Effects of peptidic growth hormone secretagogue receptor (GHS-R) antagonist [D-Lys3] on some of serum hormonal and biochemical parameters in Wistar rat model / Efeitos do antagonista [D-Lys3] do receptor do peptídeo secretagogo do hormônio do crescimento (GHS-R) sobre alguns parâmetros bioquímicos e hormonais séricos em um modelo em ratos Wistar

Objective : The present study investigated the effects of different dosages of a GHS-R antagonist [D-Lys3] on some serum hormonal (cortisol, T3 and T4) and biochemical parameters in a rat.Materials and methods : Thirty-six 60-day-old male rats were assigned to four treatments. [D-Lys3]-GHRP-6 solutions were infused via intraperitoneal injections. Blood was collected and analyzed.Results : The large dosages of a GHS-R antagonist (200 ng/kg BW) caused increases in cortisol, whereas no significant changes occurred when low dosages were injected. There were no significant changes in T3 and T4 following the administration of the GHS-R antagonist, but a considerable increase was observed in blood glucose levels of the groups (G50, G100, and G200 ng/kg BW). There was a significant increase in total protein when the greatest dose was administrated (G200 ng/kg BW). However, total cholesterol, triglycerides, and albumin showed no significant changes.Conclusions : Exogenous GHS-R antagonist can cause an increase in glucose and moderate increases in cortisol and total protein, yet it has no significant effect on T3 and T4 levels or on the concentrations of serum lipids. The effect of GHS-R antagonist is not completely adverse to the effects of ghrelin. Further molecular studies are necessary to identify the physiological effects of the peptidic GHS-R antagonist. Arq Bras Endocrinol Metab. 2014;58(3):288-91.

Objetivo : O presente estudo investigou os efeitos de diferentes doses do antagonista do GHS-R [D-Lys3] sobre alguns parâmetros hormonais (cortisol, T3 e T4) e bioquímicos em ratos.Materiais e métodos : Trinta e seis ratos machos com 60 dias de idade foram alocados para quatro tratamentos. Soluções de [D-Lys3]-GHRP-6 foram administradas por meio de injeções intraperitoneais e foram coletadas e analisadas amostras.Resultados : Doses altas de antagonista de GHS-R (200 ng/kg PC) levaram a aumento do cortisol, enquanto não houve diferença significativa quando foram injetadas doses baixas. Não houve alterações significativas em T3 e T4 depois da administração do antagonista do GHS-R, mas foi observado aumento considerável nos níveis de glicose sanguínea dos grupos (G50, G100 e G200 ng/kg PC). Houve aumento significativo na proteína total quando foi administrada a maior dose (G200 ng/kg PC), entretanto, não foram observadas alterações no colesterol total, nos triglicérides e na albumina.Conclusões : O antagonista do GHS-R exógeno pode causar aumento da glicose e aumento moderado do cortisol e proteína total, embora não haja efeitos significativos nos níveis de T3 e T4 ou na concentração de lipídios séricos. O efeito do antagonista de GHS-R não é completamente adverso aos efeitos da grelina. Devem ser feitos outros estudos moleculares para se identificar os efeitos fisiológicos do peptídeo antagonista do GHS-R. Arq Bras Endocrinol Metab. 2014;58(3):288-91.

Effect of intracerebrovascular injection of ghrelin on some of erythropoietic indicators in 42-day-old broiler chicken

Objective: To evaluate the erythropoietic indicators in 42-day-old broiler chicks following intracerebrovascular injection of exogenous rat ghrelin at 21 day of age. Methods: A total of 90 male chicks were divided into three experimental groups including three replicates (10 chicks for each replicate): group 1 without any ghrelin injection, group 2 subjected to intracerebrovascular injection of 0.5 mg ghrelin/kg b.w. and group 3 subjected to intracerebrovascular injection of 1.0 mg ghrelin/kg b.w. at 21 days of age. Results: Intracerebrovascular injection of 0.5 or 1.0 mg ghrelin/kg b.w. at 21 days of age did not have any significant effect on the measured erythropoietic indicators including red blood cell, hematocrit, haemoglobin, mean corpuscular volume, mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration. Conclusions:Intracerebrovascular injection of exogenous rat ghrelin does not have any considerable effect on erythropoietic activity of broiler chickens.

Effect of in ovo ghrelin administration on serum malondialdehyde level in newly-hatched chickens

Objective: To investigate effects of in ovo ghrelin administration on serum malondialdehyde (MDA) level in newly-hatched chickens. Methods: Fertilized eggs were divided into 7 groups: group T1 as control (without injection), group T2 (in ovo injected with 50 ng/egg ghrelin on day 5), group T3 (in ovo injected with 100 ng/egg ghrelin on day 5), group T4 (in ovo injected with 50 ng/egg ghrelin on day 10), group T5 (in ovo injected with 100 ng/egg ghrelin on day 10), group T6 (in ovo injected with solvent: 1% acetic acid, without ghrelin on day 5) and group T7 (in ovo injected with solvent without ghrelin on day 10). After hatching, serum MDA concentrations were determined. Results:Ghrelin administrated groups (T2, T3, T4 and T5) had lower serum MDA level in comparison with control group (T1) or solvent injected groups (T6 and T7). T2 and T3 (ghrelin injection on day 5) had significantly lower MDA concentrations (4.10 and 4.60 nmol/mL, respectively) in comparison with other groups. In T4 and T5, MDA levels were lower than T1, T6 and T7 (non-ghrelin administrated groups) (9.53 and 9.50 in comparison with 10.73, 10.03 and 10.13 nmol/mL) and were higher than T2 and T3. Conclusions: It can be concluded that in ovo administration of ghrelin can have anti-oxidative protection and reduce serum MDA level. Ghrelin administration on day 5 of incubation is more efficient.

Plasma Lipoprotein Profile in Newly Hatched Chicks Following in Ovo Ghrelin Administration.

Objective: The aim of this study was to investigation on effects of in ovo administrated exogenous ghrelin on plasma lipid profile in hatched broiler chicks. Methodology: 250 eggs were obtained from commercial broiler breeder (Ross 308 strain) farm. the eggs were divided into five experimental groups; T1 or eggs without any injection (control), T2 or eggs in ovo injected with 50ng ghrelin at embryonic day-5, T3 or eggs in ovo injected with 100ng ghrelin at embryonic day-5, T4 or eggs in ovo injected with 50ng ghrelin at embryonic day-10, and T5 or eggs in ovo injected with 100ng ghrelin at embryonic day-10. Similar in ovo experiments were done for all of injected groups on day-5 or -10. At end of incubation, blood samples from each group were collected following chick decapitation and analyzed for determination of plasma lipoprotein concentrations. Results: Exogenous ghrelin administration at different embryonic days couldn’t have any considerable effect on low density lipoprotein (LDL-C), very low density lipoprotein (VLDL-C) or high density lipoprotein (HDL)/LDL-C. Plasma HDL-C concentration had increase follow in ovo injection of 100ng ghrelin at day-5 (P<0.01) and had slight increase at day-10 (group T3 and T5). Conclusion: As conclusion, in ovo administration of 100ng ghrelin at embryonic day-5 could elevate plasma HDL-C concentrations of newly-hatched chicks without any significant effect on LDL-C, VLDL or HDL-LDL ratio.