Daily rhythms are a fundamental feature of all living organisms; most are synchronized by
the 24hr light/dark (LD) cycle. In most species, these rhythms are generated by a circadian …

The pineal organ of teleost fish is a directly photosensory organ that contains photoreceptor
cells similar to those of the retina. It conveys photoperiod information to the brain via neural …

A brief description is given of the discovery of PTHrP and the roles of the peptide in
mammalian physiology. Next, the occurrence of PTHrP in the earliest vertebrates, sharks …

Melatonin and serotonin are indoleamine neurohormones that function as photoperiod
signals in many species and have recently been found in St. John's wort, a medicinal plant …

Photoperiod plays an essential role in the synchronization of metabolism, physiology, and
behavior to the cyclic variations of the environment. In vertebrates, information is relayed by …

In salmonid fishes there are indications that socially subordinate individuals avoid
competition with larger, dominant fish by adjusting daily feeding and activity cycles. As in …

Publisher Summary This chapter focuses on the structural and functional properties of the
fish pineal organ, and on the molecular mechanisms, that contribute to the synthesis of …

Annual variation in photoperiod is the most regular phenomenon that has strong predictive
value in the temporal organization of seasonal activities in biological world, especially …

In all vertebrate species, melatonin is produced during darkness and its formation is
inhibited by light. Melatonin can thus be considered as the hormone of darkness. Because of …

BACKGROUND: The prevalence of insomnia in patients with symptomatic secondary
hyperparathyroidism and the improvements of sleep disturbances after parathyroidectomy …