Mineralocorticoid specificity of renal type I receptors: in vivo binding studies
The authors have injected rats with (TH)aldosterone or (TH) corticosterone, plus 100-fold excess of the highly specific glucocorticoid RU 28362, with or without excess unlabeled aldosterone or corticosterone and compared type I receptor occupancy in kidney and hippocampus. Thirty minutes after subcutaneous injection (TH)aldosterone was well retained in renal papilla-inner medulla, renal cortex-outer medulla, and hippocampus; in contrast, (TH)corticosterone was well retained only in hippocampus. Competition studies for (TH)aldosterone binding sites showed corticosterone to be a poor competitor in the kidney compared with hippocampus. Time-course studies, with rats killed 10-180 min after tracer administration, showed very low uptake/retention of (TH)corticosterone by kidney; in hippocampus (TH)corticosterone retention was similar to that of (TH)aldosterone in kidney, and retention of (TH)aldosterone by hippocampus was much more prolonged than of either tracer in any other tissue. Studies in 10-day-old rats, with very low levels of corticosteroid binding globulin (CBG), showed a high degree of aldosterone selectivity in both zones of the kidney, whereas 9TH)aldosterone and (TH)corticosterone were equivalently bound in hippocampus. They interpret these data as evidenced for a mechanism unrelated to extravascular CBG conferring mineralocorticoid specificity on renal type I receptors and propose two models derived from their findings consistent with such differential selectivity.
- Research Organization:
- Prince Henry's Hospital, Victoria, Australia
- OSTI ID:
- 6284330
- Journal Information:
- Am. J. Physiol.; (United States), Vol. 252:2
- Country of Publication:
- United States
- Language:
- English
Similar Records
Profile of the intestinal mucosal corticosteroid receptors in the domestic duck
Activation of the rat kidney mineralocorticoid receptor
Related Subjects
GLUCOCORTICOIDS
TISSUE DISTRIBUTION
TRITIUM COMPOUNDS
ALDOSTERONE
CORTICOSTERONE
HIPPOCAMPUS
IN VIVO
KIDNEYS
LIQUID COLUMN CHROMATOGRAPHY
RATS
RETENTION
ADRENAL HORMONES
ALDEHYDES
ANIMALS
BODY
BRAIN
CENTRAL NERVOUS SYSTEM
CHROMATOGRAPHY
CORTICOSTEROIDS
DISTRIBUTION
HORMONES
HYDROXY COMPOUNDS
KETONES
LABELLED COMPOUNDS
MAMMALS
MINERALOCORTICOIDS
NERVOUS SYSTEM
ORGANIC COMPOUNDS
ORGANS
PREGNANES
RODENTS
SEPARATION PROCESSES
STEROID HORMONES
STEROIDS
VERTEBRATES
550501* - Metabolism- Tracer Techniques