Circadian variation of β-adrenoceptor binding sites in the pineal gland of the Syrian hamster and prevention of the nocturnal reduction by light exposure or propranolol treatment

B. Pangerl, A. Pangerl, R. J. Reiter, D. J. Jones

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13 Scopus citations


Radioreceptor assays with (-)[125I]-iodopindolol (IPIN) were used to describe circadian variations of β-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 < 0.01) with maximal values (28.9 ± 1.8 fmol/mg protein, x̄ ± 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 β-adrenergic receptor blocker, propranolol, prevented the nocturnal drop in the number of β-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.

Original languageEnglish (US)
Pages (from-to)570-573
Number of pages4
Issue number6
Publication statusPublished - Jan 1 1989


ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Endocrinology
  • Endocrine and Autonomic Systems
  • Cellular and Molecular Neuroscience

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