KISS-1/GPR54基因及其在生殖中的作用

KISS-1及其受体GPR54基因对青春期的正常启动具有重要作用。青春期开始前后, 动物下丘脑中KISS-1和GPR54 mRNA水平很高, Kisspeptins(KISS-1基因产物)通过激活GPR54增加促性腺激素的释放, KISS-1基因的表达受性腺类固醇激素的调控。GPR54基因突变可以导致人和鼠的特发性促性腺激素分泌不足性腺机能减退症和促性腺激素依赖性性早熟。文章还介绍了KISS-1、GPR54基因的结构、表达、多态性以及和其它生殖调控因子之间的相互关系。     

神经内分泌因子调控鱼类生殖和生长的相互作用

脊椎动物的生长与生殖活动有着密切的联系并相互作用。许多调节生长和代谢活动的内分泌因子对青春期或者性腺的发育产生影响。同样,调节生殖活动的许多激素亦同时对生长和代谢产生影响。近年来,我们和其他学者对鱼类生长和生殖的神经内分泌调节的相互作用进行了研究,主要的进展是：①在促进性腺的激素影响生长方面,发现促性腺激素释放激素（ＧｎＲＨ）和多巴胺都能和脑垂体生长激素细胞的特异性受体结合而刺激生长激素释放,并能     

Kisspeptin调控鱼类生殖内分泌的研究进展

Kisspeptin是近10年新发现的调控动物生殖内分泌的关键因子,是kiss基因所编码的多肽产物,属神经内分泌肽类激素,为G蛋白偶联受体54(GPR54)的内源性配体。Kisspeptin具多个功能性的分子结构形态,在鱼类中,主要结构形式为Kisspeptin-10肽。Kisspeptin/GPR54系统在生殖中具重要功能。该文综合现有研究资料,就Kisspeptin在鱼类生殖内分泌调控中的概况、Kisspeptin神经元在鱼脑中的分布和定位、鱼类Kisspeptin分子的多态性、Kisspeptin调控鱼生殖内分泌的功能多样性、Kisspeptin调控鱼类生殖内分泌的机制、Kisspeptin的分子进化以及Kisspeptin和其他功能分子对鱼类生殖内分泌的协同调控进行了初步阐述,同时对Kisspeptin在鱼类生殖内分泌调控中的研究进行了展望。     

蛙类促性腺激素释放激素的研究

蛙类促性腺激素释放激素的研究李远友林浩然（中山大学生物系广州５１０２７５）关键词促性腺激素释放激素特性作用蛙促性腺激素释放激素（ＧｎＲＨ）是脊椎动物脑垂体促性激素（ＧｔＨ）合成和释放的主要调节者,在生殖功能神经激素调控中起关键作用。近年来,哺乳类和...     

促性腺激素释放激素受体及其基因表达调控

促性腺激素释放激素（ＧｎＲＨ,ＬＨＲＨ）在体内的重要功能是由ＧｎＲＨ受体介导的。ＧｎＲＨ受体是近年神经分内分泌和生殖生物学研究的热点之一,本文从ＧｎＲＨ受体的分子结构,ＧｎＲＨ受体基因表达调控,ＧｎＲＨ受体分布及表达,调节ＲｎＲＨ受体的因素以及ＧｎＲＨ受体介导的细胞信号转导等几个方面对ＧｎＲＨ受体近年来的研究进展进行了综述,对ＧｎＲＨ受体的研究,将有助于人们进一步了解ＧｎＲＨ受体在生殖调节和恶性肿     

鱼类内分泌学研究的动向

鱼类内分泌学的研究是整个比较内分泌学的重要组成部份。1981年12月在香港举行的第九届国际比较内分泌学学术会议,在下丘脑-脑垂体,神经分泌物,促性腺激素释放激素,生殖内分泌,促性腺激素,甲状腺,肾上腺皮质,生长激素和催乳激素,类固醇激素,性分化,性腺成熟,排卵和产卵,季节性周期和节律,代谢的内分泌调节,钙调节,血管活动激素,前列腺素等专题学术报告和讨论组中,关于鱼类内分泌的研究论文都占相当比例。       

动物季节性繁殖分子调控机理研究进展

动物季节性发情繁殖涉及下丘脑-垂体-性腺轴系统复杂的神经内分泌过程,并受光照周期等环境因素的影响。褪黑激素则作为光周期信号分子调控动物季节性繁殖活动。近年来研究发现,对GnRH分泌有重要影响的Kiss1/GPR54系统既受褪黑激素的调控又受到性腺类固醇激素反馈调节,Kiss1/GPR54系统很可能是调控动物季节性繁殖的关键因子;同时动物季节性繁殖很可能还存在一条涉及TSH-DIO2/DIO3系统的逆向调控通路,该系统同样显著影响GnRH合成释放并受褪黑激素调控。文章就褪黑激素中心信号,特别是Kiss1/GPR54和TSH-DIO2/DIO3系统对繁殖季节性调控的最新研究进展进行综述。     

性激素反馈调节下丘脑ARC和AVPV中kisspeptin-GPR54信号通路的核团差异

下丘脑-垂体-性腺（HPG）轴是调控生殖系统的发育和功能的重要内分泌系统。下丘脑中促性腺激素释放激素（GnRH）神经元,能够接收各种神经传导物质和神经调节物质的信号输入,引起HPG轴的级联反应。下丘脑弓状核(ARC）和前腹侧脑室周围核团(AVPV）中的kisspeptin-GPR54信号通路,可以调控GnRH的分泌和释放,影响性腺激素的分泌。近年来研究发现,性激素能够对下丘脑kisspeptin-GPR54信号通路产生反馈调节,且具有核团差异性。本文就性激素在下丘脑ARC和AVPV中对kisspeptin-GPR54信号通路反馈调节的差异性进行了综述,探讨下丘脑中不同核团对性激素刺激作用产生的不同反应。     

鱼类内分泌学研究的动向

鱼类内分泌学的研究是整个比较内分泌学的重要组成部份。1981年12月在香港举行的第九届国际比较内分泌学学术会议,在下丘脑-脑垂体,神经分泌物,促性腺激素释放激素,生殖内分泌,促性腺激素,甲状腺,肾上腺皮质,生长激素和催乳激素,类固醇激素,性分化,性腺成熟,排卵和产卵,季节性周期和节律,代谢的内分泌调节,钙调节,血管活动激素,前列腺素等专题学术报告和讨论组中,关于鱼类内分泌的研究论文都占相当比例。     

G蛋白偶联受体119——治疗糖尿病的新靶点

G蛋白偶联受体119(GPR119)与激动剂结合后,通过cAMP信号转导途径,促进葡萄糖依赖性胰岛素和肠肽激素的分泌,是新一代的治疗2型糖尿病药物靶点。本文对GPR119的组织学分布、生理学作用、内源性配体以及小分子激动剂作一简要的介绍。     

Distribution of iron in pig placenta (Sus scrofa dom. L.)

Iron distribution was studied in pig placentae between 21 day till the end of pregnancy (113) with the use of histochemical and cytochemical methods and X-ray microanalysis. Iron content was measured in fetal and maternal part of the placenta with chemical methods. Iron presence was confirmed in maternal and fetal erythrocytes, cells and secretion of uterine glands and trace amount in trophoblast lining regular areolae. No significant differences were found in iron content in fetal and maternal part of the placenta throughout the entire studied period. With the applied histochemical method of iron determination according to Perls, potassium ferrocyanide also adsorbs in sites where mucopolysaccharides are present, in which iron presence has not been detected with the use of X-ray microanalysis.     

Measurement of human fetal blood flow.

Real-time B-mode ultrasonography was combined with a pulsed Doppler ultrasound technique for transcutaneous measurement of human fetal blood flow in the aorta and intra-abdominal part of the umbilical vein. The target vessel was located and its diameter measured in the two-dimensional real-time image. The pulsed Doppler transducer was attached to the real-time transducer at a fixed angle. By processing the Doppler shift signals the instrument estimated the mean and maximum blood velocities and the integral under the velocity curves. This permitted calculation of the blood flow. The method was applied to 26 fetuses in normal late pregnancies. Mean blood flow in the descending part of the fetal aorta based on maximum velocity was 191 ml/kg/min. Mean flow in the intra-abdominal part of the umbilical vein was 110 ml/kg/min. This method of measurement is non-invasive and opens new perspectives in studying fetal haemodynamics.     

Serum prolactin levels in fetal and neonatal hamsters and the relationship to maternal levels.

Immunoreactive prolactin was measured by RIA in 13.5-15.5 day gestation fetal and 0.5-3.5 day neonatal hamster serum and found to significantly reflect rises and falls in maternal levels. On the average, fetal and neonatal levels were 37% of maternal prolactin serum levels. 125I-PRL injected into 13.5-15.5 day pregnant hamsters was demonstrated to cross the placenta and enter fetal circulation. Ten min after injection, fetal serum levels were calculated to be an average of 3.9% of the radioactivity recorded in maternal serum. There is a strong possibility that fetal prolactin serum levels may be, at least in part, attributed to a maternal source.     

The fine structure of the thymus of the fetal and neonatal monkey (Macaca mulatta)

Summary The morphologic features of the fetal and neonatal thymus were investigated by light and electron microscopy to determine developmental changes. Primitive epithelial cells differentiate into reticular epithelial cells, medullary epithelial cells, elongated epithelial cells, Hassall's corpuscles and cysts. Thymocytes first appear at 50 days fetal age and the number of thymocytes is amplified from 75–150 days fetal age. Minor differences between the fetal thymus of the monkey and that of other species were observed. Possible functions for the various cellular components of the fetal monkey thymus are discussed.This research was supported in part by grants 5-F3-CA-28, 793-02 and FR-0167 from the National Institutes of Health.     

Development of primary culture of ovine fetal hepatocytes for studies of amino acid metabolism and insulinlike growth factors

Summary We report the development and characterization of a system of primary culture of ovine fetal hepatocytes to aid in the understanding of the cellular regulation of fetal growth and metabolism with emphasis on amino acid metabolism and insulinlike growth factor gene expression and to allow comparison to in vivo studies. Hepatocytes were isolated from late gestation fetal lambs by in situ perfusion and collagenase digestion utilizing occlusion of the ductus venosus to limit intrahepatic shunting. Hepatocytes were cultured in media modified to mimic fetal concentrations of glucose, lactate, and amino acids. Ovine fetal hepatocytes in primary culture maintain the pattern of fetal amino acid production and utilization seen across the fetal liver in vivo. Specifically, there is a net production of serine and a net utilization of glycine. Cultured ovine fetal hepatocytes specifically increase tritiated thymidine incorporation in response to insulin and insulinlike growth factor II (IGF-II). IGF-II mRNA abundance is high and IGF-I mRNA is low in cultured ovine fetal hepatocytes as in the fetal sheep liver in vivo. These data demonstrate the successful isolation of ovine fetal hepatocytes that retain some of the characteristics of the ovine fetal liver while maintained in short-term culture. Supported in part by grants #HD20761, DK 35836, IP30 HD 27827, and HD 00781 from the National Institutes of Health, Bethesda, MD.     

Nervous system of the extraembryonic organs of the white rat fetus

Nervous apparatuses of the fetal membranes have been studied in white rats on the 18th-19th days of embryogenesis. Experimental hypoxia, novocaine and potassium chloride solutions effect ensure better revealing of the nervous system elements. At supravital staining with mythelene blue and at impregnation with silver nitrate, nervous fibers are revealed in the distal part of the umbilical cord and in the placental chorional plate. In the labyrinth part of the placenta certain nervous terminals are revealed. In the amnion certain nervous fibers and terminals are found both in the connective tissue and in the epithelium. On the omphaloplacenta vessels numerous nervous apparatuses are detected. A conclusion is made that at the end of embryogenesis the fetal membranes in the white rats are abundantly innervated. This demonstrates nervous regulation of the fetal membranes functions and of interrelationships of the fetus and the maternal organism.     

Fetal circulation during epidural analgesia for caesarean section.

Fetal blood flow was examined during epidural analgesia in six women with uncomplicated pregnancies undergoing elective caesarean section. A non-invasive, ultrasonic technique was used to measure blood flow in the fetal descending aorta and intra-abdominal part of the umbilical vein before induction of analgesia with etidocaine and bupivacaine and 15 and 30 minutes afterwards. No appreciable change in fetal blood flow was observed.     

Fetal breathing and development of control of breathing

Technical advances during the last several decades have greatly facilitated research into fetal physiology and behavior, specifically fetal breathing (FB). Breathing movements have been demonstrated in the fetuses of every mammalian species investigated and appear to be part of normal fetal development. In this review we focus on the methods of measuring FB and on some of the problems associated with these measurements and their interpretation. We also review fetal behavior, the role of the peripheral and central chemoreceptors in spontaneous FB, the fetal respiratory response to hypercapnia and hypoxia, and the transition to continuous breathing at birth. It is clear that in many ways the control of breathing movements in utero differs from that after birth. In particular, inhibitory influences are much more prominent before than after birth. Possibly this is due to the unique fetal situation, in which conservation of energy may be more important than any advantage breathing activity imparts to the fetus.     

Graphic monitoring of labour.

The parturograph is a composite record designed for the monitoring of fetal and maternal well-being and the progress of labour. It permits the early recognition of abnormalities and pinpoints the patients who would benefit most from intervention. Observations are made from the time of admission of the mother to the caseroom and recorded graphically. Factors assessed include fetal heart rate, maternal vital signs and urine, cervical dilatation, descent of the presenting fetal part, and frequency, duration and intensity of uterine contractions.