Inhibition of parathyroid hormone release by maitotoxin, a calcium channel activator
Journal Article
·
· Endocrinology; (United States)
Maitotoxin, a toxin derived from a marine dinoflagellate, is a potent activator of voltage-sensitive calcium channels. To further test the hypothesis that inhibition of PTH secretion by calcium is mediated via a calcium channel we studied the effect of maitotoxin on dispersed bovine parathyroid cells. Maitotoxin inhibited PTH release in a dose-dependent fashion, and inhibition was maximal at 1 ng/ml. Chelation of extracellular calcium by EGTA blocked the inhibition of PTH by maitotoxin. Maitotoxin enhanced the effects of the dihydropyridine calcium channel agonist (+)202-791 and increased the rate of radiocalcium uptake in parathyroid cells. Pertussis toxin, which ADP-ribosylates and inactivates a guanine nucleotide regulatory protein that interacts with calcium channels in the parathyroid cell, did not affect the inhibition of PTH secretion by maitotoxin. Maitotoxin, by its action on calcium channels allows entry of extracellular calcium and inhibits PTH release. Our results suggest that calcium channels are involved in the release of PTH. Inhibition of PTH release by maitotoxin is not sensitive to pertussis toxin, suggesting that maitotoxin may act distal to the site interacting with a guanine nucleotide regulatory protein, or maitotoxin could interact with other ions or second messengers to inhibit PTH release.
- Research Organization:
- Univ. of Texas Health Science Center, San Antonio (USA)
- OSTI ID:
- 6569423
- Journal Information:
- Endocrinology; (United States), Journal Name: Endocrinology; (United States) Vol. 124:1; ISSN ENDOA
- Country of Publication:
- United States
- Language:
- English
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Platelet cytosolic 44-kDa protein is a substrate of cholera toxin-induced ADP-ribosylation and is not recognized by antisera against the. alpha. subunit of the stimulatory guanine nucleotide-binding regulatory protein
Journal Article
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Sat Mar 31 23:00:00 EST 1990
· Endocrinology; (USA)
·
OSTI ID:6897245
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Journal Article
·
Sun Oct 01 00:00:00 EDT 1989
· Toxicology and Applied Pharmacology; (USA)
·
OSTI ID:5264714
Platelet cytosolic 44-kDa protein is a substrate of cholera toxin-induced ADP-ribosylation and is not recognized by antisera against the. alpha. subunit of the stimulatory guanine nucleotide-binding regulatory protein
Journal Article
·
Mon Aug 01 00:00:00 EDT 1988
· Proceedings of the National Academy of Sciences of the United States of America; (USA)
·
OSTI ID:5641944
Related Subjects
550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALCOHOLS
ALKALINE EARTH ISOTOPES
ALKALINE EARTH METALS
ANIMALS
ANTIGENS
BIOLOGICAL EFFECTS
BODY
CALCIUM
CALCIUM ISOTOPES
CARBOXYLIC ACIDS
CATTLE
CHELATING AGENTS
DOMESTIC ANIMALS
DOSE-RESPONSE RELATIONSHIPS
EGTA
ELEMENTS
ENDOCRINE GLANDS
GLANDS
GLYCOLS
HORMONES
HYDROXY COMPOUNDS
INHIBITION
ISOTOPES
MAMMALS
MATERIALS
METALS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
PARATHORMONE
PARATHYROID GLANDS
PEPTIDE HORMONES
RUMINANTS
SECRETION
TOXIC MATERIALS
TOXINS
VERTEBRATES
59 BASIC BIOLOGICAL SCIENCES
ALCOHOLS
ALKALINE EARTH ISOTOPES
ALKALINE EARTH METALS
ANIMALS
ANTIGENS
BIOLOGICAL EFFECTS
BODY
CALCIUM
CALCIUM ISOTOPES
CARBOXYLIC ACIDS
CATTLE
CHELATING AGENTS
DOMESTIC ANIMALS
DOSE-RESPONSE RELATIONSHIPS
EGTA
ELEMENTS
ENDOCRINE GLANDS
GLANDS
GLYCOLS
HORMONES
HYDROXY COMPOUNDS
INHIBITION
ISOTOPES
MAMMALS
MATERIALS
METALS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
PARATHORMONE
PARATHYROID GLANDS
PEPTIDE HORMONES
RUMINANTS
SECRETION
TOXIC MATERIALS
TOXINS
VERTEBRATES