侧脑室注射牛胰多肽对家兔糖耐量和血清胰岛素浓度的影响

在家兔侧脑室内微量注射牛胰多肽能增加其糖耐量及血清胰岛素浓度。这种作用与牛胰多肽注射剂量有明显依从关系,并被预先皮下注射阿托品所部分阻断。结果提示,中枢给予牛胰多肽可能部分通过迷走神经途径增加血清胰岛素的释放而增加糖耐量。     

兔侧脑室注射胰高血糖素对血清总胆固醇和甘油三酯浓度的影响

我们最近曾报道,向兔侧脑室内注射胰高血糖素有明显降低血浆自由脂肪酸的作用。本工作又进一步观察了它对空腹血清总胆固醇和甘油三酯浓度的影响。结果发现:(1)对血清总胆固醇浓度无明显作用;(2)能引起血清甘油三酯浓度的下降,且与剂量有依赖关系,在注射后的 75min降低最显著,以后则逐渐恢复;(3)皮下注射阿托品(0.2mg/kg)或静脉注射心得安(5mg/kg)均不能消除侧脑室注射胰高血糖素降低血清甘油三酯的作用;(4)静脉注射酚妥拉明(5mg/kg)能阻断侧脑室注射胰高血糖素的降低血清甘油三酯的作用。这些结果表明脑内的胰高血糖素对血清甘油三酯的影响可能是通过肾上腺素α-受体起作用的。     

外源性及内源性生长抑素对链佐霉素糖尿病小鼠血清胰岛素的作用

已经证明用链佐霉素(简称 STZ)可诱发小鼠产生低胰岛素糖尿病,本工作用外源性注射生长抑素(简称 SS)和用半胱胺特异性耗竭内源性 SS 的方法,观察 SS 对 STZ 糖尿病小鼠血清胰岛素的影响。在注射 STZ(60mg/kg,ip)前10min 分别皮下注射 1μg/kg,5μg/kg,10μg/kg 的 SS 可预防 STZ 诱发的血清低胰岛素作用,并呈剂量-效应关系。注射半胱胺(300mg/kg,SC)24h 后再连续5d 皮下注射半量半胱胺维持,胰腺组织匀浆中的 SS 含量经放免测定鉴定已基本被耗竭。在实验的第7,9,11,16d 胰腺 SS 含量仍然维持在比对照组为低的水平,给这种小鼠注射 STZ,其血清胰岛素降低程度比仅接受 STZ 小鼠的大,此外,给耗竭胰腺内 SS的小鼠注射不足以引起高血糖的 STZ 也引起了血糖大大升高。以上结果表明,不仅外源性 SS有预防链佐霉素诱发的小鼠低血清胰岛素发生的作用,胰腺组织中的内源性 SS 也可能是一个对胰岛 B 细胞起保护作用的因素。     

兔侧脑室注射八肽胆囊收缩素抗血清对血浆自由脂肪酸浓度的影响

本工作根据抗原抗体间具有高度特异性的中和作用的原理,将微量 CCK-8抗血清注射入制备有埋藏套管的慢性实验兔的侧脑室内,观察在中和脑内外源性或内源性的 CCK-8后,血浆 FFA 浓度的变化,结果如下:1.侧脑室内注射正常兔血清,对血浆 FFA 浓度无明显影响;在注射 CCK-8同时注射兔正常血清,也不影响 CCK-8降低血浆 FFA 浓度的作用。2.侧脑室内注射 CCK-8抗血清能有效地阻断外源性脑室注射 CCK-8降低血浆 FFA 的作用,此阻断作用随 CCK-8抗血清剂量的增加而增强。3.侧脑室内单独注射 CCK-8抗血清,血浆 FFA 浓度明显升高,这一作用可能是由于中和了脑内内源性 CCK-8的作用所致。以上结果表明,CCK-8脑室注射引起的血浆 FFA 降低的作用具有一定的特异性;而在正常生理情况下,脑内释放的内源性 CCK-8可能参与血浆 FFA 代谢的调节。     

兔呼出气氚水浓度曲线测定及其意义

本文报告以自制玻璃冷却小壶为主的冷凝装置在-21℃下连续收集测定呼出气微量氚水的方法。由腔静脉“团块”注入氚水,每5秒呼出气为一样本,测定1min 正常兔呼出气氚水浓度曲线。18只兔33次实验的平均曲线中,第一个样本氚水浓度1.16±0.31(SE),继而迅速上升,25—40s 达最高值(10.43—10.53),以后缓慢下降,平均浓度7.93±0.47(SE)。阻断支气管动脉时呼出气氚水浓度为未阻断时的65%±15%(SD);主动脉弓注入氚水的模拟再循环呼出气氚水浓度为对照值的4.31%;呼出气氚水平均浓度与通气指标、体温、环境湿度不相关。结果说明呼出气氚水浓度曲线是氚水经肺首次循环时透过血-气屏障的转移所产生。呼出气氚水曲线高峰滞后于血液稀释曲线高峰20—35(?)s,可能反映氚水在肺内转移中有滞留现象.呼出气氚水浓度曲线可作为研究肺水转移和诊断肺水肿的新方法,我们首次观察的现象和数据亦可作进一步研究的参考     

DISTRIBUTION AND MULTIPLICATION OF COLONY FORMING UNITS FROM BONE MARROW AND SPLEEN AFTER INJECTION IN IRRADIATED MICE

The distribution and proliferation of CFUs from bone marrow and spleen cell suspensions were followed after injection in lethally irradiated isogeneic mice. It was found that a larger proportion of the injected bone marrow CFUs than of the spleen derived CFUs could be recovered from the recipient's spleen and femur. This consistently higher recovery points to the conclusion that a larger fraction of bone marrow-derived CFUs than of spleen-derived CFUs is capable of producing daughter CFUs, most likely due to a commitment to early differentiation of many spleen CFUs.     

青霉素和苯巴比妥钠对小鼠全脑切片积聚~3H-GABA的影响

本文应用同位素示踪、脑片离体培育和侧脑室注射的方法,在体外和体内研究了惊厥剂青霉素和抗惊厥剂苯巴比妥钠对小白鼠全脑切片积聚~3H-GABA的影响。结果表明:(1)在含6.70—13.40×10~(-4)mol/L的苄青霉素钾(PG)100μl或19.60—39.20×10~(-4)mol/L的苯巴比妥钠(PhB)50μl的培育液(2ml)中,小鼠全脑切片对~3H-GABA的积聚作用明显降低(P<0.05)。6.70×10~(-4)mol/L的PG100μl和39.20×10~(-4)mol/L的PhB50μl同时注入培育液(2ml)时,脑片对~3H-GABA的积聚比PG单独试验时稍有升高。(2 )小鼠侧脑室注射20μl的 3.35×10~(-2)mol/L的PG可引起强烈的惊厥,脑片上的~3H-GABA积聚减少(P>0.05);脑室内注射10μl的3.88×10~(-2)mol/L的PhB能抗惊厥,也使~3H-GABA在脑片上的积聚减少(P>0.05);脑室内同时注射PG和PhB,使~3H-GABA在脑片上的积聚恢复正常。以上结果提示:青霉素可通过竞争突触后膜和神经末梢上的GABA受体,阻断GA-BA的突触后抑制效应及抑制GABA释放,显示惊厥作用;苯巴比妥钠也可和突触后膜上的GABA受体结合,产生GABA样作用或激活GABA受体,起抗惊厥作用。     

CIRCADIAN VARIATION OF SERUM LEPTIN IN HEALTHY AND DIABETIC MEN

Leptin, from the Greek leptos, meaning thin (in reference to its ability to reduce body fat stores), is a hormone secreted primarily by adipocytes. At one time, leptin was portrayed as a potential means of combating obesity. Recently, leptin has been identified as a potent inhibitor of bone formation, acting through the central nervous system. Since numerous studies clearly show that bone remodeling is circadian rhythmic with peak activity during sleep, it is of interest to explore circadian variability in serum leptin. Accordingly, circadian characteristics of serum leptin were examined in 7 clinically healthy men and 4 obese men with type II diabetes. Blood samples were collected for 24h at 3h intervals beginning at 19:00. The dark (sleep) phase of the light-dark cycle extended from 22:30 to 06:30, with brief awakening for sampling at 01:00 and 04:00. Subjects consumed general hospital meals (2400 calories) at 16:30, 07:30, and 13:30. Serum leptin levels were determined by a R&D Systems enzyme immunoassay technique. Data were analyzed by linear least-squares estimation using the population multiple components method. A statistically significant (P <. 018) circadian rhythm modeled by a single 24h cosine curve characterized the data of each group. The 24h mean leptin level was statistically greater (P <. 001) in the obese diabetic men than in the healthy men (9.47 ± 0.66 ng/mL vs. 24.07 ± 1.71 ng/mL, respectively). Higher leptin levels occurred between midnight and roughly 02:30, and lowest leptin levels occurred between noon and the early afternoon. The phasing of this rhythm is similar to the circadian rhythm in bone remodeling previously described. Our results suggest the findings from a single morning blood sampling for leptin may be misleading since it may underestimate the mean 24h and peak concentrations of the hormone. (Chronobiology International, 18(2), 273–283, 2001)     

互花米草幼苗在不同浓度NaCl溶液中的生长和溶质的积累

互花米草在NaCl营养液中能够大量积累Na~+和Cl~-,并对K~+、可溶性糖和游离脯氨酸的积累也有一定的促进作用,同时抑制了Ca~(2+)、Mg~(2+)和Pi的吸收。幼苗积累Na~+和Cl~-作为主要渗透剂。Na~+/K~+比值随着培养基NaCl浓度增大而提高。根部无机离子的总量明显高于地上部。NaCl明显降低幼苗地上部的渗透势,其变化随培养基渗透势的下降而降低。在NaCl营养液中培养的幼苗鲜重和含水置下降,但对于重影响不大,鲜重/干重比值随培养基NaCl浓度增大而降低。     

激光照射胚泡对家兔和小鼠的抗早孕研究

本文在家兔、小鼠上探索了激光的抗旱孕效应,观察到血卟啉衍生物(HPD)和激光的光化效应能使早期胚泡完全坏死和吸收,无流血和晚期流产现象,通过PNQ_3荧光分光光度计测定HPD在胚胎组织中的荧光谱,证实HPD对胚胎组织有亲和力,其对滋养叶细胞比对宫壁组织的亲和力大4倍,借以解释激光光化效应抗早孕的可能机理。     

尿激酶及其抑制物对未成年小鼠排卵的影响

利用未成年小鼠超数排卵方法,研究了纤溶酶原激活因子——尿激酶和它的抑制物——6氨基己酸对排卵的作用。实验结果表明:18日龄小鼠在注射PMSG和hCG条件下,增注尿激酶800U,排卵动物数及平均排卵数与对照组比较有显著性差异。如果仅用PMSG和尿激酶,不能引起动物排卵。21日龄小鼠在注射PMSG后再注射不同剂量hCG情况下增注尿激酶,平均排卵数均比相应对照组有显著性差异,但hCG注射量为l.25IU组,增注尿激酶后,实验组与对照组平均排卵数无显著性差异。用尿激酶抑制剂6氨基己酸可以有效抑制超数排卵的效果。实验结果提示,尿激酶只有在hCG存在条件下对小鼠排卵有促进作用,而尿激酶本身不具有诱发排卵的作用。     

酪氨酸对男子血清促性腺激素和睾酮浓度的影响

给成年男子(n=5)口服酪氨酸300mg/日,共6天,第四天肌注 LRH-A 150μg/人,用RIA 法测定其血清 LH、FSH 和睾酮浓度。与对照组(n=5)相比,酪氨酸对 LH 和 FSH 的基础水平和 LRH-A 诱发的 LH 峰和 FSH 峰均无明显影响。睾酮的基础水平稍有升高,而酪氨酸对 LRH-A 引起的睾酮水平升高有明显的抑制作用。结果提示,酪氨酸可不通过垂体而直接作用于睾丸以影响睾酮的分泌。     

尾核内注入GABA、Picrotoxin对家兔食物性运动条件反射的影响

于家兔尾核头部分别注入γ-氨基丁酸(GABA)3mg/5μl、GABA 转氨酶的抑制剂氨氧乙酸(AOAA)10μg/5μl 及 GABA 受体阻断剂印防已毒素(Picrotoxin)0.5μg/5μl 后,可暂时抑制食物性条件反射的出现,但一般运动、摄食等机能无明显障碍。作为对照,在尾核头部注入生理盐水或士的宁不影响条件反射的出现,注射 Picrotoxin 等于内囊区及海马也不影响条件反射活动。实验结果表明,尾核头部 GABA 能突触传递与实现条件反射活动有关。     

SYNTHESIS OF RNA IN NEURONS OF THE HYPOGLOSSAL NERVE NUCLEUS, AFTER SECTION OF THE AXON, IN MICE

Synthesis of RNA in neurons of the hypoglossal nerve nucleus after axonal section was studied by means of [5-³H]uridine administration and radioautographic counting techniques in mice. The results of the experiments were evaluated by counts of silver grains over the nucleoplasm and cytoplasm of the neurons. RNA synthesis was greater in neurons after axonal section, and this increase was evident from 12 hr after the operation. The greatest increases in the operated side were observed in the 1st, 2nd and 3rd days after operation. In the 7th and 14th days RNA synthesis was still greater in the hypoglossal nucleus of the sectioned nerve but the difference in the control nucleus was not so striking. In the 30th day synthesis of RNA in left and right hypoglossal nuclei was comparable.     

THE PRESENCE OF A CSF ENHANCING ACTIVITY IN THE SERUM OF ENDOTOXIN-TREATED MICE

Serum taken from mice a few hours after injection of endotoxin is a potent source of a stimulator of in vitro myelopoiesis. By means of dose-response studies, the biological activity of this material was compared to that of a colony stimulating factor (CSF) from pregnant mouse uteri. Postendotoxin serum appears to contain two different activities: a stimulating activity which may be identical to CSF and an activity which augments the action of CSF. The separate nature of the two activities is demonstrated by differences in the rate at which they are diluted out and by differences in the time at which they are maximally present after endotoxin administration. It is therefore concluded that the colony-stimulating properties of postendotoxin serum are not due solely to CSF present in the serum.