..., instructions or products referred to in the content or advertisements. Melatonin Photoperiod Season Reproduction Hamster Kiss1 gene Dio2 gene RFamide-related peptides RFamide peptides Reproduction is a highly complex function orchestrated by the hypothalamic-pituitary-gonadal (HPG...

...Peter Redecker; Yalcin Cetin; Dietrich Grube In the anterior pituitary of rat, gerbil, hamster and guinea pig, the presence and cellular distribution of the synaptic vesicle-associated proteins synaptotagmin I and rab3 were analyzed by immunoblotting and by immunocytochemical staining of serial...

... in the Golden Syrian hamster to address the following questions: (a) Do allografts of adult adenohypophysial tissue which elevate serum PRL levels decrease the concentration of PRL mRNA in the host’s adenohypophysis? (b) Is this effect shared by allografts of neonatal hypophysial tissue or neonatal muscle...

...) of the adult Siberian hamster. In the adult brain PSA-NCAM is located in regions capable of undergoing morphological rearrangements and thus is generally considered to be an indicator of neural plasticity. Immunostaining for PSA in the Siberian hamster SCN (using a monoclonal antibody against the α2,8-linked...

...Mary K. Vaughan; Armando Menendez-Pelaez; Gerald R. Buzzell; George M. Vaughan; John C. Little; Russel J. Reiter Two groups of young adult male Syrian hamsters were kept in a vivarium at 22°C and a light :dark cycle of 14.5:9.5 h (lights on 06.30 h; indoor) or in a naturally decreasing photoperiod...

... direct and indirect effects of melatonin on pituitary gonadotropin basal secretion and responsiveness to GnRH stimulation. Anterior pituitaries from adult male golden hamsters were perifused with an APS 10 perifusion system for 6 h. Both basal secretion and secretion in response to hourly GnRH...

...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...

... in the male Syrian hamster. Our study examined whether daylength influences formation of estrogen in the preoptic area (POA) and other neuroendocrine areas (anterior hypothalamus, AHT, and medial amygdala, MA) which are targets for T in behaviorally active males. Estrogen formation in individual brain samples...

...Nancy A. Alexiuk; Jerry Vriend The effects of daily afternoon melatonin injections on the accumulation of monoamines were studied in extracts of median eminence, and of caudate nucleus, of intact and ovariectomized Syrian hamsters which were administered pargyline 2 h prior to sacrifice. Although...

...John S. Massa; David E. Blask Light deprivation by blinding or exposure to short photoperiod results in depressed prolactin (PRL) cell activity and gonadal regression in the male Syrian hamster after at least 42–56 days of treatment, and both of these events can be prevented if pineal removal...

...K. Michael Orstead; David E. Blask The purpose of this investigation was to elucidate the differences in the nature and time course of changes in in vitro prolactin (PRL) cell activity between blinded and blind/pinealectomized female hamsters. Adult female golden hamsters were either left intact...

... the presence and the topography of two corticosteroid receptor systems (type I and type II) in hamster and rat brains. In the rat, the in vivo autoradiograms clearly revealed the retention by the type I receptor of tracer amount of [ 3 H]corticosterone, primarily in the CA1 and CA2 cell field, dentate gyrus...

...Richard W. Steger; Kathleen S. Matt; Andrzej Bartke Exposure of adult male golden hamsters to short days (< 12.5 h light/day) leads to suppression of gonadal function which is secondary to reductions in gonadotropin and prolactin (PRL) secretion. Short-day (SD) exposure also leads to a reduction...

...George M. Vaughan; Arthur D. Mason, Jr.; Russel J. Reiter A single injection of 25 µg melatonin was given subcutaneously in 0.1 ml saline either at 3 h into the light phase (morning) in female Syrian hamsters or at 1 h before the beginning of the dark phase (evening) in males (L/D 14/10 h). In both...

...Jean Hine; Margaret Ward Orsini; Linda R. Hegstrand Brain histamine levels were determined in golden hamster hypothalamus and ‘brain minus hypothalamus’ on each of the 4 days of the estrous cycle and on selected days of pregnancy. The highest histamine content of the hypothalamus was observed...

...Albert A. Lamperti An in vitro bioassay was used to characterize the pattern of follicle-stimulating hormone (FSH)- and luteinizing hormone (LH)-releasing activities in the anterior (AH) and medial basal hypothalamus (MBH) during proestrus (P) and estrus (E) in the hamster. Regularly cycling...

...Mary K. Vaughan; Bruce A. Richardson; Larry J. Petterborg; Anke P. Holtorf; George M. Vaughan; Thomas H. Champney; Russel J. Reiter Plasma thyroid hormone concentrations in male and female Syrian hamsters were evaluated in five experiments after two pineal indoles, melatonin (MEL) and 5...

...Gail A. Eskes; Michael Wilkinson; Raj Bhanot Short-day-induced testicular regression in golden hamsters is accompanied by changes in opiatergic control of LH release. Serum LH in long-day-exposed hamsters is elevated by subcutaneous injections of naloxone. By day 42 of short-day exposure, naloxone...

...Kay L. Jorgenson; Neena B. Schwartz The purpose of these experiments was to determine whether daily gonadotropin surges that occur in intact or ovariectomized hamsters kept in short days (less than 12 h of light/day) are manifest because of extremely low levels of steroids. Hamsters were...

... determined in both female and male Syrian hamsters that were either blind, blind and pinealectomized or left intact for 14 weeks. PRL release was determined in vivo by measuring the amount of immunoreactive (RIA) PRL in the serum of the animals in each group with a heterologous RIA for hamster PRL. Blinding...