2 (100 μg/g in solid silastic pellets) also potentiated the increase in serum GtH-II in response to the dopamine antagonist, domperidone (10 μg/g). High-performance liquid chromatography measurements showed that steroid implantation had no effect on dopamine content in the telencephalon including preoptic area, hypothalamus, and pituitary. However, the present study demonstrates that T or E 2 can increase pituitary dopamine turnover rates following tyrosine hydroxylase inhibition with α-methyl-p-tyrosine (240 μg/g). In vitro perifusion of pars distalis fragments from E 2- or T-treated fish also showed a potentiation of salmon GnRH (sGnRH)-induced GtH-II release compared to controls. However, exposure to pituitary fragments from control and steroid-treated fish to increasing doses of the dopamine agonist LY 171555 did not demonstrate a significant difference in the sensitivity of the gonadotrophs to dopamine. Testosterone- induced alterations in DA turnover are dissociable from the positive action of T on pituitary responsiveness, since the potentiating effect of T implantation was not affected by severe depletion of brain and pituitary DA levels by α-methyl-p-tyrosine pretreatment. These data demonstrate that in gonad-intact goldfish, sex steroids enhance pituitary responsiveness to GnRH but basal serum GtH-II levels are maintained by a concomitant increase in DA turnover in the pituitary. | en_US |
dc.language | eng | en_US |
dc.publisher | Academic Press. The Journal's web site is located at http://www.elsevier.com/locate/ygcen | en_US |
dc.relation.ispartof | General and Comparative Endocrinology | en_US |
dc.subject.mesh | Animals | en_US |
dc.subject.mesh | Brain - Drug Effects - Metabolism | en_US |
dc.subject.mesh | Chromatography, High Pressure Liquid | en_US |
dc.subject.mesh | Domperidone - Pharmacology | en_US |
dc.subject.mesh | Dopamine - Metabolism | en_US |
dc.subject.mesh | Drug Implants | en_US |
dc.subject.mesh | Estradiol - Pharmacology | en_US |
dc.subject.mesh | Female | en_US |
dc.subject.mesh | Goldfish - Physiology | en_US |
dc.subject.mesh | Gonadotropin-Releasing Hormone - Analogs & Derivatives - Pharmacology | en_US |
dc.subject.mesh | Gonadotropins, Pituitary - Secretion | en_US |
dc.subject.mesh | Peritoneal Cavity | en_US |
dc.subject.mesh | Pituitary Gland - Drug Effects - Metabolism | en_US |
dc.subject.mesh | Telencephalon - Drug Effects - Metabolism | en_US |
dc.subject.mesh | Testosterone - Pharmacology | en_US |
dc.subject.mesh | Tyrosine 3-Monooxygenase - Antagonists & Inhibitors | en_US |
dc.title | Interactions of gonadal steroids with brain dopamine and gonadotropin- releasing hormone in the control of gonadotropin-II secretion in the goldfish | en_US |
dc.type | Article | en_US |
dc.identifier.email | Wong, AOL: olwong@hkucc.hku.hk | en_US |
dc.identifier.authority | Wong, AOL=rp00806 | en_US |
dc.description.nature | link_to_subscribed_fulltext | en_US |
dc.identifier.doi | 10.1006/gcen.1993.1007 | en_US |
dc.identifier.pmid | 8094059 | - |
dc.identifier.scopus | eid_2-s2.0-0027470681 | en_US |
dc.identifier.volume | 89 | en_US |
dc.identifier.issue | 1 | en_US |
dc.identifier.spage | 39 | en_US |
dc.identifier.epage | 50 | en_US |
dc.identifier.isi | WOS:A1993KW63000006 | - |
dc.publisher.place | United States | en_US |
dc.identifier.scopusauthorid | Trudeau, VL=7006634572 | en_US |
dc.identifier.scopusauthorid | Sloley, BD=7003269861 | en_US |
dc.identifier.scopusauthorid | Wong, AOL=7403147570 | en_US |
dc.identifier.scopusauthorid | Peter, RE=7202909690 | en_US |
dc.identifier.issnl | 0016-6480 | - |