The teleost Scatophagus argus is a species whose females grows faster than males.Growth hormone(gh)mRNA abundance in females pituitary is higher than that in males;however the mechanism underlining such differential i...The teleost Scatophagus argus is a species whose females grows faster than males.Growth hormone(gh)mRNA abundance in females pituitary is higher than that in males;however the mechanism underlining such differential is still unknown.Growth hormone(GH)is tightly associated with GH-releasing hormone(Ghrh)in vertebrates.In this study,Ghrh gene(ghrh)and its receptor gene,ghrhr,were isolated from S.argus.Tissue expression analysis showed that ghrh and ghrhr were mainly expressed in hypothalamus while ghrhr was expressed in pituitary and gh was predominantly expressed in pituitary.Twenty cultured S.argus individuals were used to compare ghrh,ghrhr and gh mRNA abundances,120 g and 181 g average weight for male(n=11)and female(n=9),respectively.Real-time PCR indicated that the ghrh and ghrhr mRNA abundances in male hypothalamus were significantly higher than those in female hypothalamus while that of gh mRNA abundance was significantly higher in female pituitary than in male pituitary.The ghrh and ghrhr mRNA abundances were significantly up-regulated in female hypothalamus 3 h after injection of 0.1 mg kg^-1 body weight Ghrh while pituitary ghrhr and gh mRNA abundances were not affected.In female hypothalamus,ghrh and ghrhr m RNA abundances were not affected at 6 h post-injection of 4 mg kg^-1 body weight 17α-methyltes-tosterone(17α-MT)or 17β-Estradiol(E2).In female pituitary,ghrhr m RNA abundance was down-regulated by 17α-MT while that of gh m RNA abundance was up-regulated by E2.Our findings indicated that E2,rather than Ghrh,plays an important role in up-regulating the expression of gh in female S.argus,which should aid to understand the sexual dimorphism of teleost growth.展开更多
Background Diabetic gastroparesis is a disabling condition with no consistently effective treatment. In normal animals, both ghrelin and its synthetic peptide, growth hormone releasing peptide 6 （GHRP-6）, increase g...Background Diabetic gastroparesis is a disabling condition with no consistently effective treatment. In normal animals, both ghrelin and its synthetic peptide, growth hormone releasing peptide 6 （GHRP-6）, increase gastric emptying. Thus, we investigated the potential therapeutic significance of ghrelin and GHRP-6 in diabetic guinea pigs with gastric motility disorders. Methods A diabetic guinea pig model was produced by intraperitoneal （i.p.） injection of streptozotocin （STZ, 280 mg/kg）. Diabetic guinea pigs were injected i.p. with ghrelin or GHRP-6 （10-100 μg/kg）, and the effects on gastric emptying were measured after intragastric application of phenol red. The effect of atropine or a growth hormone secretagogue receptor （GHS-R） antagonist, D-Lys^3-GHRP-6, on the gastroprokinetic effects of ghrelin or GHRP-6 （100 μg/kg） was also investigated. Further, the in vitro effects of ghrelin or GHRP-6 （0.01-10 μmol/L） on spontaneous or carbachol-induced contractile amplitude in gastric fundic circular strips taken from diabetic guinea pigs were examined. Growth hormone secretagogue receptor transcripts in the fundic strips of diabetic guinea pigs were detected by reverse transcriptase polymerase chain reaction （RT-PCR）. Results We established a guinea pig model of delayed gastric emptying. Ghrelin （20, 50, or 100 μg/kg） and GHRP-6 （20, 50, or 100 μg/kg） accelerated gastric emptying in diabetic guinea pigs with gastroparesis （n=6, P 〈0.05）. In the presence of atropine, which delayed gastric emptying, ghrelin and GHRP-6 （100 μg/kg） failed to accelerate gastric emptying （n=6, P 〈0.05）. D-Lys^3-GHRP-6 also delayed gastric emptying induced by the GHS-R agonist （n=6, P 〈0.05）. Ghrelin and GHRP-6 increased the carbachol-induced contractile amplitude in gastric fundic strips taken from diabetic guinea pigs （n=6, P〈0.05）. RT-PCR confirmed the presence of GHS-R mRNA in the strip preparations. Conclusions Ghrelin and GHRP-6 increased gastric emptying in diab展开更多
基金the Key Project of ‘Blue Granary Science and Technology Innovation’ of the Ministry of Science and Technology (No. SQ2018 YFD090006)the National Natural Science Foundation of China (Nos. 31702326 and 41706174)+8 种基金the Natural Science Foundation of Guangdong Province (Nos. 2016A03 0313743, 2017A030313101 and 2018B030311050)the Department of Education of Guangdong Province (Nos. 2018KTSCX090 and 2018KQNCX106)the Guangdong Provincial Special Fund For Modern Agriculture Industry Technology Innovation Teams (No. 2019KJ149)the Zhanjiang Science and Technology Bureau (No. 2016A03017)Guangdong Ocean University Natural Science Research Program (2015 and 2016)the Project of Provincial Key Platform and Major Scientific Research of Colleges and Universities in Guangdong (No. 2015KTSCX058)the Sail Projects of Guangdong (2014.1)the Marine Fishery Science and Technology Extension Projects of Guangdong (Nos. A201408A06 and A201608B01)the Program for Scientific Research Start-Up Funds of Guangdong Ocean University
文摘The teleost Scatophagus argus is a species whose females grows faster than males.Growth hormone(gh)mRNA abundance in females pituitary is higher than that in males;however the mechanism underlining such differential is still unknown.Growth hormone(GH)is tightly associated with GH-releasing hormone(Ghrh)in vertebrates.In this study,Ghrh gene(ghrh)and its receptor gene,ghrhr,were isolated from S.argus.Tissue expression analysis showed that ghrh and ghrhr were mainly expressed in hypothalamus while ghrhr was expressed in pituitary and gh was predominantly expressed in pituitary.Twenty cultured S.argus individuals were used to compare ghrh,ghrhr and gh mRNA abundances,120 g and 181 g average weight for male(n=11)and female(n=9),respectively.Real-time PCR indicated that the ghrh and ghrhr mRNA abundances in male hypothalamus were significantly higher than those in female hypothalamus while that of gh mRNA abundance was significantly higher in female pituitary than in male pituitary.The ghrh and ghrhr mRNA abundances were significantly up-regulated in female hypothalamus 3 h after injection of 0.1 mg kg^-1 body weight Ghrh while pituitary ghrhr and gh mRNA abundances were not affected.In female hypothalamus,ghrh and ghrhr m RNA abundances were not affected at 6 h post-injection of 4 mg kg^-1 body weight 17α-methyltes-tosterone(17α-MT)or 17β-Estradiol(E2).In female pituitary,ghrhr m RNA abundance was down-regulated by 17α-MT while that of gh m RNA abundance was up-regulated by E2.Our findings indicated that E2,rather than Ghrh,plays an important role in up-regulating the expression of gh in female S.argus,which should aid to understand the sexual dimorphism of teleost growth.
基金This study was supported by a grant from National Natural Science Foundation of China （No. 30400429）.
文摘Background Diabetic gastroparesis is a disabling condition with no consistently effective treatment. In normal animals, both ghrelin and its synthetic peptide, growth hormone releasing peptide 6 （GHRP-6）, increase gastric emptying. Thus, we investigated the potential therapeutic significance of ghrelin and GHRP-6 in diabetic guinea pigs with gastric motility disorders. Methods A diabetic guinea pig model was produced by intraperitoneal （i.p.） injection of streptozotocin （STZ, 280 mg/kg）. Diabetic guinea pigs were injected i.p. with ghrelin or GHRP-6 （10-100 μg/kg）, and the effects on gastric emptying were measured after intragastric application of phenol red. The effect of atropine or a growth hormone secretagogue receptor （GHS-R） antagonist, D-Lys^3-GHRP-6, on the gastroprokinetic effects of ghrelin or GHRP-6 （100 μg/kg） was also investigated. Further, the in vitro effects of ghrelin or GHRP-6 （0.01-10 μmol/L） on spontaneous or carbachol-induced contractile amplitude in gastric fundic circular strips taken from diabetic guinea pigs were examined. Growth hormone secretagogue receptor transcripts in the fundic strips of diabetic guinea pigs were detected by reverse transcriptase polymerase chain reaction （RT-PCR）. Results We established a guinea pig model of delayed gastric emptying. Ghrelin （20, 50, or 100 μg/kg） and GHRP-6 （20, 50, or 100 μg/kg） accelerated gastric emptying in diabetic guinea pigs with gastroparesis （n=6, P 〈0.05）. In the presence of atropine, which delayed gastric emptying, ghrelin and GHRP-6 （100 μg/kg） failed to accelerate gastric emptying （n=6, P 〈0.05）. D-Lys^3-GHRP-6 also delayed gastric emptying induced by the GHS-R agonist （n=6, P 〈0.05）. Ghrelin and GHRP-6 increased the carbachol-induced contractile amplitude in gastric fundic strips taken from diabetic guinea pigs （n=6, P〈0.05）. RT-PCR confirmed the presence of GHS-R mRNA in the strip preparations. Conclusions Ghrelin and GHRP-6 increased gastric emptying in diab
