GHS-R mRNA Research Articles

Effect of Complexation with Different Molecular Weights of Oat β-Glucan and Sea Buckthorn Flavonoid on the Digestion of Rice Flour.

The complex of oat β-glucan (OBG) and flavonoids hampered the digestion of starch-based food and retarded the blood glucose response; however, its effect on gastric emptying and its relative mechanism have not been thoroughly investigated. By using Fourier transform infrared (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), antioxidant ability, and enzymic inhibitory tests for the characterization and in vitro semi-dynamic digestion of complexes of OBG (high and low molecular weights) and sea buckthorn flavonoids, we found that the higher molecular weight complex (FU) exhibited stronger ABTS and DPPH radical scavenging abilities and higher α-glucosidase and α-amylase inhibition rates. Mice fed with rice flour with FU addition exhibited the slowest gastric emptying and intestinal propulsion rates and blood glucose rise and had the lowest activity of digestive enzymes and levels of insulin, ghrelin, motilin (MTL), and relevant gene (ghrelin and GHSR mRNA) expression than those in the control and low-molecular-weight groups. This study provided scientific data for the development of foods with delayed gastric rate and hypoglycemic index for specific populations.

Yunvjian Improves Glucose and Insulin Function in Diabetic Rats by Regulating Gastric Emptying Function.

Diet acts on the human body through digestion in the stomach and absorption in the intestines. Thus, the emptying of the stomach should be the focus of the research mechanism of the combined medicine and food treatment of diabetes. The emptying function of the stomach and the secretion of related hormones may be the key points of traditional Chinese medicine. In the clinic, Yunvjian is a famous traditional Chinese formula for preventing and curing diabetes. However, the pharmacological action and mechanism of Yunvjian are also need to be probe. To assess the effect of Yunvjian on glucose, insulin level and gastric emptying function and related hormones on high-fat diet combined with STZ-induced diabetic rats. High-fat diet combined with STZ was used to construct type 2 diabetes mellitus (T2DM) rats model and received a 4-week Yunvjian administration. The animals were divided into 6 groups, respectively, as the Control group, the DM group, the DM + Acarbose group, the DM + YNH group, and the DM + YNL group. Radionuclide single-photon emission computed tomography (SPECT) technology was used to observe the gastric emptying rate and half-empty time; blood was took to test fasting insulin, and then the insulin resistance index (HOMA-IR) was calculated; HE staining was performed to detect islets and gastric antrum, immunohistochemical staining was performed to detect the number and morphology of pancreatic β cells and gastric antrum Cajal cells, and the average optical density was calculated; the expression of ghrelin hormone in gastric antrum and serum was detected by ELISA and immunofluorescence; the expression of GHRS mRNA in gastric antrum was detected by RT-PCR method. Yunvjian could significantly improve the glucose level and insulin function of rats. Compared with the DM group, Yunvjian was beneficial to low fasting blood glucose (FBG) (P < 0.01), increased glucose tolerance, and improved islet function at the same time (P < 0.05). At the same time, compared with the DM group (25.02 ± 0.05, 44 ± 12.33), the emptying rate of the DM + YNH group was significantly faster (64.98 ± 0.12), and the half row time was shortened (26 ± 8.29, P < 0.05). The gastric ghrelin levels in each group of Yunvjian increased with different degrees compared with the DM group (616.2 ± 26.23), especially in the DM + YNH group (863.51 ± 23.76, P < 0.01). Correspondingly, the expression of gastric GHSR mRNA in the DM + YNH and DM + YNL groups increased significantly compared with the DM group (P < 0.01). Yunvjian can effectively control glucose and improve islet function, which may be closely related to its influence on gastric emptying function and related hormone secretion regulation.

The ghrelinergic system in zebrafish gonads is suppressed during food unavailability

Ghrelin is an appetite stimulatory peptide that regulates reproduction in vertebrates. The acylation of ghrelin by ghrelin-O-acyltransferase (Goat) is essential for most of its functions. The ghrelinergic system (ghrelin, ghrelin receptor [Ghsr] and Goat) is present in teleost fish ovary and testis. In this research, we determined the abundance of the ghrelinergic system mRNAs in different stages of follicle (oocyte) development in zebrafish ovary. The highest levels of preproghrelin mRNA were observed in the first stage of follicular development (previtellogenesis). Significantly low levels of preproghrelin mRNA were observed in stages 3II, 4 and 5 of the follicle development. Ghsr mRNA abundance remained unchanged at early stages of follicle development and decreased in stage 5 compared to other developmental stages. A significant decrease in preproghrelin and Ghsr mRNAs in the testis, and ghsr mRNA in the ovary of zebrafish deprived of food for 3 days were found. At 7 days food deprivation, preproghrelin, ghsr and goat mRNA in the ovary and preproghrelin and goat in the testis of zebrafish were significantly reduced. These results show that metabolic status modulates gonadal ghrelinergic system in zebrafish and provide support for a role for ghrelin in fish reproduction.

410 Mild Maternal Undernutrition Results in a Premature Neonatal Leptin Surge and Resistance in Male Offspring to a High Fat Diet

OBJECTIVES/GOALS: Maternal undernutrition, a form of malnutrition, can alter neonatal leptin signaling and result in metabolic dysfunction in adulthood. We developed a mild undernutrition model to relate more to societys nutritional challenges and to test the hypothesis that a shift in the neonatal leptin surge would result in sex-specific metabolic changes. METHODS/STUDY POPULATION: We studied pups from undernourished dams which were calorically restricted by 20% (CR20) from embryonic day 15 until postnatal day (PND) 21. We tested 216 offspring from 11 Fed dams and 13 undernourished dams (CR20), detecting a leptin surge in control fed progeny at PND11. At 3 months of age, offspring from 3 dams per maternal nutrient status were either exposed to a 45% high fat diet (HFD) or control diet (10% fat) for 16 weeks. Anterior pituitary hormones were analyzed in the pituitary and serum of neonates and adults. To determine the mechanism of the phenotype observed in male adult offspring on the HFD, single cell RNA sequencing was used to analyze the pituitary, fat and liver. RESULTS/ANTICIPATED RESULTS: Offspring of CR20 dams had an early leptin surge peaking at PND8 and GH levels at PND1 were higher in CR20 progeny. Weights of both male and female CR20 offspring were lower and body lengths were shorter than controls. As adults, Fed mice from both sexes had increased weight gain with HFD. However, although CR20 females gained weight on the HFD, male progeny from CR20 dams did not gain weight on the HFD and appeared protected from impact. We found sex-specific changes in pituitary Gh, Ghrhr, and Ghsr mRNA levels. Single cell RNA sequencing of pituitary, fat and liver of male offspring showed significant regulation of transcripts in fat of male offspring from Fed dams that was not found in CR20 males when compared to control fed mice. DISCUSSION/SIGNIFICANCE: Mild undernutrition causes a prematurely high leptin surge and sex-specific growth responses to a HFD, including resistance to a HFD in underfed males. Transcript analysis in fat of males resistant to HFD induced obesity may reveal mechanisms that provide protection against HFD induced weight gain.

Ghrelin-induced Food Intake, but not GH Secretion, Requires the Expression of the GH Receptor in the Brain of Male Mice.

Ghrelin stimulates both GH secretion and food intake. The orexigenic action of ghrelin is mainly mediated by neurons that coexpress agouti-related protein (AgRP) and neuropeptide Y (NPY) in the arcuate nucleus of the hypothalamus (ARH). GH also stimulates food intake and, importantly, ARHAgRP/NPY neurons express GH receptor (GHR). Thus, ghrelin-induced GH secretion may contribute to the orexigenic effect of ghrelin. Here, we investigated the response to ghrelin in male mice carrying GHR ablation specifically in neurons (brain GHR knockout [KO] mice) or exclusively in ARHAgRP/NPY neurons (AgRP GHR KO mice). Although brain GHR KO mice showed normal ghrelin-induced increase in plasma GH levels, these mutants lacked the expected orexigenic response to ghrelin. Additionally, brain GHR KO mice displayed reduced hypothalamic levels of Npy and Ghsr mRNA and did not elicit ghrelin-induced c-Fos expression in the ARH. Furthermore, brain GHR KO mice exhibited a prominent reduction in AgRP fiber density in the ARH and paraventricular nucleus of the hypothalamus (PVH). In contrast, AgRP GHR KO mice showed no changes in the hypothalamic Npy and Ghsr mRNAs and conserved ghrelin-induced food intake and c-Fos expression in the ARH. AgRP GHR KO mice displayed a reduced AgRP fiber density (~16%) in the PVH, but this reduction was less than that observed in brain GHR KO mice (~61%). Our findings indicate that GHR signaling in the brain is required for the orexigenic effect of ghrelin, independently of GH action on ARHAgRP/NPY neurons.

Mild Maternal Undernutrition Results in a Premature Neonatal Leptin Surge that Promotes Resistance in Male Offspring to a High Fat Diet

Malnutrition alters leptin signaling, resulting in dysregulation of pituitary somatotropes that may be sex-specific. We reported sex differences in acute fasting responses with reductions in serum leptin in males, but not females (1). Maternal undernutrition can also alter the neonatal leptin surge by blunting with 50% food deprivation (2), causing a premature surge with 30% food deprivation (3), and resulting in metabolic dysfunction in adulthood (2,3). We developed a milder undernutrition model to relate more closely to society’s nutritional challenges and to test the hypothesis that a shift in the neonatal leptin surge would result in sex-specific metabolic changes. Compared to paired ad libitum (Fed) dams, we studied pups from undernourished dams that were calorically restricted by 20% (CR20) from embryonic day 15 until postnatal day (PND) 21.We tested 216 offspring from 11 Fed dams and 13 undernourished dams (CR20), detecting a leptin surge in control fed progeny at PND11. CR20 offspring of both sexes had an early surge (PND8) that was 62% (P<0.0001) higher compared to offspring of Fed dams and was maintained at high levels until PND11. Interestingly, GH levels at PND1 were 354% (P<0.0001) higher in the CR20 progeny compared to controls. By PND16, serum IGF-1 levels in underfed pups were lower than levels in control pups (111364±71 vs 244145±135 pg/ml; P=0.0277). CR20 male weights were 13.1% lower (P<0.0001) and lengths were 8.4% shorter (P=0.0002) than controls by 8 weeks of age and did not recover. CR20 female weights were lower by 11% (P=0.0013) and lengths were shorter up to 3 weeks of age.At 3 months of age, offspring were exposed to a 45% HFD for 16 weeks, testing 54 pups from 3 dams per nutrient status. Fed mice from both sexes responded to the HFD with an average weight gain of 12.3g (P<0.0001) in females and 12.6g (P<0.0001) in males. Females from CR20 dams also gained weight (8.74g, P<0.0001) on the HFD, but was significantly lower than females from Fed dams (P=0.0362). Surprisingly, male progeny from CR20 dams did not respond to weight gain by HF feeding when compared to control fed males, appearing to be protected from impact.Sex-specific changes in pituitary Gh, Ghrhr, and Ghsr mRNA levels were as follows. Among CR20 males exposed to HFD, Ghsr mRNA increased by 64% (P=0.0154) when compared to control fed males. Among CR20 females, Gh expression was unchanged with HFD but Ghrhr expression was blunted by 54.7% (P=0.0363). However, Gh mRNA was reduced by 34% (P= 0.0265) when compared to control females on the HFD. Collectively, these data show that mild undernutrition causes a prematurely high leptin surge and sex-specific differences in growth and responses to a HFD, including a potential resistance to a HFD in underfed males.

Sex differences in somatotrope response to fasting: biphasic responses in male mice.

Anterior pituitary somatotropes are important metabolic sensors responding to leptin by secreting growth hormone (GH). However, reduced leptin signals caused by fasting have not always correlated with reduced serum GH. Reports show that fasting may stimulate or reduce GH secretion, depending on the species. Mechanisms underlying these distinct somatotrope responses to fasting remain unknown. To define the somatotrope response to decreased leptin signaling we examined markers of somatotrope function over different time periods of fasting. Male mice were fasted for 24 and 48 h, with female mice fasted for 24 h compared to fed controls ad libitum. Body weight and serum glucose were reduced in both males and females, but, unexpectedly, serum leptin was reduced only in males. Furthermore, in males, serum GH levels showed a biphasic response with significant reductions at 24 h followed by a significant rise at 48 h, which coincided with the rise in serum ghrelin levels. In contrast, females showed an increase in serum GH at 24 h. We then explored mechanisms underlying the differential somatotrope responses seen in males and observed that pituitary levels of Gh mRNA increased, with no distinction between acute and prolonged fasting. By contrast, the Ghrhr mRNA (encoding GH releasing hormone receptor) and the Ghsr mRNA (encoding the ghrelin receptor) were both greatly increased at prolonged fasting times coincident with increased serum GH. These findings show sex differences in the somatotrope and adipocyte responses to fasting and support an adaptive role for somatotropes in males in response to multiple metabolic signals.

Involvement of the GHSR in the developmental programming and metabolic disturbances induced by maternal undernutrition

The mismatch between maternal undernutrition and adequate nutrition after birth increases the risk of developing metabolic diseases. We aimed to investigate whether the hyperghrelinemia during maternal undernourishment rewires the hypothalamic development of the offspring and contributes to the conversion to an obese phenotype when fed a high-fat diet (HFD). Pregnant C57BL/6 J, wild type (WT) and ghrelin receptor (GHSR)−/− mice were assigned to either a normal nourished (NN) group, or an undernutrition (UN) (30% food restricted) group. All pups were fostered by NN Swiss mice. After weaning, pups were fed a normal diet, followed by a HFD from week 9. Plasma ghrelin levels peaked at postnatal day 15 (P15) in both C57BL/6 J UN and NN pups. Hypothalamic Ghsr mRNA expression was upregulated at P15 in UN pups compared to NN pups and inhibited agouti-related peptide (AgRP) projections. Adequate lactation increased body weight of UN WT but not of GHSR−/− pups compared to NN littermates. After weaning with a HFD, body weight and food intake was higher in WT UN pups but lower in GHSR−/− UN pups than in NN controls. The GHSR prevented a decrease in ambulatory activity and oxygen consumption in UN offspring during ad libitum feeding. Maternal undernutrition triggers developmental changes in the hypothalamus in utero which were further affected by adequate feeding after birth during the postnatal period by affecting GHSR signaling. The GHSR contributes to the hyperphagia and the increase in body weight when maternal undernutrition is followed by an obesity prone life environment.

High fat diet induced obesity alters endocannabinoid and ghrelin mediated regulation of components of the endocannabinoid system in nodose ganglia

BackgroundGhrelin and anandamide (AEA) can regulate the sensitivity of gastric vagal afferents to stretch, an effect mediated via the transient receptor potential vanilloid 1 (TPRV1) channel. High fat diet (HFD)-induced obesity alters the modulatory effects of ghrelin and AEA on gastric vagal afferent sensitivity. This may be a result of altered gastric levels of these hormones and subsequent changes in the expression of their receptors. Therefore, the current study aimed to determine the effects of ghrelin and AEA on vagal afferent cell body mRNA content of cannabinoid 1 receptor (CB1), ghrelin receptor (GHSR), TRPV1, and the enzyme responsible for the breakdown of AEA, fatty acid amide hydrolase (FAAH). MethodsMice were fed a standard laboratory diet (SLD) or HFD for 12wks. Nodose ganglia were removed and cultured for 14 h in the absence or presence of ghrelin or methAEA (mAEA; stable analogue of AEA). Relative mRNA content of CB1, GHSR, TRPV1, and FAAH were measured. ResultsIn nodose cells from SLD-mice, mAEA increased TRPV1 and FAAH mRNA content, and decreased CB1 and GHSR mRNA content. Ghrelin decreased TRPV1, CB1, and GHSR mRNA content.In nodose cells from HFD-mice, mAEA had no effect on TRPV1 mRNA content, and increased CB1, GHSR, and FAAH mRNA content. Ghrelin decreased TRPV1 mRNA content and increased CB1 and GHSR mRNA content. ConclusionsAEA and ghrelin modulate receptors and breakdown enzymes involved in the mAEA-vagal afferent satiety signalling pathways. This was disrupted in HFD-mice, which may contribute to the altered vagal afferent signalling in obesity.

Study on the influence of acupoints selection on ghrelin and GHSR expression in gastric fundus tissue of DGP rats

Objective: To explore the acupoint selection compatibility according to different departments and to study the influence on ghrelin and GHSR expression in the gastric fundus in rats with Diabetic Gastroparesis (DGP). Methods: Sixty male SPF SD rats were given adaptive feeding for one week and were randomly divided into a blank control group, a model group, the Zusanli and Zhongwan (ZZ) group, the Zusanli and Neiguan group (ZN), as well as the Zusanli and non-meridian acupoint (ZNA) group, with 12 rats in each group. Except for the blank group, the other 48 rats were used to establish a DGP model by using streptozotocin. Acupuncture therapy was performed from the end of the tenth week for an additional four weeks. Then the rats were sacrificed and the serum and gastric fundus tissues were collected. ELISA assay was used to detect the ghrelin content in the serum. The expression of ghrelin positive cells in the gastric fundus tissue was detected by immunohistochemistry. The expression of ghrelin and GHSR mRNA in the gastric fundus tissue was detected by real-time PCR. Results: Compared with the blank group, the food intake and the expression of ghrelin and GHSR mRNA in the gastric fundus tissue in the model group were significantly increased, while the small intestinal propulsion rate, the ghrelin content in the serum and the gray value of the gastric fundus were significantly decreased (P<0.05). Compared with the model group, the expression of ghrelin and GHSR mRNA in the gastric fundus tissue, the small intestinal propulsion rate, the ghrelin content in the serum and the gray value of the gastric fundus were significantly increased (P<0.05). Compared with the ZZ group, the food intake were significantly increased in the ZN and the ZNA groups (P<0.05), and the expression of ghrelin and GHSR mRNA in the gastric fundus tissue of rats were significantly increased (P<0.05) but the ghrelin content in the serum in ZN group was significantly decreased (P<0.05). Conclusions: The improvement of gastrointestinal motility in DGP by acupuncture therapy was associated with the ghrelin content in the serum and GHSR expression in the gastric fundus. The treatment effect of local acupoints compatibility was better than that of the distal acupoints compatibility, and the acupoint selection according to department was one of the main influencing factors of acupoints compatibility.

Recurrent miscarriage is associated with increased ghrelin mRNA expression in the endometrium- a case-control study

Ghrelin has been found to be expressed in the human endometrium. Emerging evidence links ghrelin and its receptor with the reproductive system. Certain associations between ghrelin and angiogenesis have also been established. The aim of this small case-control study was to quantify and compare the expression of mRNA encoding ghrelin, ghrelin receptor (GHS-R), vascular endothelial growth factor A (VEGF A) and its receptors (VEGFR1-3) in the endometrium of women with recurrent miscarriage compared to parous controls. Correlations between the expression of particular genes were also investigated. Endometrial samples were obtained during the secretory phase of the menstrual cycle from 15 women with a history of recurrent miscarriage (first trimester pregnancy loss without a known cause) and 10 healthy parous controls. Ghrelin, GHS-R, VEGF A and VEGFR1-3 mRNA expression was analyzed by quantitative RT-PCR. The expression of mRNA for ghrelin and VEGF A was significantly higher in the study group than the control group. In the control group, the expression of ghrelin mRNA was positively correlated with the expression of VEGF A and VEGFR1 mRNA. In the study group, no such associations were observed. These results show that the expression of mRNA for ghrelin and VEGF A may be increased in the endometrium of women with recurrent miscarriage thus suggesting that ghrelin may play a role in the pathogenesis of recurrent miscarriage.

Effect of electroacupuncture on gastric motility, expressions of ghrelin and GHSR mRNA in gastric antrum tissue of diabetic gastroparesis rats

Objective To explore the action mechanism of electroacupuncture (EA) in improving the gastric motility of rats with diabetic gastroparesis (DGP).

Ghrelin's control of food reward and body weight in the lateral hypothalamic area is sexually dimorphic

Ghrelin is a stomach-produced hormone that stimulates ingestive behavior and increases motivated behavior to obtain palatable foods. Ghrelin receptors (growth hormone secretagogue receptors; Ghsr) are expressed in the lateral hypothalamic area (LHA), and LHA-targeted ghrelin application increases ingestive behavior in male rodents. However, the effects of LHA ghrelin signaling in females are unexplored. Here we investigated whether LHA ghrelin signaling is necessary and sufficient for control of ingestive and motivated behavior for food in male and female rats. Ghrelin delivered to the LHA increased food intake and motivated behavior for sucrose in both male and female rats, whereas increased food-seeking behavior and body weight were only observed in females. Females had slightly higher Ghsr levels in the LHA compared to males, and importantly, acute blockade of the Ghsr in the LHA significantly reduced food intake, body weight, and motivated behavior for sucrose in female but not male rats. Chronic LHA Ghsr reduction in female rats achieved by RNA inference-mediated Ghsr knockdown, resulting in a 25% reduction in LHA Ghsr mRNA, abolished the reward-driven behavioral effects of LHA-targeted ghrelin, but was not sufficient to affect baseline food intake or food reward responding. Collectively we show that ghrelin acts in the LHA to alter ingestive and motivated behaviors in a sex-specific manner.

Influence of ghrelin on rat pituitary GH3 cell line proliferation

Introduction. Human ghrelin is the endogenous ligand of the growth hormone secretagogue receptor type 1a (GHSR1a). It is suggested that ghrelin is involved in pituitary adenomas pathogenesis. There are inconsistent data regarding the effect of ghrelin on cell proliferation. In this study the outcome of ghrelin in the rat pituitary adenoma GH3 cell line on morphology and proliferation ratio was evaluated. The ghrelin receptor (Ghsr) mRNA expression in GH3 cell line was established as well, because it was found that heterogeneous expression pattern characterized physiological and pathological conditions of tissues of different origin.Material and Methods. Suitable experimental model pituitary tumor (rat GH3 cell line) was stimulated with ghrelin in the final concentrations 10–12 M, 10–9 M and 10–6 M. Reverse transcription followed by real time polymerase chain reaction was used for ghrelin receptor gene transcript detection. The morphology as well as cell cycle of those cells were analyzed using Axio Vert.A1 Microscope (Zeiss) and BD FACSCalibur™ flow cytometer (Beckton Dickinson), respectively. The percentages of cells in the G0/G1, S, G2/M cycle phases were evaluated using the ModFit™ software (Verity Software, Inc., USA). Results. Ghsr mRNA presence was confirmed in GH3 cells. Ghrelin did not affect conspicuously GH3 cells morphology, however the ghrelin‑induced proliferation index increase was caused by both decline of G0/G1 phases cells count and increase those being in S+G2/M (p &lt; 0.05). Conclusions. In conclusion, this study indicates that ghrelin stimulates GH3 cells proliferation and may play role in pituitary tumorigenesis via an autocrine/paracrine pathway.

Influence of ghrelin on rat pituitary GH3 cell line proliferation

Introduction. Human ghrelin is the endogenous ligand of the growth hormone secretagogue receptor type 1a (GHSR1a). It is suggested that ghrelin is involved in pituitary adenomas pathogenesis. There are inconsistent data regarding the effect of ghrelin on cell proliferation. In this study the outcome of ghrelin in the rat pituitary adenoma GH3 cell line on morphology and proliferation ratio was evaluated. The ghrelin receptor (Ghsr) mRNA expression in GH3 cell line was established as well, because it was found that heterogeneous expression pattern characterized physiological and pathological conditions of tissues of different origin.Material and Methods. Suitable experimental model pituitary tumor (rat GH3 cell line) was stimulated with ghrelin in the final concentrations 10–12 M, 10–9 M and 10–6 M. Reverse transcription followed by real time polymerase chain reaction was used for ghrelin receptor gene transcript detection. The morphology as well as cell cycle of those cells were analyzed using Axio Vert.A1 Microscope (Zeiss) and BD FACSCalibur™ flow cytometer (Beckton Dickinson), respectively. The percentages of cells in the G0/G1, S, G2/M cycle phases were evaluated using the ModFit™ software (Verity Software, Inc., USA). Results. Ghsr mRNA presence was confirmed in GH3 cells. Ghrelin did not affect conspicuously GH3 cells morphology, however the ghrelin-induced proliferation index increase was caused by both decline of G0/G1 phases cells count and increase those being in S+G2/M (p &lt; 0.05). Conclusions. In conclusion, this study indicates that ghrelin stimulates GH3 cells proliferation and may play role in pituitary tumorigenesis via an autocrine/paracrine pathway.

Effect of Deletion of Ghrelin-O-Acyltransferase on the Pulsatile Release of Growth Hormone in Mice.

Ghrelin, a gut hormone originating from the post-translational cleavage of preproghrelin, is the endogenous ligand of growth hormone secretagogue receptor 1a (GHS-R1a). Within the growth hormone (GH) axis, the biological activity of ghrelin requires octanoylation by ghrelin-O-acyltransferase (GOAT), conferring selective binding to the GHS-R1a receptor via acylated ghrelin. Complete loss of preproghrelin-derived signalling (through deletion of the Ghrl gene) contributes to a decline in peak GH release; however, the selective contribution of endogenous acyl-ghrelin to pulsatile GH release remains to be established. We assessed the pulsatile release of GH in ad lib. fed male germline goat(-/-) mice, extending measures to include mRNA for key hypothalamic regulators of GH release, and peripheral factors that are modulated relative to GH release. The amount of GH released was reduced in young goat(-/-) mice compared to age-matched wild-type mice, whereas pulse frequency and irregularity increased. Altered GH release did not coincide with alterations in hypothalamic Ghrh, Srif, Npy or Ghsr mRNA expression, or pituitary GH content, suggesting that loss of Goat does not compromise canonical mechanisms that contribute to pituitary GH production and release. Although loss of Goat resulted in an irregular pattern of GH release (characterised by an increase in the number of GH pulses observed during extended secretory events), this did not contribute to a change in the expression of sexually dimorphic GH-dependent liver genes. Of interest, circulating levels of insulin-like growth factor (IGF)-1 were elevated in goat(-/-) mice. This rise in circulating levels of IGF-1 was correlated with an increase in GH pulse frequency, suggesting that sustained or increased IGF-1 release in goat(-/-) mice may occur in response to altered GH release patterning. Our observations demonstrate that germline loss of Goat alters GH release and patterning. Although the biological relevance of altered GH secretory patterning remains unclear, we propose that this may contribute to sustained IGF-1 release and growth in goat(-/-) mice.

The effects of streptozotocin-induced diabetes on ghrelin expression in rat testis: biochemical and immunohistochemical study.

Ghrelin is a hormone which has effects on the secretion of growth hormone, gastrointestinal system, cardiovascular system, cell proliferation and reproductive system. The present study we focused on the relation between ghrelin and GHS-R1a gene expression and the regulation of their expression in the testes of diabetic rats. 40 male Wistar albino rats were divided into four groups: control, and sampled 4, 8 and 12 weeks after induction of diabetes by streptozotocin (STZ) intraperitoneal injection (40 mg/kg). The rats were decapitated under ketamine anesthesia and their testes were removed. Blood was obtained from heart and serum follicle stimulating hormone (FSH), luteinizing hormone (LH), and testosterone levels were measured by ELISA. Tissue ghrelin and GHS-R mRNA levels were determined by qRT-PCR, while ghrelin protein expression was studied by immunohistochemistry. Histopathological damage scores were also assessed. Eight weeks after diabetes induction serum FSH level was increased, whereas LH and testosterone concentrations decreased. The ghrelin and GHS-R1a gene expression and ghrelin immunohistochemistry score first tended to increase after first four weeks of diabetes, and then tended to decrease. Ghrelin-immunopositive cells were detected in Leydig cells in all groups of rats, however, not in the germinal epithelium. Congestion of vessels and hemorrhage, formation of the vacuoles in spermatogonia and spermatocytes, desquamation of spermatids in the lumen and disorganization of seminiferous tubule germinal epithelium were observed in testis of all the diabetic rats. In addition, mean testicular biopsy score and mean seminiferous tubule diameter were getting lower in diabetic animals. Our results suggest that diabetes affects ghrelin expression in rat testis.

The Effects of Long-Term Diabetes on Ghrelin Expression in Rat Stomachs.

Ghrelin is ahormone which has effects on the secretion of growth hormone, the gastrointestinal system, the cardiovascular system, cell proliferation and the reproductive system. This study focused on relative ghrelin and GHS-R1a gene expression in the stomach of long-term diabetic rats. Atotal of 36 male Wistar albino rats were divided into four groups: acontrol group, one-month diabetic rats, two-month diabetic rats and three-month diabetic rats. Diabetes was induced by streptozotocin STZ (40 mg/kg i.p). The rats were decapitated under ketamine anesthesia and their stomach tissues were removed. Tissue ghrelin expression, ghrelin and GHS-RmRNA levels were then compared using immunohistochemistry and qRT-PCR. After one month of diabetes, the number of ghrelin-immunopositive cells decreased significantly compared to those of the control rats. However, the ghrelin-immunopositive cells increased numerically in the two- and three-month diabetic rats compared to those of the control rats. It was also observed that there were high levels of ghrelin mRNA in the one- and two-month diabetic rats, and asubsequent decrease of ghrelin mRNA levels in the three-month diabetic rats compared to the control rats. However, ghrelin receptor mRNA expression levels decreased in the one-month diabetic rats, and ghrelin levels subsequently increased in the two- and three-month diabetic rats compared to the control rats. The two- and three-month diabetic rats became cachectic due to the large amount of weight lost. The authors therefore concluded that ghrelin-immunopositive cells increased in these rats due to their cachectic state.

P.6.a.001 Serum ghrelin concentrations and expression of GHSR mRNA in the rat brain after chronic alcoholization and ethanol withdrawal

reported since only 35% of the sample answered ‘very much’. Considering availability the same value was reported for the answer ‘sometimes’ and ‘ much’ (25.8%). Conclusions: Promazine was the most frequently used drug when treating agitated elderly patients, regardless of their diagnosis. Other drugs were used less frequently and with very different preferences among different prescribers. A larger sample is needed to confirm our preliminary finding.

P.6.a.002 DNA damages and behaviour disorders in pups of rats exposed to alcohol in the antenatal period, and its correction by afobazole

Chemotherapy treatment can lead to delayed gastric emptying, early satiety, anorexia, nausea and vomiting, described collectively as the cancer-associated dyspepsia syndrome (CADS). Administration of ghrelin (GHRL), an endogenous orexigenic peptide known to stimulate gastric motility, has been shown to reduce the symptoms of CADS induced in relevant animal models with the potent chemotherapeutic agent, cisplatin. We examined the effects in the rat of cisplatin (6 mg/kg i.p.) treatment on the expression of GHRL and ghrelin receptor (GHSR) mRNAs in the hypothalamus and the stomach at a time-point (2 days) when the effects of cisplatin are pronounced. In addition, plasma levels of GHRL (acylated and total including des-acyl GHRL) were measured and the effect on these levels of treatment with the synthetic glucocorticoid dexamethasone (2 mg/kg s.c. bd.) was investigated. Cisplatin increased GHSR mRNA expression in the stomach (67%) and hypothalamus (52%) but not GHRL mRNA expression and increased the percentage of acylated GHRL (7.03 ±1.35% vs. 11.38 ± 2.40%) in the plasma. Dexamethasone reduced the plasma level of acylated GHRL and the percentage of acylated GHRL to values below those in animals treated with saline alone (7.03 ± 1.35% vs. 2.60 ±0.49%). Our findings support the hypothesis that an adaptive upregulation of the ghrelin receptor may occur during cancer chemotherapy-associated dyspepsia. This may have a role in defensive responses to toxic challenges to the gut. In addition, our results provide preliminary evidence for glucocorticoid modulation of plasma ghrelin levels.