Document Detail


Cysteamine inhibition of bovine pituitary secretory granule prolactin immunoassayability and release.
MedLine Citation:
PMID:  6745176     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Cysteamine [2-mercaptoethylamine (CySH)] displays a variety of neuroendocrine effects, the most potent being the depletion of immunoassayable tissue PRL. The present study used bovine adenohypophysial secretory granules to characterize this inhibition of measurable hormone (assayability). CySH decreased assayability in a dose-dependent manner at pH 7.4, with 50% inhibition observed close to 2 mM. Maximal inhibition was found between pH 6.0 and 6.5, whereas diminished (or no) inhibition occurred under alkaline conditions, depending on the buffer. In contrast, reduced glutathione (without CySH) increased assayability at pH 8-8.5, had little potency near neutrality, and inhibited assayability under acidic conditions. Electrophoretic studies under nondenaturing conditions demonstrated that CySH exposure of standard PRL resulted in additional charged species. With granules, CySH markedly decreased the staining of the major PRL band, no new bands were evident, and this effect was abolished by glutathione. Sodium dodecyl sulfate-electrophoretic patterns indicated that CySH resulted in higher apparent mol wt species of granule and standard PRL. This effect was nullified by mercaptoethanol. Never was there evidence for species smaller than monomeric. Depletion of PRL might involve interference with the conversion from oligomeric storage PRL to assayable PRL; 44-fold increases in PRL oligomer immunoactivity after alkali and thiol treatment were reduced to 6-fold increases when CySH was present. Reactions involved in production of assayable hormone appear relevant to secretion, since CySH also inhibited PRL release from granules, with maximal inhibition occurring under acidic conditions. Thus, CySH may be useful in investigating the physicochemical properties of tissue PRL and may also represent an approach to treatment of hyperprolactinemic states.
Authors:
M Y Lorenson
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Endocrinology     Volume:  115     ISSN:  0013-7227     ISO Abbreviation:  Endocrinology     Publication Date:  1984 Aug 
Date Detail:
Created Date:  1984-09-05     Completed Date:  1984-09-05     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0375040     Medline TA:  Endocrinology     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  728-35     Citation Subset:  AIM; IM    
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MeSH Terms
Descriptor/Qualifier:
Animals
Cattle
Cysteamine / pharmacology*
Cytoplasmic Granules / metabolism*
Electrophoresis, Polyacrylamide Gel
Glutathione / pharmacology
Hydrogen-Ion Concentration
Oxidation-Reduction
Pituitary Gland / metabolism*,  ultrastructure
Prolactin / antagonists & inhibitors*,  metabolism*
Radioimmunoassay
Grant Support
ID/Acronym/Agency:
AM-21783/AM/NIADDK NIH HHS; AM-31326/AM/NIADDK NIH HHS; RR-00044/RR/NCRR NIH HHS
Chemical
Reg. No./Substance:
60-23-1/Cysteamine; 70-18-8/Glutathione; 9002-62-4/Prolactin

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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