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Faculty of Pharmaceutical Sciences, Josai University, 1-1, Keyaki-dai, Saitama 350-02, Japan
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Faculty of Pharmaceutical Sciences, Josai University, 1-1, Keyaki-dai, Saitama 350-02, Japan
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Faculty of Pharmaceutical Sciences, Josai University, 1-1, Keyaki-dai, Saitama 350-02, Japan
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Faculty of Pharmaceutical Sciences, Josai University, 1-1, Keyaki-dai, Saitama 350-02, Japan
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Faculty of Pharmaceutical Sciences, Josai University, 1-1, Keyaki-dai, Saitama 350-02, Japan
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Faculty of Pharmaceutical Sciences, Josai University, 1-1, Keyaki-dai, Saitama 350-02, Japan
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role in growth regulation and energy homeostasis. A large amount of acylated bio-active ghrelin, the only peripheral orexigenic peptide identified so far, is present in the stomach ( Kojima et al. 1999 , Ariyasu et al. 2001 , Sakata et al
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a few days of postnatal life ( Masseyeff et al . 1975 , Germain et al . 1978 ). In this study, it was hypothesized that the stomach might be a main organ to produce E 2 after diminishing plasma estrogen binding proteins and that the gastric E 2
Department of Anatomy, Showa University School of Medicine, Tokyo 142-8555, Japan
Discovery Research Laboratories, Pharmaceuticals Research Division, Takeda Chemical Industries, Ibaraki 300-4293, Japan
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Department of Anatomy, Showa University School of Medicine, Tokyo 142-8555, Japan
Discovery Research Laboratories, Pharmaceuticals Research Division, Takeda Chemical Industries, Ibaraki 300-4293, Japan
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Department of Anatomy, Showa University School of Medicine, Tokyo 142-8555, Japan
Discovery Research Laboratories, Pharmaceuticals Research Division, Takeda Chemical Industries, Ibaraki 300-4293, Japan
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Department of Anatomy, Showa University School of Medicine, Tokyo 142-8555, Japan
Discovery Research Laboratories, Pharmaceuticals Research Division, Takeda Chemical Industries, Ibaraki 300-4293, Japan
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Department of Anatomy, Showa University School of Medicine, Tokyo 142-8555, Japan
Discovery Research Laboratories, Pharmaceuticals Research Division, Takeda Chemical Industries, Ibaraki 300-4293, Japan
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Department of Anatomy, Showa University School of Medicine, Tokyo 142-8555, Japan
Discovery Research Laboratories, Pharmaceuticals Research Division, Takeda Chemical Industries, Ibaraki 300-4293, Japan
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Department of Anatomy, Showa University School of Medicine, Tokyo 142-8555, Japan
Discovery Research Laboratories, Pharmaceuticals Research Division, Takeda Chemical Industries, Ibaraki 300-4293, Japan
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Department of Anatomy, Showa University School of Medicine, Tokyo 142-8555, Japan
Discovery Research Laboratories, Pharmaceuticals Research Division, Takeda Chemical Industries, Ibaraki 300-4293, Japan
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Department of Anatomy, Showa University School of Medicine, Tokyo 142-8555, Japan
Discovery Research Laboratories, Pharmaceuticals Research Division, Takeda Chemical Industries, Ibaraki 300-4293, Japan
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Department of Anatomy, Showa University School of Medicine, Tokyo 142-8555, Japan
Discovery Research Laboratories, Pharmaceuticals Research Division, Takeda Chemical Industries, Ibaraki 300-4293, Japan
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Department of Anatomy, Showa University School of Medicine, Tokyo 142-8555, Japan
Discovery Research Laboratories, Pharmaceuticals Research Division, Takeda Chemical Industries, Ibaraki 300-4293, Japan
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Department of Anatomy, Showa University School of Medicine, Tokyo 142-8555, Japan
Discovery Research Laboratories, Pharmaceuticals Research Division, Takeda Chemical Industries, Ibaraki 300-4293, Japan
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rats, including the stomach and intestine ( Fuji et al. 2002 ). NPW mRNA is expressed in the stomach, but a cellular source has yet to be identified ( Tanaka et al. 2003 ). In this study, we investigated the cellular source of NPW in the rat, mouse
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considered that the serum E 2 level is involved in stomach and liver functions. Cholestasis induced by bile duct ligation (BDL) causes an (up to threefold) increase in serum E 2 levels in male and female rats ( Chen et al . 1995 , 1998 ). Furthermore
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Introduction Ghrelin, a 28-amino acid peptide with an n -octanoyl modification, was originally discovered in human and rat stomach as an endogenous ligand for the growth hormone secretagogue receptor (GHS-R; Kojima et al . 1999 ). Ghrelin is
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Ghrelin, a 28 amino acid peptide, has recently been isolated from the rat stomach as an endogenous ligand for the GH secretagogue receptor. The fact that administration of ghrelin, centrally or peripherally, stimulates both food intake and GH secretion suggests that stomach ghrelin has an important role in the growth of rats. We used immunohistochemistry and radioimmunoassay to determine the age at which ghrelin-immunostained cells begin to appear in the rat stomach. Ghrelin-immunoreactive cells were found to be expressed in the fetal stomach from pregnancy day 18. The number of ghrelin-immunoreactive cells in the fetal stomach increased as the stomach grew. The amount of ghrelin in the glandular part of the rat stomach also increased, in an age-dependent manner, from the neonatal stage to adult. Eight hours of milk restriction significantly decreased the ghrelin concentration in the stomachs of 1-week-old rats, and increased the ghrelin concentration in their plasma. Administration of ghrelin to 1- and 3-week-old rats increased plasma GH concentrations. The daily subcutaneous administration of ghrelin to pregnant rats from day 15 to day 21 of pregnancy caused an increase in body weight of newborn rats. In addition, daily subcutaneous administration of ghrelin to neonatal rats from birth advanced the day of vaginal opening from day 30.7+/-0.94 to day 27.9+/-0.05. These results suggest that ghrelin may be involved in neonatal development.
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Subcutaneous injection of cortisol (10 μg/g body wt daily for 5 days) into normal neonatal rats increased the activity of stomach pepsinogen after day 5. l-Thyroxine (T4; 0·2 μg/g body wt daily for 5 days) alone did not affect the activity but it somewhat enhanced the effect of cortisol. Even before day 5, when no effect of cortisol alone was observed, T4 plus cortisol increased pepsinogen activity. In adrenalectomized, thyroidectomized neonatal rats, injection of cortisol alone did not induce enzyme activity but cortisol together with T4 did induce it. Moreover, the increase in pepsinogen activity was depressed in rats thyroidectomized on day 10 but not in those thyroidectomized on day 15. These results suggest that T4 does not have a direct effect on the stomach but plays an important role in making the stomach responsive to glucocorticoids, resulting in increased pepsinogen activity.
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Ghrelin was recently isolated from the rat stomach as an endogenous ligand for the GH secretagogue receptor. Although it is well known that a large amount of ghrelin is produced in the gastrointestinal tract, developmental changes in ghrelin mRNA expression and differentiation of ghrelin-immunopositive (ghrelin-ip) and mRNA-expressing (ghrelin-ex) cells in the stomach have not been elucidated. In this study, we therefore investigated the changes in ghrelin mRNA expression levels and in the numbers of ghrelin-ip and -ex cells in the stomachs of 1- to 8-week-old male and female rats by Northern blot analysis, immunohistochemistry and in situ hybridization. Northern blot analysis showed that the level of weak ghrelin mRNA expression was low in the postnatal period but then increased in a dimorphic pattern, i.e. transient stagnation at 4 weeks in the male rats and at 5 weeks in the female rats. The number of ghrelin-ip and ghrelin-ex cells also increased after birth, and more numerous ghrelin cells were found in female rats than in male rats, and this finding was confirmed by Northern blot analysis. Ghrelin-ip and -ex cells first appeared in the glandular base of the fundic gland and then they were found in the glandular base and the glandular neck at 3 weeks of age, suggesting that the distribution of ghrelin cells is extended from the glandular base to the glandular neck during the postneonatal development period. This is the first report on detailed changes in postneonatal ghrelin expression level and in the number of ghrelin cells in the rat stomach. The sexual dimorphism of ghrelin expression and ghrelin cell differentiation suggest that ghrelin plays an important physiological role in the stomach.
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Ghrelin, a 28-amino-acid peptide, has recently been isolated from the rat stomach as an endogenous ligand for the GH secretagogue receptor. We have reported previously that central or peripheral administration of ghrelin stimulates food intake, and the secretion of GH and gastric acid in rats. In the present study, we investigated how much endogenous centrally released ghrelin is involved in the control of food intake and body weight gain. We also examined the profile of ghrelin secretion from the stomach by RIA using two kinds of anti-ghrelin antiserum, one raised against the N-terminal ([Cys(12)]-ghrelin[1-11]) region and one raised against the C-terminal ([Cys(0)]-ghrelin [13-28]) region of the peptide. The former antibody recognizes specifically ghrelin with n- octanoylated Ser 3 (acyl ghrelin), and does not recognize des-acyl ghrelin. The latter also recognizes des-acyl ghrelin (i.e. total ghrelin). Intracerebroventricular treatment with the anti-ghrelin antiserum against the N-terminal region twice a day for 5 days decreased significantly both daily food intake and body weight. Des-acyl ghrelin levels were significantly higher in the gastric vein than in the trunk. Either fasting for 12 h, administration of gastrin or cholecystokinin resulted in increase of both acyl and des-acyl ghrelin levels. The ghrelin levels exhibited a diurnal pattern, with the bimodal peaks occurring before dark and light periods. These two peaks were consistent with maximum and minimum volumes of gastric content respectively. These results suggest that (1) endogenous centrally released ghrelin participates in the regulation of food intake and body weight, (2) acyl ghrelin is secreted from the stomach, (3) intestinal hormones stimulate ghrelin release from the stomach, and (4) regulation of the diurnal rhythm of ghrelin is complex, since ghrelin secretion is augmented under conditions of both gastric emptying and filling.
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3 residue is essential for ligand–receptor interaction. GHSR1a is the only receptor specific for acylated ghrelin that has been identified so far ( Kojima & Kangawa 2005 ). Although ghrelin is synthesized in many tissues, including stomach, pancreas
