Circadian variation of beta-adrenoceptor binding sites in the pineal gland of the Syrian hamster and prevention of the nocturnal reduction by light exposure or propranolol treatment
| Autor: | David J. Jones, Brigitte Pangerl, Andreas Pangerl, Russel J. Reiter |
|---|---|
| Rok vydání: | 1989 |
| Předmět: |
Male
endocrine system medicine.medical_specialty Light Endocrinology Diabetes and Metabolism Hamster Propranolol Nocturnal Pineal Gland Cellular and Molecular Neuroscience Pineal gland Endocrinology Internal medicine Cricetinae parasitic diseases Receptors Adrenergic beta medicine Animals Circadian rhythm Binding site Binding Sites biology Mesocricetus Endocrine and Autonomic Systems biology.organism_classification Circadian Rhythm medicine.anatomical_structure Endocrine gland medicine.drug |
| Zdroj: | Neuroendocrinology. 49(6) |
| ISSN: | 0028-3835 |
| Popis: | Radioreceptor assays with (-) [125I]-iodopindolol (IPIN) were used to describe circadian variations of beta-adrenoceptors in the pineal gland of male Syrian hamsters (Mesocricetus auratus). Single-point experiments (200 pM IPIN, 8-9 pineals pooled per time point) showed a significant circadian variation (p less than 0.01) with maximal values (28.9 +/- 1.8 fmol/mg protein, means +/- SEM, n = 7) between 07:00 and 02:30 h, and minimal values at 04:00 (7.2 +/- 2.9 fmol/mg protein, n = 3), 8 h after darkness onset. Either exposure of animals to light at night or treating dark exposed hamsters with a beta-adrenergic receptor blocker, propranolol, prevented the nocturnal drop in the number of beta-adrenoceptors. Scatchard analysis of saturation isotherms at 02:30, 04:00 and 08:00 h (30-600 pM IPIN, one saturation experiment with 25 pineals pooled per time point) confirmed the circadian variation. |
| Databáze: | OpenAIRE |
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