New sensitive serum melatonin radioimmunoassay employing the Kennaway G280 antibody: Syrian hamster morning adrenergic response

Vaughan, George M.

doi:10.1111/j.1600-079x.1993.tb00514.x

Cited by 77 publications

(50 citation statements)

References 53 publications

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“…The direct saliva Melatonin RIA from Bühlmann Laboratories AG, Switzerland, was used [17]. 125 -I melatonin was counted in a gamma-counter (Autogamma 5000 Cobra TM, Packard Instrument Co. Inc., Downers Grove, Ill., USA).…”

Section: Methodsmentioning

confidence: 99%

Emergence and Evolution of the Circadian Rhythm of Melatonin in Children

Ardura

Gutierrez²,

Andrés³

et al. 2003

Horm Res Paediatr

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Objective: To assess the age at which the circadian rhythm of melatonin begins. Methods: 55 children, divided into groups from the neonatal period to 24 months of life, were studied. Urine samples were taken from 28 newborn babies to measure 6-sulfatoxymelatonin (aMT6s). Salivary samples were collected from infants (27 cases), to measure melatonin (aMT). aMT was measured by RIA and aMT6s by ELISA using commercial kits. Changes in the levels of aMT6s and aMT were evaluated using the Friedman test and Wilcoxon matched pair test. Results: The group aged 27–41 days showed statistically significant differences in daily aMT6s and aMT concentrations. The highest values were always found between 24.00 and 8.00 h. This day/night difference persisted from 2–3 to 13–24 months of age. Conclusion: The data indicate that the circadian melatonin rhythm appears at the end of the neonatal period and persists thereafter.

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Section: Methodsmentioning

confidence: 99%

Emergence and Evolution of the Circadian Rhythm of Melatonin in Children

Ardura

Gutierrez²,

Andrés³

et al. 2003

Horm Res Paediatr

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“…Melatonin was measured by a double-antibody radioimmunoassay based on the Kennaway G280 anti-melatonin antibody. 25) For analysis of preneoplastic lesion development, numbers and areas of GST-P-positive foci of more than 0.2 mm in diameter were measured using a color video image processor (SPICCA II, Nippon Avionics Co., Ltd., Tokyo), and data per cm 2 of liver section were calculated. Statistical analysis was carried out using Student's t-or Welch's t-test after application of the preliminary F-test for equal variance.…”

Section: Methodsmentioning

confidence: 99%

The 1.5 GHz Electromagnetic Near‐field Used for Cellular Phones Does Not Promote Rat Liver Carcinogenesis in a Medium‐term Liver Bioassay

Imaida

Taki

Watanabe³

et al. 1998

Japanese Journal of Cancer Research

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We have recently established that local exposure to a 929.2 MHz electromagnetic near-field, used for cellular phones, does not promote rat liver carcinogenesis in a medium-term bioassay system. In the present study, a 1.439 GHz electromagnetic near-field (EMF), another microwave band employed for cellular phones in Japan, was similarly investigated. Time division multiple access (TDMA) signals for the Personal Digital Cellular (PDC) Japanese cellular telephone standard system were directed to rats through a quarter-wavelength monopole antenna. Numerical dosimetry showed that the peak SARs within the liver were 1.91-0.937 W/kg, while the whole-body average specific absorption rates (SARs) were 0.680-0.453 W/kg, when the time-averaged antenna radiation power was 0.33 W. Exposure was for 90 min a day, 5 days a week, over 6 weeks, to male F344 rats given a single dose of diethylnitrosamine (200 mg/kg, i.p.) 2 weeks previously. At week 3, all rats were subjected to a two-thirds partial hepatectomy. At week 8, the experiment was terminated and the animals were killed. Carcinogenic potential was scored by comparing the numbers and areas of the induced glutathione S-transferase placental form (GST-P)-positive foci in the livers of exposed (48) and sham-exposed rats (48). Despite increased serum levels of corticosterone, adrenocorticotropic hormone (ACTH) and melatonin, the numbers and the areas of GST-Ppositive foci were not significantly altered by the exposure. These findings clearly indicated that local body exposure to a 1.439 GHz EMF, as in the case of a 929.2 MHz field, has no promoting effect on rat liver carcinogenesis in the present model.

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“…Melatonin levels in pineal glands from male and female mice were determined by radioimmunoassay using the Buhlmann-saliva direct kit (ALPCO, Windham, NH), based on the Kennaway G280 melatonin antibody (40). Briefly, pineal glands were homogenized in assay buffer and spun at 12,000 rpm.…”

Section: Quantification Of Pineal Melatonin Levelsmentioning

confidence: 99%

Behavioral characterization and modulation of circadian rhythms by light and melatonin in C3H/HeN mice homozygous for the RORβ knockout

Masana¹,

Sumaya²,

Becker‐André³

et al. 2007

American Journal of Physiology-Regulatory, Integrative and Comp

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Masana MI, Sumaya IC, Becker-Andre M, Dubocovich ML. Behavioral characterization and modulation of circadian rhythms by light and melatonin in C3H/HeN mice homozygous for the ROR␤ knockout. Am J Physiol Regul Integr Comp Physiol 292: 2357-2367, 2007. First published February 15, 2007 doi:10.1152/ajpregu.00687.2006.-This study reports for the first time the effects of retinoid-related orphan receptors [ROR␤; receptor gene deletion ROR␤(C3H) Ϫ/Ϫ ] in C3H/ HeN mice on behavioral and circadian phenotypes. Pineal melatonin levels showed a robust diurnal rhythm with high levels at night in wild-type (ϩ/ϩ), heterozygous (ϩ/Ϫ), and knockout (Ϫ/Ϫ) mice. The ROR␤(C3H) Ϫ/Ϫ mice displayed motor ("duck gait," hind paw clasping reflex) and olfactory deficits, and reduced anxiety and learned helplessness-related behaviors. Circadian rhythms of wheelrunning activity in all genotypes showed entrainment to the light-dark (LD) cycle, and free running in constant dark, with ROR␤(C3H)mice showing a significant increase in circadian period (tau). Melatonin administration (90 g/mouse sc for 3 days) at circadian time (CT) 10 induced phase advances, while exposure to a light pulse (300 lux) at CT 14 induced phase delays of circadian activity rhythms of the same magnitude in all genotypes. In ROR␤(C3H) Ϫ/Ϫ mice a light pulse at CT 22 elicited a larger phase advance in activity rhythms and a slower rate of reentrainment after a 6-h advance in the LD cycle compared with (ϩ/ϩ) mice. Yet, the rate of reentrainment was significantly advanced by melatonin administration at the new dark onset in both (ϩ/ϩ) and (Ϫ/Ϫ) mice. We conclude that the ROR␤ nuclear receptor is not involved in either the rhythmic production of pineal melatonin or in mediating phase shifts of circadian rhythms by melatonin, but it may regulate clock responses to photic stimuli at certain time domains.retinoid-related orphan receptors ␤ gene; circadian activity rhythms; melatonin receptors; suprachiasmatic nucleus RETINOID-RELATED ORPHAN RECEPTORS (ROR) belong to a superfamily of nuclear hormone receptors comprising more than 40 transcription factors (7, 24). Members of this superfamily share a common modular structure consisting of a transactivation domain, a DNA-binding domain, and a ligand-binding domain (24). The family of ROR receptors is a subfamily of orphan receptors comprising ROR␣, ROR␤, and ROR␥ (21). ROR␤ is a nuclear receptor expressed in areas related to processing of sensory information, as well as circadian rhythmicity (27,33). Recently, structural data and structure-function analysis identified all-trans retinoic acid as a bona fide ligand for the ROR␤ nuclear receptor (37).Circadian oscillations of the mammalian biological clock within the suprachiasmatic nucleus (SCN) are driven by a main transcriptional/translational feedback loop of clock gene products. The negative arm of the loop involves the circadian oscillation of three period (Per) genes and two cryptochrome (Cry) genes, potent repressors of CLOCK/BAML1-induced transcription. The positive loop is...

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New sensitive serum melatonin radioimmunoassay employing the Kennaway G280 antibody: Syrian hamster morning adrenergic response

Cited by 77 publications

References 53 publications

Emergence and Evolution of the Circadian Rhythm of Melatonin in Children

Emergence and Evolution of the Circadian Rhythm of Melatonin in Children

The 1.5 GHz Electromagnetic Near‐field Used for Cellular Phones Does Not Promote Rat Liver Carcinogenesis in a Medium‐term Liver Bioassay

Behavioral characterization and modulation of circadian rhythms by light and melatonin in C3H/HeN mice homozygous for the RORβ knockout

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