Comparison of the secretory mechanisms of meta-iodobenzyl-guanidine (MIBG) and norepinephrine (NE) from cultured bovine adrenomedullary cells
Using cultured bovine adrenomedullary cells, the authors compared the secretary mechanisms of preloaded I-125-MIBG and H-3-NE. Acetylcholine (ACh) stimulated the secretion of MIBG and NE in a time-dependent manner. At 10 min, 100 ..mu..M ACh stimulated secretion was 19.6 +- 2.9% for MIBG and 25.5 +- 1.6% for NE. Basal or unstimulated secretion was 8.6 +- 1.2% for MIBG and 7.2 +- 1.6% for NE. The ED-50 for ACh stimulated secretion was 20 ..mu..M for MIBG and 10 ..mu..M for NE. The maximal secretion of MIBG NE was obtained with 32 ..mu..M and 100 ..mu..M ACh, respectively. The ACh stimulated secretion of both MIBG and NE was calcium-dependent. The calcium ionophore A23187 stimulated the secretion of MIBG and NE in a time-dependent manner. At 20 min, 10 ..mu..M A23187 stimulated secretion was 15.4 +- 1.1% for MIBG and 15.1 +- 0.4% for NE. The sodium ionophor veratridine also stimulated the secretion of MIBG and NE in a time-dependent manner. At 20 min, 100 ..mu..M veratridine stimulated secretion was 25.8 +- 2.5% for MIBG and 35.6 +- 0.7% for NE. Elevated potassium, 56 mM, stimulated the secretion of MIBG and NE; at 2 mink secretion was 13.4 +- 0.4% for MIBG and 17.8 +- 0.9% for NE. These studies demonstrate similar ionic requirements and receptor interaction for the secretion of MIBG and NE. Although some differences appear to exist in the relative cellular compartmentation of MIBG and NE, these results suggest that I-131-MIBG scintigraphy reflects granular storage. Loss of target tissue I-131-MIBG say, therefore, reflect granular mediated release.
- Research Organization:
- Univ. of Michigan Medical Center, Ann Arbor, MI
- OSTI ID:
- 6645118
- Report Number(s):
- CONF-850611-
- Journal Information:
- J. Nucl. Med.; (United States), Vol. 26:5; Conference: 32. annual meeting of the Society of Nuclear Medicine, Houston, TX, USA, 2 Jun 1985
- Country of Publication:
- United States
- Language:
- English
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MEMBRANE PORES
BIOCHEMICAL REACTION KINETICS
MIBG
MEMBRANE TRANSPORT
NORADRENALINE
SECRETION
RECEPTORS
ACETYLCHOLINE
ADRENAL GLANDS
BIOCHEMISTRY
CATTLE
CELL CULTURES
ELECTROPHYSIOLOGY
IODINE 125
IODINE 131
METABOLISM
RADIONUCLIDE KINETICS
RADIORECEPTOR ASSAY
TRACER TECHNIQUES
TRITIUM COMPOUNDS
ADRENAL HORMONES
AMINES
AMMONIUM COMPOUNDS
ANIMALS
AUTONOMIC NERVOUS SYSTEM AGENTS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
CARDIOTONICS
CARDIOVASCULAR AGENTS
CHEMISTRY
DAYS LIVING RADIOISOTOPES
DOMESTIC ANIMALS
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
ENDOCRINE GLANDS
ESTERS
GLANDS
HORMONES
INTERMEDIATE MASS NUCLEI
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LABELLED COMPOUNDS
MAMMALS
MEMBRANE PROTEINS
NEUROREGULATORS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANS
PARASYMPATHOMIMETICS
PHYSIOLOGY
PROTEINS
QUATERNARY COMPOUNDS
RADIOISOTOPES
RADIOPHARMACEUTICALS
REACTION KINETICS
RUMINANTS
STEROID HORMONES
SYMPATHOMIMETICS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques
550501 - Metabolism- Tracer Techniques
550301 - Cytology- Tracer Techniques