Disease relevance of Phodopus

• Effects of melatonin agonists and antagonists on reproduction and body weight in the Siberian hamster [1].
• Estrogen accelerates gonadal recrudescence in photo-regressed male siberian hamsters [2].
• Neuropeptide Y induces torpor-like hypothermia in Siberian hamsters [3].
• The present study investigated and compared the effects of central TRH on feeding behavior in Siberian hamsters exposed to long (LP) or short (SP) photoperiods, which induce natural physiological states of obesity and leanness respectively [4].

Psychiatry related information on Phodopus

• Sleep deprivation increases brain serotonin turnover in the Djungarian hamster [5].
• Chronic administration of melatonin reduces REM sleep in the Djungarian hamster (Phodopus sungorus) [6].
• The purpose of the present study was to determine whether carbachol, a cholinergic agonist, mimics the phase-shifting effects of light on the circadian rhythm of locomotor activity (CRLA) in the Djungarian hamster [7].
• Circulating ghrelin levels and central ghrelin receptor expression are elevated in response to food deprivation in a seasonal mammal (Phodopus sungorus) [8].

High impact information on Phodopus

• Preadipocytes isolated from brown adipose tissue (BAT) of the djungarian dwarf hamster Phodopus sungorus are able to proliferate and differentiate in vitro into true brown adipocytes able to express the BAT marker protein the uncoupling protein (UCP) [9].
• Refractoriness to melatonin occurs independently at multiple brain sites in Siberian hamsters [10].
• The distribution of vasopressin receptors was studied in the brain of a photoperiodic animal, the Siberian hamster [11].
• Unexpectedly, the Mel1b receptor gene of the Siberian hamster, Phodopus sungorus, cannot encode a functional receptor; two nonsense mutations are present within the coding region [12].
• We have previously shown that the administration of exogenous 17beta-estradiol (E(2)) to adult male Siberian hamsters kept under long-day photoperiod increased testicular mass without altering spermatogenesis [2].

Biological context of Phodopus

• Melatonin receptors and signal transduction in photorefractory Siberian hamsters (Phodopus sungorus) [13].
• Serum levels of 17 beta-estradiol and progesterone were assayed at 4- to 5-h intervals across the estrous cycle in female Djungarian hamsters, Phodopus campbelli [14].
• Evidence for a direct effect of melatonin on mitochondrial genome expression of Siberian hamster brown adipocytes [15].
• Cyclic Djungarian hamsters, Phodopus campbelli, lack the progesterone surge normally associated with ovulation and behavioral receptivity [14].
• High affinity binding sites for luteinizing hormone-releasing hormone (LHRH) were characterized in Djungarian hamsters [16].

Anatomical context of Phodopus

• Using the photoperiodic Djungarian hamster, we assessed the role of the maternal pineal gland and its hormone, melatonin, in this prenatal perception of daylength [17].
• Melatonin signal transduction was examined in median eminence/pars tuberalis (ME/PT) explants from Djungarian hamsters [18].
• Pelage color cycles and hair follicle tyrosinase activity in the Siberian hamster [19].
• Phosphorylation of CREB was stimulated by D1-R agonists in both Syrian and Siberian hamster hypothalamus, but the response was far greater in Syrian hamster tissue (+138%+/-28%) than in Siberian hamster tissue (+43%+/-11%) [20].
• In the incubations of testes from both LD and SD Siberian hamsters, norepinephrine was most effective in stimulating testosterone production, followed by epinephrine and phenylephrine, while isoproterenol failed to increase testosterone accumulation [21].

Associations of Phodopus with chemical compounds

• Development of Phodopus sungorus brown preadipocytes in primary cell culture: effect of an atypical beta-adrenergic agonist, insulin, and triiodothyronine on differentiation, mitochondrial development, and expression of the uncoupling protein UCP [9].
• Testosterone and estrogen act via different pathways to inhibit puberty in the male Siberian hamster (Phodopus sungorus) [22].
• Mature male and ovariectomized estrogen-treated female Siberian hamsters were kept in long (LD; 16 h of light, 8 h of darkness) or short days (SD; 8 h of light, 16 h of darkness) for 8 weeks, and recombinant murine leptin (15 microg/day) was infused for 2 weeks via osmotic minipumps [23].
• Hourly injection of norepinephrine during a continuation of light into the normal dark period stimulated increases in the activity of serotonin N-acetyltransferase and melatonin content in the Djungarian hamster but was without effect on these pineal parameters in the Syrian hamster [24].
• Serotonin content and melatonin production in the pineal gland of the male Djungarian hamster (Phodopus sungorus) [25].

Gene context of Phodopus

• The results showed that specific TRH-R mRNA, 3.8 kb in size, was identified in Siberian hamster testes and the mRNA levels were significantly elevated in the EDS-treated testes compared to the controls (p < 0.01) [26].
• This study investigated whether the gene for peripherin, a protein previously considered to play only a role in the retina, may also be expressed in the pineal gland of both Djungarian hamsters (Phodopus sungorus) and humans [27].
• Are the short-photoperiod-induced decreases in serum prolactin responsible for the seasonal changes in energy balance in Syrian and Siberian hamsters [28]?
• Photoperiodic regulation of androgen receptor and steroid receptor coactivator-1 in Siberian hamster brain [29].
• Our studies of the Siberian hamster SCN have shown that two types of neuropeptide-containing neurons, vasopressin (AVP) and vasoactive intestinal peptide (VIP) neurons, respond to short photoperiod by decreasing mRNA expression [30].

Analytical, diagnostic and therapeutic context of Phodopus

• The aim of this study was to investigate a genetic effect of melatonin on isolated Siberian hamster brown adipocytes using differential display RT-PCR (DDRT-PCR) [15].
• To monitor pineal function in the Djungarian hamster (Phodopus sungorus), we measured the urinary excretion of the melatonin metabolite 6-sulphatoxymelatonin (aMT6s) at 3-hr intervals by radioimmunoassay [31].
• By light- and electron-microscopic immunohistochemistry, we demonstrated that the tanycytes of Djungarian hamsters were intensely immunostained with the vimentin monoclonal antibody V9 [32].
• Diurnal variation in 5-hydroxyindole-acetic acid output in the suprachiasmatic region of the Siberian hamster assessed by in vivo microdialysis: evidence for nocturnal activation of serotonin release [33].
• As late-term pregnancies failed to survive bilateral ovariectomy and the placenta contained little extractable progesterone, it appears that the progesterone of Djungarian hamster pregnancy is synthesized by the corpus luteum throughout gestation [34].

References