催产素免疫反应神经元在鸡下丘脑的定位——PAP法研究

应用免疫组化PAP法(非标记抗体过氧化物酶-抗过氧化物酶法)研究了鸡下丘脑催产素(Oxytocin,OT)免疫反应阳性神经元的分布.结果,OT阳性神经元存在于下丘脑室旁核各亚核、视前室旁核、视上核、视前大细胞核、下丘脑外侧核、室周核、室周弓状核,在下丘脑背侧区、视前外侧区和丘脑背外侧核也有零星的OT阳性神经元,视上背侧交叉和正中隆起存在大量的OT阳性纤维和纤维末梢.此外,还观察到视前区和下丘脑前部脑基底表面以及视上核的外缘有OT阳性神经元和纤维(?)达脑的外表,在第三脑室室管膜上存在OT阳性神经元,室旁核的OT阳性细胞突起伸入到室管膜上或突出于第三脑室室腔。结果表明,OT阳性神经元在下丘脑的分布较广泛,OT向脑脊液的释放可能是多途径的.     

羔羊丘脑下部催产素的免疫组化定位

采用免疫组织化学技术中的链霉素抗生物素-过氧化酶(streptaridin-peroxidase，SP)法，对羔羊丘脑下部催产素(oxytocin，OT)神经元的定位及分布进行了研究。结果表明，丘脑下部分泌OT的神经元主要分布在室旁核和视上核，在环核、视上弥散核、弓状核、室周核、穹窿周核、丘脑下部前区、丘脑下部外侧区、丘脑下部后核和乳头体各核团等也有一定数量的阳性神经元；阳性神经纤维仅见于室旁核、视上弥散核、视上核和交叉上核，在正中隆起第三脑室附近有较多数量的阳性神经纤维。观察结果提示，OT在羔羊丘脑下部分布广泛，且丘脑下部OT经神经垂体、第三脑室、血管3条途径释放，经血液循环最终作用于靶细胞而发挥生理作用。     

Ghrelin免疫反应阳性神经元在鸡脑中的定位分布、发育性变化及禁食对其影响

本试验应用免疫组织化学方法和显微图像分析技术,研究了鸡脑Ghrelin免疫反应阳性神经元的定位分布,分析了2、16、30、44、58日龄鸡下丘脑Ghrelin免疫反应阳性神经元的发育性变化规律,并探讨了30日龄鸡分别禁食12、24、48h及重新采食4h对下丘脑Ghrelin免疫反应阳性神经元的影响。结果表明,在下丘脑弓状核、室旁核、内侧核、室周区、内侧区、外侧区,丘脑卵圆核、圆核,中脑丘中央灰质层、红核,脑桥前庭腹外侧核,小脑内侧核、小脑皮质颗粒层,大脑皮质多形细胞层等,均可观察到Ghrelin免疫反应阳性神经元;随着日龄的增长,下丘脑主要核团中的Ghrelin免疫反应阳性神经元的数量增多,免疫反应强度增强,但细胞密度下降;在禁食条件下,下丘脑Ghrelin免疫反应阳性神经元的免疫反应强度减弱,细胞密度下降。     

青年期广西本地水牛下丘脑催产素的免疫组化定位

为研究青年期广西本地水牛催产素能神经元的表达特点,试验采用免疫组织化学技术中的PicTureTM二步法对广西本地水牛催产素神经元的定位及分布进行了研究.结果表明:下丘脑分泌催产素的神经元主要分布在室旁核、视上核和弓状核,在视前内侧核、视交叉上核、下丘脑前核、下丘脑后核、背内侧核、腹内侧核和乳头体核等核团也有一定数量的阳性神经元;阳性神经纤维仅见于室旁核、弓状核、乳头体核,在正中隆起第三脑室室管膜附近有较多数量的阳性神经纤维.观察结果提示:下丘脑催产素经神经垂体、第三脑室、血管3条途径释放;不同种属动物下丘脑催产素存在差异.     

促性腺激素释放激素在妊娠牦牛下丘脑主要核团中的表达

为了研究促性腺激素释放激素(GnRH)在妊娠期牦牛下丘脑主要核团中的表达,研究其与牦牛妊娠期调控的关系。运用免疫组化ABC法和图像分析软件Image-Pro Plus 6.0对妊娠期牦牛下丘脑主要核团中GnRH的表达情况进行研究。结果表明:在下丘脑中,GnRH神经元主要分布在下丘脑前核(AH)、乳头体内侧核(MMN)、腹内侧核(VMN)、弓状核(ARC)和室旁核(PVN)等核团。在核团间,GnRH阳性产物的表达面积(S)及累积光密度(IOD)值存在差异,(SAHSMMNSVMNSARCSPVN和IODAHIODMMNIODVMNIODARCIODPVN);妊娠期的表达量高于非妊娠期的,推测这些核团中的GnRH神经元对妊娠期激素的调控发挥重要作用。     

成年发情期奶山羊下丘脑催产素及其mRNA的表达

应用免疫组织化学SP法和原位杂交法研究了催产素（oxytocin，OT）及OT mRNA在成年发情期奶山羊下丘脑中的分布和表达。结果，OT免疫反应阳性细胞主要分布在视上核和室旁核，在视上弥散核、弓状核、室周核和乳头体各核团也存在免疫阳性神经元；在室旁核、视上弥散核、正中隆起和第三脑室附近有较多数量的强阳性神经纤维，在交叉上核有少量阳性神经纤维。在下丘脑23个核团（区）中均能检测出OT mRNA的阳性细胞。结果表明，OT和OT mRNA在下丘脑中分布广泛，且OT可能通过轴突传递和血液运输，将OT mRNA合成的OT运送到别的核团；OT在奶山羊发情过程中发挥了重要作用。     

发情周期中奶山羊下丘脑-垂体-卵巢轴催产素的免疫组化定位

用免疫组化ABC法,对发情周期中奶山羊下丘脑-垂体-卵巢轴催产素(OT)分布进行了观察研究.结果表明,下丘脑中分泌OT的神经元主要分布在室旁核和视上核,在穹窿周核、腹内侧核、腹外侧核、交叉上核、背内侧核、乳头体、下丘脑外侧区、下丘脑前核等核团也有一定数量的阳性神经元;阳性神经纤维仅见于室旁核、下丘脑前核、视上核等少数核团,在正中隆起和第3脑室室周可见到一定数量的阳性神经纤维.在垂体前叶未见到OT免疫反应阳性产物,自垂体柄和正中隆起的一侧可见到平行排列的OT阳性神经纤维断续地延伸至神经部.卵巢的卵泡及间质未见OT免疫阳性反应,,在黄体组织中存在数量较多的免疫反应阳性细胞,阳性细胞主要呈圆形、卵圆形,小梁两侧及黄体中央近腔区域的阳性细胞呈长梭形,有相当数量的阳性细胞具有突起.连续切片HE染色对照观察显示,黄体中OT主要由大黄体细胞产生,但小黄体细胞也存在OT免疫阳性反应.     

鸡下丘脑加压素免疫反应神经元的分布——PAP法研究

鸡加压素(VP)免疫反应神经元分布于视上核、室旁核的中部和后部、视上交叉核、视前大细胞核、室周弓状核、下丘脑外侧核和室周核,正中隆起、视上背侧交叉和隔内侧区存在大量的VP阳性纤维末梢.在第三脑室室管膜和脑基底神经胶质板上也存在VP阳性神经元.同时发现室旁核、室周核、室周弓状核及视前大细胞核的VP阳性神经元有突起伸入到第三脑室室管膜或突出于脑室腔,视上核的VP阳性神经元也有突起投射至脑基底神经胶质板上或伸至蛛网膜下腔.据此认为,VP的释放是多途径的.     

发情周期中奶山羊下丘脑—垂体—卵巢轴催产素的免疫组化定位

用免疫组化ABC法，对发情周期中奶山羊下丘脑—全体—卵巢轴催产素(OT)分布进行了观察研究。结果表明，下丘脑中分泌OT的神经元主要分布在室旁核和视上核，在穿窿周核、腹内侧核、腹外侧核、交叉上核、背内侧核、乳头体、下丘脑外侧区、下丘脑前核等核团也有一定数量的阳性神经元；阳性神经纤维仅见于室旁核、下丘脑前核、视上核等少数核团，在正中隆起和第3脑室室周可见到一定数量的阳性神经纤维。在全体前叶未见到OT免疫反应阳性产物，自垂体柄和正中隆起的一例可见到平行排列的OT阳性神经纤维断续地延伸至神经部。卵巢的卵泡及间质未见OT免疫阳性反应，在黄体组织中存在数量较多的免疫反应阳性细胞，阳性细胞主要呈圆形、卵圆形，小梁两侧及黄体中央近腔区域的阳性细胞呈长梭形，有相当数量的阳性细胞具有突起。连续切片HE染色对照观察显示，黄体中OT主要由大黄体细胞产生，但小黄体细胞也存在OT免疫阳性反应。     

GnRH在妊娠期黄牛下丘脑—垂体—卵巢轴中的表达

旨在研究促性腺激素释放激素(GnRH)在妊娠期黄牛下丘脑—垂体—卵巢轴中的表达,探索其与妊娠的关系。运用免疫组化ABC法和图像分析软件Image-ProPlus6.0对妊娠期黄牛下丘脑、垂体和卵巢组织中GnRH的表达情况进行研究。结果表明:(1)在下丘脑中,GnRH阳性神经元主要分布于下丘脑前核(AH)、乳头体内侧核(MMN)、腹内侧核(VMN)、弓状核(ARC)及室旁核(PVN),其中AH和MMN阳性产物分布面积(S)和累计光密度(IOD)值均较大(SAHSMMNSVMNSARCSPVN和IODAHIODMMNIODVMNIODARCIODPVN;P0.001);(2)在腺垂体中,存在大量GnRH阳性细胞,而神经垂体中仅有GnRH阳性纤维;(3)在卵巢中,GnRH阳性产物分布在妊娠黄体、卵泡颗粒细胞及间质中。结果提示,在下丘脑各核团中,AH和MMN的GnRH可能对维持黄牛妊娠起主导作用,而垂体和卵巢中GnRH可能是通过自分泌和旁分泌方式与相关激素协同作用来维持妊娠黄牛的激素平衡及内环境稳态等。     

Influences of season and artificial photoperiod on stallions: pituitary and testicular responses to exogenous GnRH

Effects of season and photoperiod on the anterior pituitary gland and testes were studied by responses to exogenous GnRH. Stallions were assigned to one of three treatments: 1) control, exposed to natural day length; 2) S-L, 8 h of light and 16 h dark (8:16) for 20 wk beginning July 16, 1982 then 16:8 from December 2, 1982 until March 5, 1984; or 3) S-S, 8:16 from July 16, 1982 until March 5, 1984. Approximately every 8 wk, stallions were administered GnRH (2 micrograms/kg BW) and blood was sampled at 20-min intervals for 2 h before and 8 h after GnRH administration. Concentrations of LH, FSH and testosterone were determined. Baseline concentrations (mean of pre-GnRH samples) of all hormones fluctuated seasonally (P less than .05), but only LH and testosterone displayed seasonal changes (P less than .05) in maximum response to GnRH (highest concentration above baseline after GnRH). The FSH response to GnRH was not affected (P greater than .05) by season, photoperiod or the season X treatment interaction. Exposure of S-L stallions to 16:8 in December resulted in early recrudescence of baseline concentrations of LH, FSH and testosterone. Maximum concentration of testosterone in response to GnRH was stimulated by 16:8, but the increase in baseline LH concentrations in S-L stallions was not associated with an increase in maximum LH response to GnRH. Seasonal patterns of baseline concentrations of FSH and testosterone and maximum LH response to GnRH in S-S stallions were similar to those for control stallions.(ABSTRACT TRUNCATED AT 250 WORDS)     

Changes in the messenger RNA expressions of the endothelin-1 and angiotensin systems in mature follicles of the superovulated bovine ovary

The aim of the present study was to examine the messenger RNA expressions of the endothelin and angiotensin systems during the periovulatory phase in gonadotrophin releasing hormone (GnRH)-treated cows. Ovaries were collected by transvaginal ovariectomy (n=5 cows/group), and the follicles (n=5, one follicle/cow) were classified into the following groups: before GnRH administration (control, before LH surge), 3-5 h after GnRH (during LH surge), 10 h after GnRH; 20 h after GnRH, 25 h after GnRH (peri-ovulation), and early corpus luteum (CL) (Days 2-3). Expression of mRNA was investigated using quantitative real-time PCR. The expression of angiotensin converting enzyme (ACE) mRNA significantly decreased immediately after onset of the LH surge and remained at low levels. The levels of angiotensin II receptor type 1 (AT1R) and type 2 (AT2R) expression during the periovulatory period significantly decreased compared with other periods. The concentration of angiotensin II in follicular fluid began to increase 10 h after GnRH treatment and further increased as ovulation approached. The level of ET-1 mRNA significantly decreased 10 h after GnRH treatment compared with the levels before GnRH treatment and those of the early CL period. The expression of ETR-A and ETR-B mRNA during the periovulatory period were lower than in other periods. The expression of ECE-1 mRNA began to decrease in the LH surge period and significantly decrease in the periovulatory period compared with other periods. These results suggest that the vasoactive peptides angiotensin and endothelin may be associated with final maturation of follicles.     

单色光对肉鸡睾丸形态结构的影响

采用LED（Light-emitting diodes）灯作为光源,比较单色光对雄性AA肉鸡睾丸形态结构的影响,并对其内在机理进行探讨。将48只刚出壳的AA肉鸡分为4个处理组,试验组为红光组（660 nm）、绿光组（560 nm）和蓝光组（480 nm）,对照组为白光组（400-760 nm）,每组12只,自由采食。光照强度为15 lx,光照制度23 h∶1 h（L：D）。49日龄利用放射免疫法检测血清中甲状腺激素和睾酮的含量,并测量体重、睾丸重、睾丸体积、曲精细管面积和生精细胞百分数。结果表明,蓝、绿光对睾丸的影响较显著,蓝、绿光组的体重、睾丸重、睾丸体积、曲精细管面积和生精细胞百分数显著高于红、白光组7.22%-32.37%（P〈0.05）,且蓝光组T3、T4和睾酮水平比其他光组高14.36%-26.20%。结果提示蓝光比其他单色光更能促进甲状腺激素和睾酮的分泌,进而影响肉鸡睾丸的形态结构。     

Secretion of luteinizing hormone into pituitary venous effluent of the follicular and luteal phase mare: novel acceleration of episodic release during constant infusion of gonadotropin-releasing hormone

We tested the hypothesis that continuous infusion of native GnRH into mares during the estrous cycle, at a dose of 100 μg/h, would elevate circulating concentrations of LH without disrupting the endogenous, episodic pattern of LH release. Ten cyclic mares were assigned to one of two groups (n = 5/group): (1) Control (saline) and (2) GnRH in saline (100 μg/h). On experimental day 0 (3 to 6 d after ovulation), osmotic pumps containing saline or GnRH were placed subcutaneously and connected to a jugular infusion catheter. Blood samples were collected from jugular catheters daily and at 5-min intervals from catheters placed in the intercavernous sinus (ICS) for 8 h on experimental day 4 (luteal phase; 7 to 10 d after ovulation), followed by an additional 6-h intensive sampling period 36 h after PGF(2α)-induced luteal regression (experimental day 6; follicular phase). Treatment with GnRH increased (P < 0.001) concentrations of LH by 3- to 4-fold in the peripheral circulation and 4- to 5-fold in the ICS. Continuous GnRH treatment accelerated (P < 0.01) the frequency of LH release and decreased the interepisodic interval during both luteal and follicular phases. Treatment with GnRH during the luteal phase eliminated the low-frequency, long-duration pattern of episodic LH release and converted it to a high-frequency, short-duration pattern reminiscent of the follicular phase. These observations appear to be unique to the horse. Further studies that exploit this experimental model are likely to reveal novel mechanisms regulating the control of gonadotrope function in this species.     

Effects of GnRH treatment on initiation of pulses of LH,LH release,and subsequent concentrations of progesterone

Progesterone is essential for establishment and maintenance of pregnancy. One proposed method to increase progesterone is administering GnRH at insemination. However, this method has resulted in conflicting results. Therefore, 2 experiments were conducted to evaluate how administering GnRH at insemination affected pulses of luteinizing hormone (LH) and subsequent progesterone. In Experiment 1, cows were allotted to 2 treatments: (1) GnRH (100 μg) given approximately 12 h after initiation of estrus (n = 5); and (2) Control (n = 5). Blood samples were collected at 15-min intervals for 6 h at 12 (blood sampling period 1), 26 (blood sampling period 2), 40 (blood sampling period 3), 54 (blood sampling period 4), and 68 (blood sampling period 5) h after onset of estrus. Daily blood samples were collected for 17 d. In Experiment 2, cows were allotted into 2 treatments: GnRH administered 10 to 11 h (n = 10) or 14 to 15 h (n = 10) after onset of estrus. Daily blood samples were collected for 17 d. Cows treated with GnRH tended (P ≤ 0.075) to have greater LH release during blood sampling period 1, tended (P = 0.095) to have fewer pulses during blood sampling period 2, tended (P = 0.067) to have greater concentrations of progesterone, and had an earlier (P = 0.05) increase in progesterone than control cows. Cows treated with GnRH 10 to 11 h after onset of estrus had greater (P = 0.01) progesterone and an earlier (P = 0.04) increase in progesterone than cows treated 14 to 15 h. In conclusion, timing of GnRH treatment following onset of estrus influenced pulses of LH and subsequent progesterone.     

Oestradiol stimulates the release of AVP and GnRH from the ewe hypothalamus in vitro.

Oestradiol (E(2)) sensitizes the stress and reproductive axes in vivo. Our current aim is to investigate whether E(2) directly influences hypothalamic AVP and GnRH release in vitro. Within 10 min of ewe killing, saggital midline hypothalamic slices (from the anterior preoptic area to mediobasal hypothalamus, 2 mm thick, two per sheep) were dissected, placed in oxygenated MEM-alpha at 4 degrees C and within next 2 h were singly perifused at 37 degrees C with oxygenated MEM-alpha (pH 7.4; flow rate 150 microl/min) alone (vehicle; n = 15), with low (6 pg/ml; n = 14) or high E(2) (24 pg/ml; n = 13). After 5 h equilibration, 10 min fractions were collected for 3 h with exposure to 100 mm KCl for 10 min within the last hour. Concentrations of AVP and GnRH were measured by RIA. Baselines for AVP and GnRH were 7.0 +/- 1.1 and 17.4 +/- 0.8 pg/ml respectively. Basal values with low E(2) were similar to vehicle for AVP (7.5 +/- 1.2 pg/ml) and GnRH (17.5 +/- 1.1 pg/ml). However, high E(2) increased basal AVP (11.7 +/- 1.4 pg/ml; p < 0.05) and GnRH (23.7 +/- 1.4 pg/ml; p < 0.05). After KCl, AVP and GnRH respectively, increased (p < 0.05) to 25.6 +/- 7.5 and 38.2 +/- 5.6 (vehicle), 26.3 +/- 7.5 and 23.6 +/- 2.1 (low E(2)) and 24.1 +/- 5.4 and 41.3 +/- 6.6 pg/ml (high E(2)). After KCl, maximum values of AVP occurred at 20 and GnRH at 30 min. In conclusion, high E(2) concentration augments AVP and GnRH release by direct action on the ewe hypothalamus.     

The effect of an extended artificial photoperiod and gonadotrophin-releasing hormone infusions in inducing fertile oestrus in anoestrous mares

The occurrence of fertile oestrus early in the breeding season is of paramount importance to the Thoroughbred industry to facilitate early conception. This paper compares 2 techniques for inducing fertile oestrus in anoestrous mares using either an extended photoperiod alone or together with gonadotrophin-releasing hormone (GnRH) infusions. Eleven mares were placed under conditions of 16 h light and 8 h darkness and 5 of these were implanted with osmotic minipumps delivering approximately 100 ng GnRH/kg/h for 28 days (treated mares). The treated mares ovulated 27.7 days earlier than and conceived 32 days earlier than the 6 mares not given GnRH. GnRH-induced ovulations were followed by a competent luteal phase. The combination of GnRH pumps implanted 2 weeks before commencement of service together with extended photoperiod from July 1 has promise in assisting the stud breeder to improve reproductive efficiency on commercial stud farms.     

Expression of fibroblast growth factor 1 (FGF1) and FGF7 in mature follicles during the periovulatory period after GnRH in the cow

The aim of this study was to evaluate the expression pattern of mRNA for fibroblast growth factor 1 (FGF1), FGF7, and their receptor variants (FGFR2IIIb) in time-defined follicle classes before LH surge, between LH surge and ovulation, and in the early corpus luteum (CL) in the cow. The ovaries were collected by transvaginal ovariectomy (n=5 cows/group), and the follicles (n=5, one follicle/cow) were classified into the following groups: before GnRH administration (before LH surge); 3-5 h after GnRH (during LH surge); 10 h after GnRH; 20 h after GnRH; 25 h after GnRH (periovulation), and early CL (Days 2-3). The mRNA expression was analyzed by quantitative real-time PCR (RotorGene 3000). The mRNA expression of FGF1 showed no significant differences in the follicle groups examined, but increased significantly at the early CL phase. A transient increase in FGF7 mRNA expression was observed 3-5 h after GnRH and again in the early CL phase. In contrast, the expression of FGFR2IIIb was constant throughout the period from the final growth of the follicle to early CL formation. The results of this study suggest that FGF1 and FGF7 may be involved differently in the process of follicle maturation and CL formation, which is strongly dependent on angiogenesis.     

Influence of the duration of photoperiod on growth,testicular characteristics and endocrine function of boars

Crossbred boars were used to evaluate the influence of exposure to 8 or 16 hr of light daily from 75 to 175 days of age on growth rate, testicular characteristics and endocrine function. At 160 days of age, concentrations of testosterone in serum (P<.10), the areas under plotted 12 hr testosterone profiles (P<.10) and the number (P<.05) and magnitude (P<.10) of testosterone secretory spikes were increased in boars exposed to 16 hr of light compared to boars in 8 hr light, but concentrations of LH in serum were similar in boars exposed to both treatments. Treatment with GnRH resulted in similar concentrations of LH in serum for both groups of boars. Testosterone in serum after GnRH-mediated LH release was greater at .5 (P<.05) and 1.0 (P<.10) hr following GnRH in boars exposed to 16 hr of light compared to boars at 8 hr, but concentrations of testosterone were similar for both treatments from 1.5 to 4.0 hr after GnRH. Growth rate and testicular and epididymal weights and sperm reserves at 175 days of age were not significantly altered by duration of photoperiod. Boars exposed to 8 hr of light had more hair per unit area than boars exposed to 16 hr of light. We conclude that exposure of prepubertal boars to longer daily photoperiods results in increased concentrations of testosterone in serum at 160 days of age.     

Effects of induction of ovulation with GnRH or HCG on follicular and luteal blood flow in Holstein-Friesian heifers

The objective of this study was to compare the effects of gonadotropin-releasing hormone (GnRH) and human chorionic gonadotropin (hCG) on follicular blood flow (FBF) during the pre-ovulatory period and on luteal blood flow (LBF) during dioestrus in Holstein-Friesian heifers. Twelve animals were randomly divided into two groups and treated with either intramuscular injection of 100 μg GnRH or intravenous (IV) injection of 5000 IU hCG on Day 0 (oestrus, 48 h after administration of PGF(2α) ) to induce ovulation. Follicular size (FS), FBF and time of ovulation were recorded with colour Doppler sonography at 0, 1, 3, 6, 12 and 24 h after GnRH and hCG treatment. Luteal size (LS) and LBF were investigated on Day 9 and 12 after ovulation. Plasma samples were taken to determine total oestrogens (E(tot) ) and progesterone (P(4) ) after each examination. Ovulation occurred between 24 and 48 h after treatment in all animals. No difference (p > 0.05) was observed in FS between the two treatment groups. Follicular blood flow was higher in the hCG group than that was in GnRH group at 1 h after treatment (p < 0.01). Total oestrogens were also higher (p < 0.01) in the hCG group than GnRH group; however, this difference was only obvious at 12 h after treatment. No difference (p > 0.05) was observed in LS, LBF or P(4) levels on Day 9 and 12 between treatment groups. In conclusion, the results suggest that induction of ovulation with hCG and GnRH has a temporary effect on FBF and oestrogen levels while no effect on the size of corpora lutea, LBF and P(4) levels was observed.