Prolonged fasting is associated with a number of changes in the thyroid axis manifested by low serum T3 and T4 levels and, paradoxically, or normal TSH. This response is, at least partly, caused suppression proTRH gene expression neurons hypothalamic paraventricular nucleus (PVN) reduced TRH release. Because fall hormone can be blunted mice systemic administration leptin, we raised possibility that leptin may have an important role neuroendocrine regulation axis, through effects on...

The hypothalamic arcuate nucleus has an essential role in mediating the homeostatic responses of thyroid axis to fasting by altering sensitivity prothyrotropin-releasing hormone (pro-TRH) gene expression paraventricular (PVN) feedback regulation hormone. Because agouti-related protein (AGRP), a leptin-regulated, nucleus-derived peptide with α-MSH antagonist activity, is contained axon terminals that terminate on TRH neurons PVN, we raised possibility may also participate mechanism which...

To identify the specific locations of type 2 deiodinase (D2) messenger RNA (mRNA) in hypothalamus and pituitary gland determine its regulation by thyroid hormone, we performed situ hybridization histochemistry, Northern analysis, quantitative RT-PCR euthyroid, hypothyroid, hyperthyroid rats. By silver grains were concentrated over ependymal cells lining floor infralateral walls third ventricle extending from rostral tip median eminence (ME) to infundibular recess, surrounding blood vessels...

High concentrations of pituitary adenylate cyclase-activating polypeptide (PACAP) nerve fibers are present in the central nucleus amygdala (CeA), a brain region implicated control fear-related behavior. This study evaluated PACAPergic modulation fear responses at CeA male Sprague-Dawley rats. PACAP (50–100 pmol) microinfusion via intra-CeA cannulae produced increases immobility and time rats spent withdrawn into corner opposite to electrified probe compared controls shock-probe...

Type 3 iodothyronine deiodinase (D3) is a selenoenzyme that inactivates thyroid hormone. It necessary for T3 homeostasis in the central nervous system. D3 activity has been identified many regions of brain and parallels status, but level at which it regulated its specific cellular locations are not known. We evaluated effect status on expression gene within system using situ hybridization histochemistry. messenger RNA (mRNA) was throughout, with high focal hippocampal pyramidal neurons,...

Recent evidence suggests that neuropeptide Y (NPY), originating in neurons the hypothalamic arcuate nucleus, is an important mediator of effects leptin on central nervous system. As these NPY innervate hypophysiotropic paraventricular nucleus (PVN) produce tripeptide, TRH, we raised possibility may be responsible for resetting hypothalamic-pituitary-thyroid (HPT) axis during fasting. To test this hypothesis, intracerebroventricularly administered circulating thyroid hormone levels and proTRH...

Neuropeptide Y (NPY) immunoreactive (-ir) nerve fibers densely innervate hypophysiotropic TRH perikarya and dendrites in the hypothalamic paraventricular nucleus (PVN). To evaluate contribution of arcuate (Arc) to this innervation, effect Arc ablation by neonatal monosodium glutamate (MSG) treatment on density NPY-fibers contacting neurons PVN was investigated. After lesioned animals vehicle-treated controls reached adulthood, number contacts between NPY-ir boutons TRH-ir determined...

Fasting results in reduced thyroid hormone levels and inappropriately low or normal thyroid-stimulating (TSH), partly attributed to central hypothyroidism due suppression of pro TRH gene expression the hypothalamic paraventricular nucleus. Recently, we demonstrated that systemic administration leptin fasting animals restores plasma thyroxine (T4) proTRH mRNA nucleus normal, suggesting fall circulating during acts as a signal hypophysiotropic neurons reset set point for feedback regulation by...

Prolonged fasting is associated with a number of changes in the thyroid axis manifested by low serum T3 and T4 levels and, paradoxically, or normal TSH. This response is, at least partly, caused suppression proTRH gene expression neurons hypothalamic paraventricular nucleus (PVN) reduced TRH release. Because fall hormone can be blunted mice systemic administration leptin, we raised possibility that leptin may have an important role neuroendocrine regulation axis, through effects on...

Gene expression for agouti-related protein (AGRP), an endogenous antagonist of melanocortin receptors, has been localized to the hypothalamic arcuate nucleus, where it colocalizes with neuropeptide Y (NPY). Having reported that NPY innervation hypophysiotropic TRH neurons in paraventricular nucleus (PVN) originates primarily from NPY-producing here we examined possibility PVN are similarly innervated by AGRP nerve terminals. Using immunohistochemistry, AGRP-containing cell bodies were found...

Pituitary adenylate cyclase-activating-polypeptide (PACAP) is a new member of the secretin/glucagon/vasoactive intestinal peptide family peptides; it occurs as two amidated forms with 38 (PACAP38) and 27 (PACAP27) amino acids. Rabbit antisera against synthetic PACAP27 were characterized by enzyme-linked immunosorbent assay. One antisera, using high antibody titer, recognized both PACAP38 was found useful for immunohistochemistry. The distribution ultrastructural localization PACAP-like...

Abstract The hypothalamic paraventricular nucleus (PVN) coordinates major neuroendocrine and behavioral mechanisms, particularly responses to homeostatic challenges. Parvocellular magnocellular PVN neurons are richly innervated by pituitary adenylate cyclase‐activating polypeptide (PACAP) axons. Our recent functional observations have also suggested that PACAP may be an excitatory neuropeptide at the level of PVN. Nevertheless, exact localization PACAP‐producing project is not understood....

The goal of the present investigation was to analyze types 2 (D2) and 3 (D3) iodothyronine deiodinases in various structures within central nervous system (CNS) response iodine deficiency. After 5–6 wk low-iodine diet (LID) or LID + μg potassium iodide/ml (LID+KI; control), rats' brains were processed for situ hybridization histochemistry D2 D3 mRNA dissected, frozen liquid nitrogen, activities. did not affect weight gain serum triiodothyronine, but plasma thyroxine (T 4 ) undetectable. In...

The corticotropin-releasing hormone (CRH) gene contains a perfect palindromic motif in its promoter region that allows binding of the cyclic adenosine monophosphate response element protein, CREB. Since previous studies suggest CRH can be activated by mono-phosphate, we determined whether stress and feedback inhibition glucocorticoids CRH-producing neurons hypothalamic paraventricular nucleus could mediated changes phosphorylation Antisera to CREB phospho-CREB Ser133 (PCREB), active...