Synthesis, internalization, and localization of atrial natriuretic peptide in rat adrenal medulla
Some, though not all studies, have indicated that atrial natriuretic peptide (ANP) can bind to adrenal medullary cells. ANP-like immunoreactivity (ANP-LI) has also been identified in catecholamine-secreting cells. Together, these findings suggest that ANP may be taken up and/or synthesized in the adrenal medulla. The present study was designed to ascertain, by in situ hybridization, whether adrenal chromaffin cells could synthesize ANP, to define by an in vivo ultrastructural autoradiographic approach, whether ANP could, in fact, bind to rat adrenal medulla cells, to determine whether there was a cellular (noradrenaline (NA) vs. adrenaline (A)) selectivity in the binding process, and to establish whether extracellular (125I)ANP could be internalized by these cells. The cellular and subcellular distribution of endogenous ANP-LI was also investigated in both cell types by cryoultramicrotomy and immunocytochemical approaches. The in situ hybridization studies indicate the presence of mRNA to ANP in about 15% of adrenal medullary cells. Intravenous injection of (125I)ANP resulted in a 3-fold, preferential and specific radiolabeling of A-as compared to NA-containing cells. In A-containing cells, plasma membranes were significantly labeled 2 and 5 min post injection; cytoplasmic matrix, mitochondria, and secretory granules throughout the time course studied (1-30 min post injection). Lysosomes, rough endoplasmic reticulum, Golgi apparatus, and nuclei were not labeled. ANP-LI was identified in both NA- and A-containing cells; in the former, it was almost exclusively localized in secretory vesicles, in the latter it was detected in plasma membranes, cytoplasmic matrix, nuclear euchromatin, some mitochondria and relatively fewer granules than in NA-containing cells.
- Research Organization:
- CNRS UA 559, Faculte de Medecine Lyon-Sud, Oullins (France)
- OSTI ID:
- 6954457
- Journal Information:
- Endocrinology; (United States), Vol. 123:1
- Country of Publication:
- United States
- Language:
- English
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PEPTIDES
BIOSYNTHESIS
AUTORADIOGRAPHY
BIOCHEMICAL REACTION KINETICS
CELL MEMBRANES
CYTOPLASM
HYBRIDIZATION
IODINE 125
MITOCHONDRIA
RATS
SUBCELLULAR DISTRIBUTION
ANIMALS
BETA DECAY RADIOISOTOPES
CELL CONSTITUENTS
DAYS LIVING RADIOISOTOPES
DISTRIBUTION
ELECTRON CAPTURE RADIOISOTOPES
INTERMEDIATE MASS NUCLEI
IODINE ISOTOPES
ISOTOPES
KINETICS
MAMMALS
MEMBRANES
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANOIDS
PROTEINS
RADIOISOTOPES
REACTION KINETICS
RODENTS
SYNTHESIS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques