The vasopressin (VP) and oxytocin (OT) contents of the rat pineal gland during the summer period were determined by RIAs. Both the levels of VP immunoreactivity and OT immunoreactivity rose markedly in August. The highest level of VP immunoreactivity occurred on August 6 [82 +/- 19 fmol/gland (+/- SEM)], compared to basal levels of 14 +/- 2 fmol/gland. Basal levels of OT immunoreactivity of 20 +/- 8 fmol/gland increased to a peak level of 193 +/- 72 fmol/gland on August 14. Analysis of immunoreactive components by HPLC demonstrated that rises were due to the peptides coeluting with authentic VP and OT, respectively. Levels of immunoreactive VP and OT in the hypothalamus, pituitary gland, and hippocampus did not show variation during the summer. The results show that the VP and OT content of the pineal gland is regulated in a tissue-specific fashion by seasonal influences.
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http://dx.doi.org/10.1210/endo-121-5-1716 | DOI Listing |
Gen Comp Endocrinol
July 2005
Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02912, USA.
Juvenile hormone (JH) is a key endocrine regulator of insect metamorphosis, reproduction, and aging. The synthesis of JH is regulated by neuropeptides and biogenic amines, but the molecular and cellular basis of this control remains largely unknown. Genetic analysis of JH synthesis in Drosophila melanogaster mutant for insulin signaling may provide new and powerful insights.
View Article and Find Full Text PDFAm J Physiol Regul Integr Comp Physiol
February 2002
Department of Obstetrics and Gynaecology, Adelaide University, Medical School, Adelaide, South Australia 5005.
There has been relatively little research conducted on pineal melatonin production in laboratory mice, in part, due to the lack of appropriate assays. We studied the pineal and plasma rhythm, response to light, adrenergic stimulation, and metabolism of melatonin in CBA mice. With the use of a sensitive and specific melatonin RIA, melatonin was detected in the pineal glands at all times of the day >21 fmol/gland in CBA mice but not in C57Bl mice.
View Article and Find Full Text PDFJ Neuroendocrinol
July 1998
INSERM U259, Université de Bordeaux II, France.
Neuropeptide FF (NPFF, FLFQPQRFamide) is an FMRFamide-like octapeptide exhibiting antiopiate activity. The presence of both NPFF-immunoreactivity (NPFF-IR) and NPFF-specific receptors has been described in the mammalian central nervous system (CNS). The peripheral effects of NPFF indicate that NPFF-IR material is present outside the CNS.
View Article and Find Full Text PDFJ Endocrinol
November 1994
Department of Medicine, Francis Fraser Laboratory, Royal Postgraduate Medical School, Hammersmith Hospital, London, UK.
We have compared the effects of thyroidectomy with those of thyroxine (T4) replacement and excess T4 treatment on neuropeptide Y (NPY) in the rat anterior pituitary, and compared these with the effects on substance P (SP) and vasoactive intestinal peptide (VIP). Thyroidectomy produced large increases in the peptide content of NPY (335 +/- 58 fmol/gland vs 15 +/- 4 fmol/gland in controls), SP (581 +/- 90 vs 199 +/- 32 fmol/gland) and VIP (1386 +/- 395 vs 417 +/- 77 fmol/gland) together with large increases in the respective prohormone encoding mRNAs, NPY 21,760% +/- 1290%, preprotachykinin-A (PPT-A; which encodes the substance P precursor) 1744% +/- 190% and VIP 680% +/- 129%. Thyroidectomy together with T4 replacement produced an increase in both NPY peptide (426 +/- 72 vs 15 +/- 4 fmol/gland) and mRNA content (970% +/- 156% of controls).
View Article and Find Full Text PDFEndocrinology
April 1992
Department of Medicine, Royal Postgraduate Medical School, Hammersmith Hospital, London, United Kingdom.
Neuromedin-B shows a widespread distribution throughout mammalian neural and peripheral tissues and may be involved in the modulation of a variety of physiological processes. The highest concentrations of neuromedin-B are found in the anterior pituitary gland, suggesting that it may be of physiological importance within this tissue. To examine this hypothesis, we have used Northern blotting to demonstrate that neuromedin-B is present in the anterior pituitary as a result of local synthesis and have examined the effects of endocrine manipulations on its mRNA and immunoreactive peptide content.
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