Mechanism of action of cysteamine in depleting prolactin immunoreactivity

Journal Article · Thu Aug 01 04:00:00 EDT 1985 · Endocrinology; (United States)

DOI:https://doi.org/10.1210/endo-117-2-591· OSTI ID:6181149

Sagar, S M; Millard, W J; Martin, J B; Murchison, S C

The thiol reagent cysteamine (CSH) depletes anterior pituitary cells of immunoreactive PRL both in vivo and in vitro. The authors examined the hypothesis that CSH affects either the solubility or immunoreactivity of PRL through a mechanism involving thiol-disulfide exchange. Adult female rats were treated with either CSH (300 mg/kg, sc) or an equimolar dose of ethanolamine as a control. Anterior pituitary glands were extracted in 0.1 M sodium borate buffer, pH 9.0. Treatment of pituitary extracts with beta-mercaptoethanol (BME) destroys the immunoreactivity of PRL. However, extraction in the presence of reduced glutathione or CSH of pituitaries of rats treated with CSH restores immunoreactive PRL to control levels. Extracts were also subjected to polyacrylamide gel electrophoresis (PAGE). On gels of pituitary extracts of CSH-treated rats, the band that comigrates with purified PRL is diminished compared to that in ethanolamine-treated controls. However, extraction of the pituitaries in sodium dodecyl sulfate-containing buffer followed by chemical reduction with BME restores the PRL band. Therefore, CSH acts on PRL through a thiol-related mechanism to yield a product that is poorly soluble in aqueous buffer at pH 9 and is poorly immunoreactive. Dispersed anterior pituitary cells in tissue culture were incubated with L-(TVS)methionine to radiolabel newly synthesized peptides. PAGE followed by autoradiography confirmed the above results obtained in vivo.

• Research Organization: Massachusetts General Hospital, Boston
• OSTI ID: 6181149
• Journal Information: Endocrinology; (United States), Journal Name: Endocrinology; (United States) Vol. 2; ISSN ENDOA
• Country of Publication: United States
• Language: English

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550601* -- Medicine-- Unsealed Radionuclides in Diagnostics
62 RADIOLOGY AND NUCLEAR MEDICINE
AMINES
AMINO ACIDS
ANIMALS
AUTORADIOGRAPHY
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL EFFECTS
BODY
CARBOXYLIC ACIDS
CHELATING AGENTS
DAYS LIVING RADIOISOTOPES
DRUGS
EDTA
ENDOCRINE GLANDS
EVEN-ODD NUCLEI
GLANDS
GLUTATHIONE
GONADOTROPINS
HORMONES
IMMUNOLOGY
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
LIPOTROPIC FACTORS
LTH
MAMMALS
MEA
METHIONINE
NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
ORGANS
PEPTIDE HORMONES
PEPTIDES
PITUITARY GLAND
PITUITARY HORMONES
POLYPEPTIDES
PROTEINS
RADIOASSAY
RADIOIMMUNOASSAY
RADIOIMMUNOLOGY
RADIOISOTOPES
RADIOPROTECTIVE SUBSTANCES
RATS
RODENTS
SULFUR 35
SULFUR ISOTOPES
THIOLS
TRACER TECHNIQUES
VERTEBRATES