Autoradiographic evidence of nuclear binding of spironolactone in rabbit cortical collecting tubule

Journal Article · Tue Jan 01 04:00:00 EST 1991 · Endocrinology; (USA)

DOI:https://doi.org/10.1210/endo-128-1-280· OSTI ID:6215454

Bonvalet, J P; Blot-Chabaud, M; Farman, N ^[1]

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1. CEN Saclay, Gif-Yvette (France)

Previous biochemical studies indicated that the spirolactone-mineralocorticoid receptor complexes are unable to translocate into the nucleus. The present study was designed to reinvestigate the intracellular distribution of spirolactone-binding sites, using autoradiography. For this purpose, rabbit kidney pyramids were incubated at 30 C with tritiated SC9420 or aldosterone. Thereafter, aldosterone-sensitive cortical collecting tubules were microdissected and processed for dry film autoradiography. The concentration was 2 nM for both steroids. Non-specific labeling was determined by incubations with tritiated steroids plus a 100-fold excess of unlabeled steroids. Results show the presence of specific nuclear labeling for both ({sup 3}H) aldosterone and ({sup 3}H)SC9420. Specific cytoplasmic labeling was very low for both ({sup 3}H)aldosterone and ({sup 3}H)SC9420. The nuclear labeling by ({sup 3}H)SC9420 was equally and almost completely displaced by a 100-fold excess of unlabeled aldosterone or SC9420 (91% and 87%, respectively). We conclude that spironolactone-receptor complexes migrate into the nucleus. The difference between these results and those of previous studies with biochemical techniques, which failed to detect specific nuclear binding of spirolactone, may be due to methodological reasons.

• OSTI ID: 6215454
• Journal Information: Endocrinology; (USA), Journal Name: Endocrinology; (USA) Vol. 128:1; ISSN ENDOA; ISSN 0013-7227
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ADRENAL HORMONES
ALDEHYDES
ALDOSTERONE
AUTORADIOGRAPHY
BIOCHEMICAL REACTION KINETICS
BODY
CELL CONSTITUENTS
CELL NUCLEI
COMPLEXES
CORTICOSTEROIDS
CYTOPLASM
DISTRIBUTION
GLUCOCORTICOIDS
HYDROGEN COMPOUNDS
HYDROXY COMPOUNDS
KETONES
KIDNEYS
KINETICS
MEMBRANE PROTEINS
MINERALOCORTICOIDS
ORGANIC COMPOUNDS
ORGANS
PREGNANES
PROTEINS
REACTION KINETICS
RECEPTORS
STEROIDS
SUBCELLULAR DISTRIBUTION
TRITIUM COMPOUNDS
TUBULES