Picomolar-affinity binding and inhibition of adenylate cyclase activity by melatonin in Syrian hamster hypothalamus

Journal Article · Sat Dec 01 00:00:00 EST 1990 · Cellular and Molecular Neurobiology; (USA)

DOI:https://doi.org/10.1007/BF00712848· OSTI ID:5639742

Niles, L P; Hashemi, F ^[1]

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1. McMaster Univ.,Hamilton, ON (Canada)

1. The effect of melatonin on forskolin-stimulated adenylate cyclase activity was measured in homogenates of Syrian hamster hypothalamus. In addition, the saturation binding characteristics of the melatonin receptor ligand, ({sup 125}I)iodomelatonin, was examined using an incubation temperature (30{degree}C) similar to that used in enzyme assays. 2. At concentrations ranging from 10 pM to 1 nM, melatonin caused a significant decrease in stimulated adenylate cyclase activity with a maximum inhibition of approximately 22%. 3. Binding experiments utilizing ({sup 125}I)iodomelatonin in a range of approximately 5-80 pM indicated a single class of high-affinity sites: Kd = 55 +/- 9 pM, Bmax = 1.1 +/- 0.3 fmol/mg protein. 4. The ability of picomolar concentrations of melatonin to inhibit forskolin-stimulated adenylate cyclase activity suggests that this affect is mediated by picomolar-affinity receptor binding sites for this hormone in the hypothalamus.

• OSTI ID: 5639742
• Journal Information: Cellular and Molecular Neurobiology; (USA), Vol. 10:4; ISSN 0272-4340
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
CYCLASES
ENZYME ACTIVITY
MELATONIN
BIOCHEMICAL REACTION KINETICS
AFFINITY
HAMSTERS
HYPOTHALAMUS
INHIBITION
IODINE 125
LIGANDS
RADIOASSAY
RECEPTORS
TRACER TECHNIQUES
AMINES
ANIMALS
AROMATICS
AZAARENES
AZOLES
BETA DECAY RADIOISOTOPES
BODY
BRAIN
CENTRAL NERVOUS SYSTEM
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
ENZYMES
HETEROCYCLIC COMPOUNDS
INDOLES
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LYASES
MAMMALS
MEMBRANE PROTEINS
NERVOUS SYSTEM
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
PROTEINS
PYRROLES
RADIOISOTOPES
REACTION KINETICS
RODENTS
TRYPTAMINES
VERTEBRATES
550201* - Biochemistry- Tracer Techniques