Intrahypothalamic Neurohormonal Interactions in the Control of Growth Hormone Secretion

Epelbaum, Jacques

doi:10.1002/9780470514283.ch5

Cited by 9 publications

(3 citation statements)

References 34 publications

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“…GH release is stimulated by growth hormone‐releasing hormone (GHRH) synthesised in neurones located in the ventrolateral portion of the ARC (49,50). SRIF receptors are present on GHRH neurones, facilitating cross‐talk between SRIF and GHRH to regulate GH secretion from the pituitary (51–53). However, the role of SRIF expressed in ARC neurones is less well established.…”

Section: Discussionmentioning

confidence: 99%

Hypothalamic Gene Expression Rapidly Changes in Response to Photoperiod in Juvenile Siberian Hamsters (Phodopus sungorus)

Herwig

Petri

Barrett

2012

J Neuroendocrinology

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Siberian hamsters are seasonal mammals that survive a winter climate by making adaptations in physiology and behaviour. This includes gonadal atrophy, reduced food intake and body weight. The underlying central mechanisms responsible for the physiological adaptations are not fully established but involve reducing hypothalamic tri-iodthyronine (T3) levels. Juvenile Siberian hamsters born or raised in short days (SD) respond in a similar manner, although with an inhibition of gonadal development and growth instead of reversing an established long day (LD) phenotype. Using juvenile male hamsters, the present study aimed to investigate whether the central mechanisms are similar before the establishment of the mature LD phenotype. By in situ hybridisation, we examined the response of genes involved in thyroid hormone (Dio2 and Dio3, which determine hypothalamic T3 levels) and glucose/glutamate metabolism in the ependymal layer, histamine H3 receptor and VGF as representatives of the highly responsive dorsomedial posterior arcuate nucleus (dmpARC), and somatostatin, a hypothalamic neuropeptide involved in regulating the growth axis. Differential gene expression of type 2 and type 3 deiodinase in the ependymal layer, histamine H3 receptor in the dmpARC and somatostatin in the ARC was established by the eighth day in SD. These changes are followed by alterations in glucose metabolism related genes in the ependymal layer by day 16 and increased secretogranin expression in the dmpARC by day 32. In conclusion, our data demonstrate similar but rapid and highly responsive changes in gene expression in the brain of juvenile Siberian hamsters in response to a switch from LD to SD. The data also provide a temporal definition of gene expression changes relative to physiological adaptations of body weight and testicular development and highlight the likely importance of thyroid hormone availability as an early event in the adaptation of physiology to a winter climate in juvenile Siberian hamsters.

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Section: Discussionmentioning

confidence: 99%

Hypothalamic Gene Expression Rapidly Changes in Response to Photoperiod in Juvenile Siberian Hamsters (Phodopus sungorus)

Herwig

Petri

Barrett

2012

J Neuroendocrinology

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“…However, this has not always been the case. Because of its proximity to the ME and the hypophysial portal vasculature, the major focus of earlier studies of the ARH was as a mediator of reproductive function and anterior pituitary secretion, particularly prolactin and growth hormone secretion (e.g., (770)(771)(772)). Indeed, the fact that ARH kisspeptin neurons are part of the GnRH pulse generator ( 642) usefully reminds us that this nucleus is involved with functions other energy balance.…”

Section: Arcuate Nucleusmentioning

confidence: 99%

The physiological control of eating: signals, neurons, and networks

Watts

Kanoski

Sanchez‐Watts

et al. 2022

Physiological Reviews

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During the past 30 years, investigating the physiology of eating behaviors has generated a truly vast literature. This is fueled in part by a dramatic increase in obesity and its comorbidities that has coincided with an ever increasing sophistication of genetically based manipulations. These techniques have produced results with a remarkable level of cell-specificity-particularly at the cell signaling level-and have played a lead role in advancing the field. However, putting these findings into a brain-wide context that connects physiological signals and neurons to behavior and somatic physiology requires a thorough consideration of neuronal connections; a field that has also seen an extraordinary technological revolution. Our goal is to present a comprehensive and balanced assessment of how physiological signals associated with energy homeostasis interact at many brain levels to control eating behaviors. A major theme is that these signals engage sets of interacting neural networks throughout the brain, that are defined by specific neural connections. We begin by discussing some fundamental concepts-including ones that still engender vigorous debate-that provide the necessary frameworks for understanding how the brain controls meal initiation and termination. These include: key word definitions, ATP availability as the pivotal regulated variable in energy homeostasis, neuropeptide signaling, homeostatic and hedonic eating, and meal structure. Within this context, we discuss network models of how key regions in the endbrain (or telencephalon), hypothalamus, hindbrain, medulla, vagus nerve, and spinal cord work together with the gastrointestinal tract to enable the complex motor events that permit animals to eat in diverse situations.

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“…During the development of the hypothalamus, SOM produced by neuroendocrine neurons of the ventromedial nucleus (VMN) exerts several actions influencing synaptogenesis and neural proliferation (Goodyer, Grigorakis, Patel, & Kumar, 2004) and regulating the sexually dimorphic patterns of GH secretion (Gillies, 1997). These neurons control the rate of secretion of GH, responding to high circulating concentrations of GH by increasing the release of SOM (Epelbaum, 1992).…”

Section: Introductionmentioning

confidence: 99%

Neurochemical characterization of the hypothalamus of the early fetal and newborn alpaca Vicugna pacos

Montelli

Graïc

Ruiz

et al. 2019

The Anatomical Record

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In this study we performed a neurochemical characterization of the hypothalamus in the developing alpaca (Vicugna pacos) with the aim of revealing the distributions of immunoreactive (-ir) cells containing parvalbumin (PV), calbindin (CB), calretinin (CR), the somatostatin (SOM), the enzyme aromatase P450 (P450Arom), the estrogen receptor α (ER-α), and estrogen receptor β (ER-β) in embryonal stages, early fetal age, and in the newborn. This analysis has been carried out on embryos at 20, 30, 45 days, fetuses at 90 days, and newborn alpaca. Our immunohistochemical results revealed no cells-ir throughout the embryonic hypothalami of 20, 30, and 45 days. On the fetal stage of 90 days, SOM-ir cells were observed in the lateral hypothalamus and the ventromedial nuclei of the tuberal region. We checked for the presence of P450Arom-ir cells in the periventricular area and dorsomedial hypothalamic nucleus of the tuberal region. In these fetal stages, no PV-ir, CB-ir, CR-ir or ERs-ir cells were identified. In the newborn, the PV-ir, CB-ir, CR-ir, and SOMir cells were detected in both the anterior and tuberal hypothalamic area. The P450Arom-ir cells the ER-α-ir and ER-β-ir cells were found in the anterior hypothalamus. Our results offer a contribution in the future purpose to obtain a time-expression pattern of the considered markers in alpaca during gestation and represents a foundation for future investigations on the alpaca brain to define the cross talk between PV, CB, CR, P450Arom, SOM, and ERs in the hypothalamus, the strategic region for the control of the reproductive behavior.

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Intrahypothalamic Neurohormonal Interactions in the Control of Growth Hormone Secretion

Cited by 9 publications

References 34 publications

Hypothalamic Gene Expression Rapidly Changes in Response to Photoperiod in Juvenile Siberian Hamsters (Phodopus sungorus)

Hypothalamic Gene Expression Rapidly Changes in Response to Photoperiod in Juvenile Siberian Hamsters (Phodopus sungorus)

The physiological control of eating: signals, neurons, and networks

Neurochemical characterization of the hypothalamus of the early fetal and newborn alpaca Vicugna pacos

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