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The posterior pituitary (PP) hormones oxytocin (OXT) and arginine vasopressin (AVP) are synthesized within the hypothalamic nucleus and released from the PP into systemic circulation. Hypothalamic AVP projects its axons into the external layer of median eminence (eME) and regulates anterior pituitary hormone secretion during stress responses. Although similar as PP hormones, we demonstrate distinct regulatory roles of estrogen in hypothalamic OXT and AVP dynamics. OXT dynamics in the hypothalamus exhibit sex-dependent variations and that estrogen may influence dynamic OXT level changes, as observed in OXT-mRFP1 transgenic rats. Estrogen was also observed to modulate dynamic changes in AVP levels in the axon terminals of eME in female AVP-eGFP transgenic rats. Although OXT and AVP are produced within the similar hypothalamic region, both exhibit distinct dynamics within the hypothalamus. Estrogen acts on the hypothalamus, and further effects of estrogen replacement therapy can be expected.
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http://dx.doi.org/10.1111/jog.16100 | DOI Listing |
Front Aging Neurosci
August 2025
Diabetes Center and Department of Anatomy, University of California, San Francisco, San Francisco, CA, United States.
Effective communication between the brain and peripheral tissues is crucial for homeostasis and health, and its impairment is a defining feature of aging. Circumventricular organs, characterized by the presence of fenestrated capillaries and absence of a blood-brain barrier (BBB), play a crucial role in controlling substance exchange between the brain and the blood. To date, adaptive changes in fenestrated vasculature in response to environmental insults remain poorly understood.
View Article and Find Full Text PDFCell Metab
September 2025
Wellcome-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB20QQ, UK. Electronic address:
The next generation of obesity medicines harness the activity of the glucose-dependent insulinotropic polypeptide and glucagon-like peptide 1 receptors (GIPR and GLP-1R), but their mechanism of action remains unclear. Here, we report that the GIPR is enriched in oligodendrocytes and GIPR signaling bidirectionally regulates oligodendrogenesis. In mice with adult-onset deletion of GIPR in oligodendrocytes, GIPR agonism fails to enhance the weight-loss effects of GLP-1R agonism.
View Article and Find Full Text PDFCell
September 2025
Division of Neurobiology, Department of Molecular and Cell Biology, Helen Wills Neuroscience Institute, Howard Hughes Medical Institute, University of California, Berkeley, CA 94720, USA. Electronic address:
Sleep is known to promote tissue growth and regulate metabolism, partly by enhancing growth hormone (GH) release, but the underlying circuit mechanism is unknown. We demonstrate how GH release, which is enhanced during both rapid eye movement (REM) and non-REM (NREM) sleep, is regulated by sleep-wake-dependent activity of distinct hypothalamic neurons expressing GH-releasing hormone (GHRH) and somatostatin (SST). SST neurons in the arcuate nucleus suppress GH release by inhibiting nearby GHRH neurons that stimulate GH release, whereas periventricular SST neurons inhibit GH release by projecting to the median eminence.
View Article and Find Full Text PDFPsychoneuroendocrinology
September 2025
Neuroendocrinology Research Laboratory, Department of Studies in Zoology, Karnatak University, Dharwad 580003, India. Electronic address:
Enkephalins are recognised for their role in regulating various physiological functions, including reproduction in vertebrates. Nonetheless, the functional importance of the two forms of enkephalins, methionine-enkephalin (M-ENK) and leucine-enkephalin (L-ENK), remains inadequately understood in the context of the reproductive stress response in reptiles. In the first experiment, we subjected the lizards to various stressors (handling, chasing, noise, and confinement) and assessed the response of enkephalinergic system in the brain and pituitary gland.
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