Neither intravenous nor intracerebroventricular administration of obestatin affects the secretion of GH, PRL, TSH and ACTH in rats

Yamamoto, Daisuke; Ikeshita, Nobuko; Daito, Rie; Herningtyas, Elizabeth Henny; Toda, Keizo; Takahashi, Kentaro; Iida, Keiji; Takahashi, Yutaka; Kaji, Hidesuke; Chihara, Kazuo; Okimura, Yasuhiko

doi:10.1016/j.regpep.2006.09.001

Cited by 77 publications

(57 citation statements)

References 10 publications

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“…nor i.c.v. administration of OBS affected ACTH and corticosterone secretion (13,14). Our studies also demonstrated that OBS infusion into rats with a regenerating adrenal cortex does not change plasma aldosterone and corticosterone concentrations.…”

Section: Discussionsupporting

confidence: 63%

“…In this regard, the stimulating (either the direct or indirect) effect of GHREL on CRH, ACTH and glucocorticoid hormone secretion is well documented, while the role of OBS is still disputable. Only limited data indicate that neither intravenous nor intracerebroventricular administration of OBS affects the secretion of ACTH and corticosterone in rats (13,14).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Ghrelin and obestatin inhibit enucleation-induced adrenocortical proliferation in the rat

Ruciński

Trejter²,

Ziółkowska³

et al. 2010

Int J Mol Med

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Abstract. Studies involving the role of ghrelin (GHREL) in regulating the proliferative activity of various cell types have obtained variable results depending primarily on the experimental model applied. It was recently reported that neither GHREL nor obestatin (OBS) affected the proliferative activity of cultured rat adrenocortical cells. In view of the conflicting results, we investigated the effects of GHREL and OBS on the proliferative activity of rat adrenocortical cells in a model of bilateral enucleation-induced adrenocortical regeneration in the rat. Rats were sacrificed 5 or 8 days after surgery. Twenty-four hours before being sacrificed, the appropriate groups were infused with 3 nmol GHREL or OBS/100 g. The mitotic index was assessed using the stachmokinetic method with vincristine. In comparison with intact rats, expression levels of ppGHREL, BAX, JUN-B and JUN-C genes were notably higher in regenerating adrenals, and neither GHREL nor OBS infusion affected these levels. Expression levels of the GHS-R, GPR39v2 and FOS genes were affected neither by adrenal enucleation nor GHREL or OBS infusion. Expression of only two studied genes, GPR39v1 and EGR1, was regulated by OBS. In the regenerating adrenal glands, GPR39v1 and EGR1 mRNA levels were higher than the levels in intact animals. GHREL infusion had no effect while OBS infusion notably stimulated GPR39v1 mRNA levels in the regenerating adrenal gland and evoked an opposite effect on EGR1 mRNA. OBS administration resulted in a potent decrease in the mitotic index of the studied cells, an effect found at both days 5 and 8 of the experiment. GHREL exerted a similar effect only at day 5 of adrenocortical regeneration. Neither GHREL nor OBS had an effect on blood aldosterone concentrations. GHREL infusion lowered plasma corticosterone concentration at day 5 but not 8 of the experiment, while OBS administration was ineffective. Thus, this study is the first to demonstrate that, in vivo, both GHREL and OBS inhibit the growth of the regenerating adrenal cortex. Moreover, the data suggest that the effect of OBS might be, at least in part, mediated by the EGR1 pathway known to be critical in cell proliferation.

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Section: Discussionsupporting

confidence: 63%

Section: Introductionmentioning

confidence: 99%

Ghrelin and obestatin inhibit enucleation-induced adrenocortical proliferation in the rat

Ruciński

Trejter²,

Ziółkowska³

et al. 2010

Int J Mol Med

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“…Neither intravenous nor intracerebroventricular administration of obestatin affects the secretion of prolactin, TSH and ACTH in rats [13,111,125,158,162]. On the other hand, a recent report provides evidence indicating that obestatin effects are functionally opposite on anxiety to that of ghrelin, while both these related peptides increase memory retention [22].…”

Section: Other Effectsmentioning

confidence: 97%

“…Most studies showed that neither intravenous nor intracerebroventricular administration of obestatin affects the secretion of GH in rats [13,111,125,158,162]. Nevertheless, a recent study showed that obestatin, in some conditions, can inhibit exogenous ghrelin action on GH release [164].…”

mentioning

confidence: 99%

Ghrelin, des-acyl ghrelin and obestatin: Three pieces of the same puzzle

2008

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a b s t r a c tThe major active product of ghrelin gene is a 28-amino acid peptide acylated at the serine 3 position with an octanoyl group, called simply ghrelin. Ghrelin has a multiplicity of physiological functions, affecting GH release, food intake, energy and glucose homeostasis, This suggests the existence of a novel endocrine system with multiple effector elements which not only may have opposite actions but may regulate the action of each other. In this review, we summarize the steps which lead to the production of the different ghrelin gene products and examine the most significant differences between them in terms of structure and actions.

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“…The initial claim of obestatin role on inhibition of food intake, body weight gain, satiety signalling, gastric emptying and intestinal motility in rodents, through the activation of the GPR39 receptor, has not been easily replicated [2,14,15]. Moreover, Yamamoto et al showed that the intracerebroventricular injection of obestatin did not have a stimulating effect of the pituitary hormones secretions (plasma GH, PRL, ACTH and TSH levels) despite the presence of GPR39 in the pituitary [39]. Furthermore, it was demonstrated that ghrelin is synthesized by cardiomyocytes and has a direct effect on its viability, however Iglesias et al did not find any relevant metabolic or viability effects of obestatin [20].…”

Section: Discussionmentioning

confidence: 99%