Learn More
The mammalian Per1 gene is expressed in the suprachiasmatic nucleus of the hypothalamus, where it is thought to play a critical role in the generation of circadian rhythms. Per1 mRNA also is expressed in other tissues. Its expression in the pars tuberalis (PT) of the pituitary is noteworthy because, like the suprachiasmatic nucleus, it is a known site of(More)
We have isolated a novel variant of the Mel 1a melatonin receptor from an ovine PT cDNA library. Relative to the reported sequence for the Mel 1a melatonin receptor there are 8 changes in the DNA sequence. Only 3 of these result in amino acid substitutions, one in extracellular loop 3 and two in the carboxy-terminal tail. We have designated the novel(More)
A pre-requisite to understanding the physiological mechanisms of action of melatonin is the identification of the target sites where the hormone acts. The radioligand 2-[125I]iodo-melatonin has been used extensively to localize binding sites in both the brain and peripheral tissues. In general these binding sites have been found to be high affinity, with Kd(More)
Mammalian Per1 (or RIGUI) is a recently described putative clock gene that is expressed in the suprachiasmatic nucleus. It is also expressed in the pars tuberalis (PT) of the pituitary, where melatonin appears to drive its expression. This study examines the regulation of Per1 expression. In ovine PT cells, oPer1 is an early response gene transiently(More)
The purpose of this study was to determine whether the cells of the ovine pars tuberalis (PT) secrete a factor(s) that can influence the activity of cells in the pars distalis (PD). By Northern blotting of total RNA isolated from PD cells that had been stimulated in the presence of cycloheximide (10 micrograms/ml), PT cell-conditioned medium was shown to(More)
Seasonal adaptations in physiology exhibited by many animals involve an interface between biological timing and specific neuroendocrine systems, but the molecular basis of this interface is unknown. In this study of Siberian hamsters, we show that the availability of thyroid hormone within the hypothalamus is a key determinant of seasonal transitions. The(More)
A cyclic AMP response element (CRE)-luciferase reporter gene assay was used to characterise the functional responses of human melatonin mt(1) and human melatonin MT(2) receptors, stably expressed in the human embryonic kidney cell line HEK293, to a series of six naphthalenic analogues of melatonin. By comparison to the observed melatonin-mediated inhibition(More)
Melatonin receptors bind and become activated by melatonin. The melatonin-related receptor, despite sharing considerable amino acid sequence identity with melatonin receptors, does not bind melatonin and is currently an orphan G protein-coupled receptor. To investigate the structure and function of both receptors, we engineered a series of 14 chimeric(More)
In seasonal mammals, both the growth and reproductive axes are regulated by photoperiod. Female Siberian hamsters were kept, for up to 12 weeks, in long-day (LD) or short-day (SD) photoperiod, from weaning at 3 weeks of age (Exp 1). LD hamsters had characteristically faster growth and higher asymptotic body weight, adiposity, and leptin gene expression in(More)
The Siberian hamster survives winter by decreasing food intake and catabolizing abdominal fat reserves, resulting in a sustained, profound loss of body weight. VGF gene expression is photoperiodically regulated in the hypothalamus with significantly higher expression in lean Siberian hamsters. The aim of this study was to investigate the role of VGF in(More)