Autoradiographic demonstration of oxytocin-binding sites in the macula densa
- Centre National de la Recherche Scientifique, Strasbourg (France)
Specific oxytocin (OT)-binding sites were localized in the rat kidney with use of a selective {sup 125}I-labeled OT antagonist ({sup 125}I-OTA). High concentrations of OT binding sites were detected on the juxtaglomerular apparatus with use of the conventional film autoradiographic technique. No labeling occurred on other renal structures. The cellular localization of the OT binding sites within the juxtaglomerular apparatus was studied in light microscope autoradiography, on semithin sections from paraformaldehyde-fixed kidney slices incubated in the presence of {sup 125}I-OTA. These preparations revealed selective labeling of the macula densa, mainly concentrated at the basal pole of the cells. Control experiments showed first that {sup 125}I-OTA binding characteristics were not noticeably altered by prior paraformaldehyde fixation of the kidneys and second that autoradiographic detection of the binding sites was not impaired by histological treatments following binding procedures. In view of the role of the macula densa in the tubuloglomerular feedback, the putative OT receptors of this structure might mediate the stimulatory effect of OT on glomerular filtration.
- OSTI ID:
- 5547261
- Journal Information:
- American Journal of Physiology; (USA), Journal Name: American Journal of Physiology; (USA) Vol. 257; ISSN 0002-9513; ISSN AJPHA
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
ANGIOTENSIN
ANIMALS
AUTORADIOGRAPHY
BETA DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL LOCALIZATION
BODY
CARDIOVASCULAR AGENTS
DAYS LIVING RADIOISOTOPES
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
GLOBULINS
HORMONES
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPES
KIDNEYS
KINETICS
MAMMALS
MEMBRANE PROTEINS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANS
OXYTOCIN
PEPTIDE HORMONES
PITUITARY HORMONES
PROTEINS
RADIOISOTOPES
RATS
REACTION KINETICS
RECEPTORS
RODENTS
VASOCONSTRICTORS
VERTEBRATES