Centrally Administered Murine Leptin Stimulates Plasma Arginine-Vasopressin Secretion and Increases the Level of mRNA Expression in the Supraoptic Nucleus of Conscious Rats

Yamamoto, Shigeki; Morimoto, Isao; Kai, Keiko; Arao, Tadashi; Fujihira, Takashi; Morita, Emiko; Kannan, Hiroshi; Eto, Sumiya

doi:10.1159/000054478

Cited by 33 publications

(20 citation statements)

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“…We recently reported that administration of leptin (10–400 pmol/rat i.c.v.) induces increases in plasma AVP levels and AVP gene expression in the PVN and SON in the same experimental model as done in this experiment [17]. AVP is a potent secretagogue for ACTH secretion and plays a role as a coregulator, with CRH, on pituitary corticotroph cells [18, 19].…”

Section: Discussionmentioning

confidence: 92%

“…Colocalization of CRH and AVP is observed in parvocellular neurons of the PVN, and both peptides are secreted into the hypophysial-portal circulation by certain stimuli [16]. We recently reported that intracerebroventricular administration of leptin causes increases in plasma AVP levels and AVP mRNA expression in the PVN and supraoptic nucleus (SON) of conscious rats [17]. AVP secretion into the portal blood potentiates the effect of CRH on ACTH secretion from the anterior pituitary [18, 19].…”

Section: Introductionmentioning

confidence: 99%

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Centrally Administered Murine-Leptin Stimulates the Hypothalamus-Pituitary- Adrenal Axis through Arginine-Vasopressin

Morimoto¹,

Yamamoto²,

Kai³

et al. 2000

Neuroendocrinology

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Starvation induces a decrease in circulating leptin levels and activation of the hypothalamus-pituitary-adrenal (HPA) axis. Leptin inhibits the HPA axis in unfed rodents or genetically leptin-deficient ob/ob mice, whereas it stimulates corticotropin-releasing hormone (CRH) gene expression in the paraventricular nucleus (PVN). However, the interactions between leptin, CRH and the HPA axis are poorly understood and are likely to be complex. We recently demonstrated that central leptin administration caused increases in plasma arginine-vasopressin (AVP) and AVP gene expression of the PVN in nonstressful rats. AVP stimulates the release of adrenocorticotropic hormone (ACTH), but it also potentiates the action of CRH on ACTH release. In this study, we investigated the effects of leptin on plasma ACTH and corticosterone levels, CRH mRNA of the PVN and proopiomelanocortin (POMC) mRNA of the pituitary in nonstrained rats. Intracerebroventricularly administered leptin caused increases in plasma ACTH and corticosterone levels in dose-dependent manners. In Northern blot analyses, the leptin injection induced significant increases in the expression of CRH mRNA in the PVN and POMC mRNA in the pituitary. The increased plasma ACTH and corticosterone levels by leptin were attenuated with intracerebroventricular pretreatment of a V_1a receptor antagonist (OPC-21268) or a V_1a/V_1b receptor antagonist (dP[Tyr(Me)²]AVP), but not with that of a V₂ receptor antagonist (OPC-31260). The leptin-induced CRH mRNA expression in the PVN and POMC mRNA expression in the pituitary were also reduced by the pretreatment with OPC-21268 and dP[Tyr(Me)²]AVP. These results suggest that intracerebroventricular leptin administration activates the HPA axis by AVP receptor activation through V_1a receptors in the PVN which in turn activates CRH neurons to drive ACTH and corticosterone secretion in concert with AVP in nonstrained rats.

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Section: Discussionmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Centrally Administered Murine-Leptin Stimulates the Hypothalamus-Pituitary- Adrenal Axis through Arginine-Vasopressin

Morimoto¹,

Yamamoto²,

Kai³

et al. 2000

Neuroendocrinology

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“…Our results add new evidence in favour of an inhibitory effect of leptin on HPA axis function in a different stress paradigm, the insulin-stimulated HPA axis activity. The mechanism by which leptin inhibited HPA axis response in this design could be due to direct effects at the hypothalamic [7, 8, 9]and adrenal [13]levels rather than upon the pituitary gland [28]; however, the main site of action of leptin appears to be the hypothalamus. In fact, such an inhibitory effect of leptin on low glucose-stimulated CRH output by perifused hypothalami has been reported [28].…”

Section: Discussionmentioning

confidence: 99%

“…The long variant of leptin receptor (Ob-Rb) has been found in the hypothalamus [5, 6]; leptin increases hypothalamic CRH- [7]and vasopressin (AVP)-ergic [8]functions, although an inhibitory effect of leptin on the CRH-ergic function in ob/ob mice has also been described [9]. Ob-Rbs have been found in normal and tumoral anterior pituitary cells of different mammals [10, 11]; activation of these receptors is likely to stimulate ACTH secretion [12].…”

Section: Introductionmentioning

confidence: 99%

Food Intake-Induced Leptin Secretion Modulates Hypothalamo-Pituitary-Adrenal Axis Response and Hypothalamic Ob-Rb Expression to Insulin Administration

et al. 2000

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The mutation of the ob gene is known to induce a phenotype of obesity accompanied by symptoms including enhanced production of glucocorticoid. Chronic administration to ob/ob mice of leptin, the ob gene product, reverses hypercorticosteronemia. This establishes a clear relation between adipocyte and hypothalamo-pituitary-adrenal (HPA) axis functions. In the present study we investigated the acute modulatory effects of food intake-stimulated leptin secretion on HPA axis activity and hypothalamic leptin receptor (Ob-Rb) expression in 24-hour fasting, adult female, BALB/c mice after insulin-induced hypoglycemia. Our results indicate that: (1) food supply for 45 min to 24-hour fasting mice increased plasma glucose levels and reversed both hypercorticosteronemia and hypoleptinemia; (2) the insulin-induced hypoglycemia produced a marked HPA axis activation in animals with no access to food but this response was fully prevented by food intake and the consecutive increase in plasma leptin levels; (3) the inhibitory effect of leptin on the HPA axis response to insulin-induced hypoglycemia was corroborated by i.p. administration of murine leptin, and (4) fasting-induced hypothalamic Ob-Rb overexpression is not modulated by insulin itself but by leptin, since increase in leptin levels by food intake or by administration of exogenous leptin completely reversed this Ob-Rb overexpression. These results confirm the inhibitory effect of leptin on the HPA axis response to various stress stimuli. They clearly demonstrate that acute food intake in 24-hour fasting mice: (a) rapidly reduced fasting-induced hypercorticosteronemia by enhancing both spontaneous and insulin-elicited endogenous leptin secretion; (b) fully prevented HPA axis response to insulin administration, by rapidly increasing endogenous leptin secretion and probably also by diminishing the extent and the duration of insulin-induced hypoglycemia, and (c) abolished hypothalamic Ob-Rb overexpression induced by fasting itself combined with insulin treatment. The present data strongly suggests an inhibitory effect of endogenous leptin on insulin-induced HPA axis response, an interaction relevant to the physiological adaptation to starvation and caloric excess, and further supports the pivotal role played by the hypothalamus in restoring homeostasis in different allostatic states.

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“…Photoperiod alone did not influence Avpr1a mRNA expression either in the brain or in the testes. In rats intracerebroventricular administration of leptin significantly increased vasopressin mRNA expression in the supraoptic nucleus of the hypothalamus (Yamamoto et al, 1999). In another study central administration of leptin to rats, has been shown to activate Avpr1a in the paraventricular nucleus of the hypothalamus to regulate neuroendocrine axes such as the hypothalamus-pituitary-adrenal axis (Morimoto et al, 2000).…”

Section: Discussionmentioning

confidence: 92%

Long-day photoperiod interacts with vasopressin and food restriction to modulate reproductive status, and vasopressin receptor expression of male Golden spiny mice

Ben-Zaken

Haim

Zubidat

2013

Journal of Experimental Biology

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SUMMARYWe tested the effects of photoperiod, water and food availability on body mass, reproductive status and arginine vasopressin receptor 1A (Avpr1a) mRNA expression in males of desert-adapted golden spiny mice, Acomys russatus. In Experiment 1, males were acclimated to short-day (SD; 8h:16h light:dark) or long-day (LD; 16h:8h light:dark) photoperiods with either saline (control) or vasopressin treatment for 3weeks. The results of this experiment revealed that under control conditions, SD mice increased body mass by ~5% while LD mice decreased it by ~4%. SD photoperiod had no effect on reproductive status and leptin levels, whereas LD males increased testes mass and serum testosterone, but the photoperiod had no effect on leptin levels. Vasopressin administration decreased LD-induced reproductive enhancement. Because no consistent effect of SD treatment was found on reproductive status, Experiment 2 was carried out only on LD-acclimated males kept under 75% food restriction (decrease from ad libitum) with saline or leptin treatment. Body mass, testes mass, serum testosterone, leptin concentrations and Avpr1a mRNA expression were measured. Food restriction remarkably decreased body mass, with a more potent effect in leptin-treated males, showing enhanced reproductive status and a significant increase in serum leptin compared with controls. Avpr1a expression was significantly upregulated in LD, vasopressin-treated and food-restricted males, with higher levels in the hypothalamus compared with the testes. We conclude that in A. russatus, LD photoperiod interacts with water and food availability to advance reproductive responses. Avpr1a is suggested to integrate nutritional and osmotic signals to optimize reproduction by modulating reproductive and energetic neuroendocrine axes at the central level. The interaction between photoperiod and other environmental cues is of an adaptive value to desert-adapted small rodents for timing reproduction in unpredictable ecosystems such as extreme deserts.

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Centrally Administered Murine Leptin Stimulates Plasma Arginine-Vasopressin Secretion and Increases the Level of mRNA Expression in the Supraoptic Nucleus of Conscious Rats

Cited by 33 publications

References 32 publications

Centrally Administered Murine-Leptin Stimulates the Hypothalamus-Pituitary- Adrenal Axis through Arginine-Vasopressin

Centrally Administered Murine-Leptin Stimulates the Hypothalamus-Pituitary- Adrenal Axis through Arginine-Vasopressin

Food Intake-Induced Leptin Secretion Modulates Hypothalamo-Pituitary-Adrenal Axis Response and Hypothalamic Ob-Rb Expression to Insulin Administration

Long-day photoperiod interacts with vasopressin and food restriction to modulate reproductive status, and vasopressin receptor expression of male Golden spiny mice

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