The effects of corticotrophin-releasing hormone, arginine vasopressin and their antagonists on ACTH release from perifused horse anterior pituitary cells.
Abstract: Antagonists are useful for probing hormone action and receptor characteristics. In this study we have investigated the inhibitory effects of analogues of arginine vasopressin (AVP) and corticotrophin-releasing hormone (CRH) on stimulated release of immunoreactive ACTH from perifused equine anterior pituitary cells in vitro. Our aims were to gain some insight into the characteristics of the CRH and AVP receptors of the horse pituitary and to establish whether the response induced by AVP and CRH together could be blocked by combining antagonists. Experimental design included 5-min pulses of AVP (12.5 nmol/l), CRH (0.3 nmol/l) or CRH plus AVP given every 40 min alternately with pulses of secretagogue(s) plus appropriate antagonist(s). The effect of combined antagonists on the response to lower secretagogue concentrations (CRH, 0.03 nmol/l plus AVP, 2.5 nmol/l) was also tested. Response in the presence of an antagonist was compared with the mean response to secretagogue in the immediately preceding and following pulse and was expressed as per cent expected ACTH. The ACTH response to AVP was inhibited over the dose range 0.4-50 mumol/l by Phaa-D-Tyr(Et)2Lys6Arg3VP (P < 0.002; ANOVA) and by d(CH2)5[Tyr(Me)2]AVP (P < 0.001). Suppression of the expected ACTH response to AVP by these two antagonists was most effectively achieved by antagonist concentrations of 10 mumol/l (to 28 +/- 2.1%) and 25 mumol/l (to 22 +/- 5.1%) respectively. Inhibition was not improved by preinfusion compared with a bolus pulse. Aaa-D-Try(Et)2Val4Abu6Arg8.9VP and the non-peptide antagonist OPC-21268 had no inhibitory effect.(ABSTRACT TRUNCATED AT 250 WORDS)
Publication Date: 1994-10-01 PubMed ID: 7964325DOI: 10.1677/joe.0.1430085Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.
This study investigates the inhibitory impacts of arginine vasopressin and corticotrophin-releasing hormone on the release of ACTH from horse pituitary cells. The main goal of the research was to gain more understanding of the CRH and AVP receptors in the horse pituitary and to determine if their combination could be blocked by antagonists.
Research Aims
- The central focus of this research revolves around understanding the role of Corticotropin-Releasing Hormone (CRH) and Arginine Vasopressin (AVP) in the regulated release of Adrenocorticotropic hormone (ACTH) in horses’ anterior pituitary cells.
- The study aimed to understand more about the character of the CRH and AVP receptors of the horse pituitary gland.
- The researchers intend to find out whether the responses induced simultaneously by AVP and CRH could be obstructed by employing antagonists.
Methodology
- The research involved a series of tests which involved applying pulse pulses of AVP, CRH, or a combination of both in intervals of 40 minutes.
- The pulses were given alternatingly with pulses that contained the secretagogues as well as the respective antagonist.
- In order to understand the effects of combined antagonists, the response to diminished secretagogue concentrations was tested (CRH, 0.03 nmol/l plus AVP, 2.5 nmol/l).
Findings and Conclusion
- Notably, the ACTH response to AVP was effectively inhibited over the dose range from 0.4-50 mumol/l by two antagonists, namely Phaa-D-Tyr(Et)2Lys6Arg3VP and d(CH2)5[Tyr(Me)2]AVP.
- The most effective suppression of the anticipated ACTH response to AVP was noted when the concentration of the antagonists were such: 10 mumol/l (to 28 +/- 2.1%) and 25 mumol/l (to 22 +/- 5.1%) respectively.
- Other salient findings found that the inhibition was not improved by pre-infusion compared to a bolus pulse. The antagonist Aaa-D-Try (Et)2Val4Abu6Arg8.9VP and non-peptide antagonist OPC-21268 yielded no inhibitory activity.
- The truncated abstract does not provide a full conclusion, but does highlight the potential effectiveness of certain antagonists in altering ACTH responses instigated by AVP and CRH within the context of horse pituitary cells.
Cite This Article
APA
Ellis MJ, Mulligan RS, Evans MJ, Donald RA.
(1994).
The effects of corticotrophin-releasing hormone, arginine vasopressin and their antagonists on ACTH release from perifused horse anterior pituitary cells.
J Endocrinol, 143(1), 85-93.
https://doi.org/10.1677/joe.0.1430085 Publication
Researcher Affiliations
- Department of Endocrinology, Christchurch Hospital, New Zealand.
MeSH Terms
- Adrenocorticotropic Hormone / metabolism
- Animals
- Arginine Vasopressin / analogs & derivatives
- Arginine Vasopressin / antagonists & inhibitors
- Arginine Vasopressin / pharmacology
- Biological Assay
- Cells, Cultured
- Corticotropin-Releasing Hormone / antagonists & inhibitors
- Corticotropin-Releasing Hormone / pharmacology
- Dose-Response Relationship, Drug
- Drug Synergism
- Female
- Horses / physiology
- Male
- Piperidines / pharmacology
- Pituitary Gland, Anterior / cytology
- Pituitary Gland, Anterior / metabolism
- Quinolones / pharmacology
Citations
This article has been cited 2 times.- Zhu Z, Cui W, Zhu D, Gao N, Zhu Y. Common tools for pituitary adenomas research: cell lines and primary cells.. Pituitary 2020 Apr;23(2):182-188.
- O'Connor SJ, Gardner DS, Ousey JC, Holdstock N, Rossdale P, Edwards CM, Fowden AL, Giussani DA. Development of baroreflex and endocrine responses to hypotensive stress in newborn foals and lambs.. Pflugers Arch 2005 Aug;450(5):298-306.
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