BACKGROUND： Leptin may regulate reproductive function via release of hypothalamic neuropeptide Y. However, it is unknown whether this regulatory effect is limited to the hypothalamus. OBJECTIVE： To detect the effect...BACKGROUND： Leptin may regulate reproductive function via release of hypothalamic neuropeptide Y. However, it is unknown whether this regulatory effect is limited to the hypothalamus. OBJECTIVE： To detect the effect of different dosages of leptin on luteinizing hormone （LH） and follicle stimulating hormone （FSH） secretion from in vitro cultured rat anterior pituitary cells. DESIGN： Contrast study based on cells. SETTING： This study was performed in the Basic Institute of Chengde Medical College, Chengde City, Hebei Province, China from March to June 2007. MATERIALS： Eighteen female Wistar rats of three months of age, weighing 200-220 g, and of clean grade were used. Leptin was provided by Peprotech Company, DMEM culture medium by Invitrogen Company, and the radioimmunological kit by Beijing Zhongshan Jinqiao Biotechnology Co., Ltd. METHODS： Three glandular organs were regarded as one group for culture of anterior pituitary cells. In the control group, saline was added to the culture medium instead of leptin. In the leptin group, leptin was prepared into different concentrations of 1×10^-12, 1×10^-11, 1×10^-9, 1×10^-7, and 1×10^-6 mol/L for stimulation of cultured cells. The culture supernatant was obtained at three hours after additional of saline/leptin. MAIN OUTCOME MEASURES： Contents of LH and FSH were detected by radioimmunology. RESULTS： Following leptin stimulation, LH release increased with increasing concentrations of leptin up to 1×10^-9 mol/L, where LH release peaked. LH release then progressively decreased with increasing leptin concentrations （P 〈 0.01）. LH release in the leptin （1×10^-12, 1×10^-11, 1×10^-7, and 1×10^-6 mol/L） groups was significantly higher than that in the control group （P 〈 0.01）. FSH content in the leptin （1×10^-11, 1×10^-9, and 1×10^-7 mol/L） groups was significantly higher than that in the control group （P 〈 0.01）. CONCLUSION： Leptin can directly affect pituitary tissue to promote the secretion of LH and FSH in a dose-dependent manner.展开更多
BACKGROUND：Leptin preserves reproductive functions by stimulating hypothalamic-pituitary-gonadal axis activities at different levels.Some interneurons play an important role in leptin regulation of the gonadal axis.I...BACKGROUND：Leptin preserves reproductive functions by stimulating hypothalamic-pituitary-gonadal axis activities at different levels.Some interneurons play an important role in leptin regulation of the gonadal axis.It remains uncertain whether leptin regulates reproductive functions by activating proopiomelanocortin （POMC） neurons.OBJECTIVE：To investigate leptin effects on secretory function of the neuroendocrine-gonadal axis by activating POMC neurons and to observe and verify the relationship between leptin effects and various time points.DESIGN,TIME AND SETTING：The randomized,controlled,animal study was performed at the Basic Institute of Chengde Medical University and the Research Room of Reproductive Immunology of National Research Institute for Family Planning from June to September 2008.MATERIALS：Leptin （Peprotech,USA）,a-melanocyte stimulating hormone and rabbit anti-POMC polyclonal antibody （SC-20148） （Santa Cruz Biotechnology,USA）,follicle stimulating hormone,luteinizing hormone,and gonadotropin releasing hormone enzyme-labeled immunosorbent assay （ELISA） kit （ADL,USA） were used in the present study.METHODS：A total of 60 healthy,female,adult,Wistar rats received 17 （3-estradiol for 5 consecutive days at 15 days after ovariectomy.The rats were randomly assigned to physiological saline （n= 35）,leptin （n = 35）,and a-melanocyte stimulating hormone （n = 20） groups.MAIN OUTCOME MEASURES：Changes in gonadotropin releasing hormone,luteinizing hormone,and follicle stimulating hormone were compared following intraventricular injection of physiological saline,leptin,and a-melanocyte stimulating hormone at various time points.Changes in POMC mRNA and protein expression in the hypothalamus were measured following physiological saline and leptin injection via the lateral ventricle.RESULTS：Compared to the physiological saline group,leptin and a-melanocyte stimulating hormone affected secretion in the hypothalamus-pituitary axis.Leptin affected secretion of gonadotropin releasing hormone,luteinizing hormone,and follicle stimulating hormone,whereas a-melanocyte stimulating hormone inhibited secretion of these hormones.Compared to the physiological saline group,POMC mRNA expression was significantly increased in the hypothalamus at 2 and 4 hours after leptin injection （P〈 0.05）,but expression recovered to physiological saline group levels at 6 hours after injection （P 〉 0.05）.POMC protein expression was significantly increased in the hypothalamus at 4 and 6 hours after leptin injection （P〈 0.05）.CONCLUSION：Leptin affects secretory function of the neuroendocrine-gonadal axis through combined effects on POMC neurons and other pathways.Results suggested that the regulatory effects of POMC neurons were later compared to other neurons.展开更多
文摘BACKGROUND： Leptin may regulate reproductive function via release of hypothalamic neuropeptide Y. However, it is unknown whether this regulatory effect is limited to the hypothalamus. OBJECTIVE： To detect the effect of different dosages of leptin on luteinizing hormone （LH） and follicle stimulating hormone （FSH） secretion from in vitro cultured rat anterior pituitary cells. DESIGN： Contrast study based on cells. SETTING： This study was performed in the Basic Institute of Chengde Medical College, Chengde City, Hebei Province, China from March to June 2007. MATERIALS： Eighteen female Wistar rats of three months of age, weighing 200-220 g, and of clean grade were used. Leptin was provided by Peprotech Company, DMEM culture medium by Invitrogen Company, and the radioimmunological kit by Beijing Zhongshan Jinqiao Biotechnology Co., Ltd. METHODS： Three glandular organs were regarded as one group for culture of anterior pituitary cells. In the control group, saline was added to the culture medium instead of leptin. In the leptin group, leptin was prepared into different concentrations of 1×10^-12, 1×10^-11, 1×10^-9, 1×10^-7, and 1×10^-6 mol/L for stimulation of cultured cells. The culture supernatant was obtained at three hours after additional of saline/leptin. MAIN OUTCOME MEASURES： Contents of LH and FSH were detected by radioimmunology. RESULTS： Following leptin stimulation, LH release increased with increasing concentrations of leptin up to 1×10^-9 mol/L, where LH release peaked. LH release then progressively decreased with increasing leptin concentrations （P 〈 0.01）. LH release in the leptin （1×10^-12, 1×10^-11, 1×10^-7, and 1×10^-6 mol/L） groups was significantly higher than that in the control group （P 〈 0.01）. FSH content in the leptin （1×10^-11, 1×10^-9, and 1×10^-7 mol/L） groups was significantly higher than that in the control group （P 〈 0.01）. CONCLUSION： Leptin can directly affect pituitary tissue to promote the secretion of LH and FSH in a dose-dependent manner.
基金the Science Foundation of Hebei Provincial Science & Technology Department,No.08276101D-20the Science Foundation of Hebei Provincial Education Department,No. 2008301the Science and Technology Research and Development Project of Chengde City of Hebei Province,No. 200922061
文摘BACKGROUND：Leptin preserves reproductive functions by stimulating hypothalamic-pituitary-gonadal axis activities at different levels.Some interneurons play an important role in leptin regulation of the gonadal axis.It remains uncertain whether leptin regulates reproductive functions by activating proopiomelanocortin （POMC） neurons.OBJECTIVE：To investigate leptin effects on secretory function of the neuroendocrine-gonadal axis by activating POMC neurons and to observe and verify the relationship between leptin effects and various time points.DESIGN,TIME AND SETTING：The randomized,controlled,animal study was performed at the Basic Institute of Chengde Medical University and the Research Room of Reproductive Immunology of National Research Institute for Family Planning from June to September 2008.MATERIALS：Leptin （Peprotech,USA）,a-melanocyte stimulating hormone and rabbit anti-POMC polyclonal antibody （SC-20148） （Santa Cruz Biotechnology,USA）,follicle stimulating hormone,luteinizing hormone,and gonadotropin releasing hormone enzyme-labeled immunosorbent assay （ELISA） kit （ADL,USA） were used in the present study.METHODS：A total of 60 healthy,female,adult,Wistar rats received 17 （3-estradiol for 5 consecutive days at 15 days after ovariectomy.The rats were randomly assigned to physiological saline （n= 35）,leptin （n = 35）,and a-melanocyte stimulating hormone （n = 20） groups.MAIN OUTCOME MEASURES：Changes in gonadotropin releasing hormone,luteinizing hormone,and follicle stimulating hormone were compared following intraventricular injection of physiological saline,leptin,and a-melanocyte stimulating hormone at various time points.Changes in POMC mRNA and protein expression in the hypothalamus were measured following physiological saline and leptin injection via the lateral ventricle.RESULTS：Compared to the physiological saline group,leptin and a-melanocyte stimulating hormone affected secretion in the hypothalamus-pituitary axis.Leptin affected secretion of gonadotropin releasing hormone,luteinizing hormone,and follicle stimulating hormone,whereas a-melanocyte stimulating hormone inhibited secretion of these hormones.Compared to the physiological saline group,POMC mRNA expression was significantly increased in the hypothalamus at 2 and 4 hours after leptin injection （P〈 0.05）,but expression recovered to physiological saline group levels at 6 hours after injection （P 〉 0.05）.POMC protein expression was significantly increased in the hypothalamus at 4 and 6 hours after leptin injection （P〈 0.05）.CONCLUSION：Leptin affects secretory function of the neuroendocrine-gonadal axis through combined effects on POMC neurons and other pathways.Results suggested that the regulatory effects of POMC neurons were later compared to other neurons.
