...Preeti Gupta; Sayantan Sur; Asma Naseem; Shalie Malik Introduction: Light is the primary source of energy and regulates seasonal changes in physiology and behavior. The role of photoperiod has been much investigated in several bird species, but the role of illumination in seasonal adaptations...

...Sunantha Kosonsiriluk; Voravasa Chaiworakul; Aree Thayananuphat; Laura J. Mauro; Mohamed E. El Halawani Background/Aims: Photoperiod is a major environmental cue in temperate-zone birds which synchronizes breeding with the time of year that offers the optimal environment for offspring survival...

..., instructions or products referred to in the content or advertisements. Lipolysis Testicular regression Photoperiod Lesion National Institutes of Health (NIH) 10.13039/100000002 Obesity is the fastest growing health threat in the United States and many countries worldwide [ 1 ] due...

...Florent G. Revel; Mireille Masson-Pévet; Paul Pévet; Jens D. Mikkelsen; Valérie Simonneaux In seasonal species, the photoperiod (i.e. day length) tightly regulates reproduction to ensure that birth occurs at the most favourable time of year. In mammals, a distinct photoneuroendocrine circuit...

...Stefan Reuss; James Olcese The distribution of neuropeptide Y-like immunoreactivity (NPY-LI) was investigated by immunohistochemistry and radioimmunoassay (RIA) in the brain of the Djungarian hamster ( Phodopus sungorus ) held under either long or short photoperiods. In the diencephalic...

...-day photoperiod. Potential concurrent changes in the sensitivity of pituitary lactotropes to the inhibitory actions of dopamine on PRL release were investigated in tissue harvested from animals that had been preexposed to either a stimulatory, long-day 16-hour-light:8-hour-dark (16L:8D) photoperiod...

... constant darkness. Under L/D, photoperiod is the dominant entraining stimulus for the melatonin secretion rhythm. It was high during the dark phase and low during the light phase, either under cold light/warm dark or under warm light/cold dark conditions. Under a warm light/cold dark cycle, the amplitude...

...Alexander Lerchl; Stefan Schlatt In order to investigate female Djungarian hamsters’ reactions to changes of the photoperiod, the following two experiments were performed. Experiment I: Age-matched female hamsters were exposed to either short (8L:16D) or long days (16L:8D) for 38 weeks. Initially...

... of the melatonin binding sites by melatonin itself. 12 12 1991 12 06 1992 8 4 2008 Melatonin receptors Daily rhythm Suprachiasmatic nuclei Pars tuberalis Photoperiod © 1992 S. Karger AG, Basel 1993 Copyright / Drug Dosage / Disclaimer Copyright: All rights reserved. No part...

...Heiko T. Jansen; Gary L. Jackson The purpose of this study was to determine if bilateral olfactory bulb removal (Bulbx) alters photoperiod-induced changes of gonadotropin and prolactin secretion in the ewe. Ovariectomized (group 1; n = 12) or ovariectomized estradiol-treated (group 2; n = 12...

... female hamsters received sham surgery or horizontal knife cuts placed ventral to the PVN so as to sever dorsally projecting fibers from the SCN and were either immediately transferred to a short-day photoperiod [10 h light: 14 h dark (10L: 14D); experiment (exp.) 1A] or returned to the long-day...

... responses. Photoperiod Cholera toxin-conjugated horseradish peroxidase Circadian rhythms Obesity Original Paper Neuroendocrinology 1992;55:552-562 Marvindra P. Maharaj Timothy G. Youngstrom Timothy J. Bartness Departments of Psychology and of Biology, Behavior and Neurobiology Program, Georgia...

... to either a long (16 h light/8 h dark) or a short (8 h light/16 h dark) photoperiod. Similar to pinealectomy, knife cuts placed ventral to the PVN, so as to disrupt transfer of photic information to the pineal gland, resulted in a rapid decline in circulating prolactin (PRL) and follicle-stimulating hormone...

... area and, possibly, the diagonal band of Broca as involved in the photoperiodic control of reproductive development. Moreover, the association of fewer morphologically unipolar GnRH neurons in these areas with delayed puberty, as induced by short day or melatonin treatment, suggests the involvement...

... activity is inhibited by day lengths exceeding 10 h. In animals maintained under a natural photoperiod, SCN destruction performed during the period of maximum sexual activity (February) was shown to have no effect on onset of the testicular inactive period which begins at the end of winter and continues...

... photoperiods. In situ histochemistry was performed using a 32 P-labelled 66-nucleotide long oligomer complementary to the sequence of the human GnRH mRNA coding region. The oligonucleotide hybridized specifically to mRNA encoding the GnRH precursor as suggested by the distribution of labelled neurons...

.... Intact or castrated male hamsters with subcutaneously inserted testosterone implants were exposed to long-day (14:10) or short-day photopenods (10:14) for 4-8 weeks. Exposure to short photoperiod for 4 weeks, an interval characterized by a suppression of gonadotropin secretion but not gonadal regression...

... on behavioral criteria as being sexually active, were maintained on long (16:8LD) or short (8:16LD) daylength for 16 weeks. Two further groups of males either intact or castrated and T-treated were shifted after 7 weeks from the long photoperiod to 12:12LD. POA, AHT and MA areas of sexually active males...

...Gail S. Prins; Andrzej Bartke; Richard W. Steger Testosterone (T) feedback sensitivity is markedly altered in adult male golden hamsters following exposure to short photoperiods (SD). Using a technique which measures total androgen receptors within the cell nucleus, the present study examined...

...Lewis C. Krey; Elettra Ronchi; Eric L. Bittman In an effort to understand the potential neuroendocrine mechanisms underlying photoperiodic control of fertility in seasonally breeding species, we monitored the intracellular processing and nuclear uptake of [1α,2α- 3 H]testosterone ( 3 H-T) within...