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排序方式: 共有268条查询结果,搜索用时 15 毫秒
1.
本工作通过测定大鼠血清、胰腺灌流液以及肤腺组织中胰岛素含量,观察生长抑素(SS)对链佐霉素(STZ)诱发的实验性糖尿病的作用。结果如下:皮下注射生理盐水后10min,再向腹腔注射链佐霉素(35mg/kg),24h 后大鼠血清胰岛素浓度明显降低。胰腺组织匀浆中的胰岛素含量也明显减少。如若在注射链佐霉素前10min 皮下注射生长抑素,则可有效地防止上述两项指标的改变,(NS STZ)和(SS STZ)两组之间具有显著差异。单独注射生长抑素,24h 后血清胰岛素及胰腺组织中胰岛素含量与正常对照无明显差异。用分离的大鼠胰腺作体外灌流,观察到:NS STZ 组大鼠灌流胰腺对19.7mmol/L 的高浓度葡萄糖刺激无胰岛素释放反应,而 SS STZ 组大鼠的胰腺对高浓度葡萄糖有反应性,刺激后出现胰岛素分泌峰。上述结果表明,SS(30μg/kg)预防性注射可以防止 STZ 引起的胰岛 B 细胞分泌功能的障碍。 相似文献
2.
我们以前的工作指出,生长抑素可以预防链佐霉素对大鼠胰岛B细胞的损伤。本工作测定给药前后大鼠血清和组织中Zn、Cu含量,以进一步观察链佐霉素破坏大鼠胰岛B细胞后生长抑素预防效应的可能机制。结果为:链佐霉素(STZ)(35mg/kg,ip)注射后24h的大鼠,血清Zn浓度下降,Cu浓度升高,Zn/Cu比值倒置;用生长抑素作预防性注射后,血清Zn浓度与正常对照水平相同,Cu浓度虽稍有升高,但Zn/Cu比值正常。保护组的血清Zn与损伤组比较,差异极为显著。两组的Zn/Cu比值同样也具有显著差异。在给药后72h,血清Zn/Cu比值在各组之间仍呈上述关系,但差异减小。在大鼠胰腺,注射链佐霉素后胰腺组织Zn浓度未见改变,但生长抑素作预防性注射可使组织锌含量增加。上述结果提示,在生长抑素对胰岛B细胞的保护机制中可能有Zn和Cu的参与。预防性注射生长抑素所引起的高Zn状态可能有利于机体细胞含Zn酶类的活性,增强已损伤细胞的修复。 相似文献
3.
The current study was designed to determine if insulin, glucagon and somatostatin-containing cells are present in the pancreas of adult Xenopus laevis. Localization methods utilized included cytochemical aldehyde fuchsin (AF) staining as well as the immunochemical peroxidase antiperoxidase (PAP) procedure for light microscopy. The results show numerous large clusters of AF-positive cells within a network of highly vascularized acinar tissue. PAP immunochemical localization with insulin antibody on adjacent sections demonstrates positive immunoreactivity to AF-positive cell groups and also the presence of immunoreactive insulin (IRI). Cells exhibiting this immunoreactivity are located in the central region of the islet-like structures. Serial sections not only show PAP immunoreactivity for IRI, but also for immunoreactive glucagon (IRG) and immunoreactive somatostatin (IRS) in the same islet-like structure. IRG and IRS-containing cells are situated around the periphery of the islet-like structures, surrounding the central core of IRI-containing cells. Antibody specificity was confirmed by homologous and heterologous antigen immuno-absorbance assays, as well as incubation of adjacent sections in preimmune sera. Based on this data we conclude that: the distribution of cells of the endocrine pancreas of metamorphosed Xenopus laevis is similar to that of many mammals and certain urodeles. Given the apparent specificity of the antigen-antibody reactions, it appears that Xenopus insulin, glucagon and somatostatin are structurally conserved. 相似文献
4.
Pancreatic hypertrophy and hyperplasia following chronic joint (CA + SE), or separate, caerulein (CA: 1 microgram . kg-1) and secretin (SE: 75 micrograms . kg-1) administration were studied in parallel with pancreatic somatostatin (SRIF) contents following 2, 4, 7 and 10 days of treatment. Parameters indicative of pancreatic growth (tissue weight, DNA and protein contents, cellular protein concentrations) increased significantly after 2 days of CA or CA + SE and reached a plateau between days 4 and 10. SE merely induced a mild hypertrophy after 4 days. Endogenous pancreatic SRIF contents varied upon treatment, differently so with each peptide regimen. Indeed, CA and CA + SE treatments decreased total SRIF contents after 2 days with no effect thereafter. SE also decreased the latter after 2 days while significant increases were observed after 7 and 10 days. The inverse relationship seemingly existing between SRIF contents and the amplitude of hormonally-induced pancreatic growth supports the hypothesis that endogenous pancreatic SRIF, operating as an 'antigrowth' factor, may participate in the exogenous CA, SE and CA + SE stimulated pancreatic growth phenomena. 相似文献
5.
J Takemura Y Seino S Nishi H Ishida M Sakita T Taminato T Chiba H Imura 《Regulatory peptides》1983,6(4):379-384
The effects of PGE2 and PGD2 on gastric somatostatin and gastrin releases were investigated using the isolated perfused rat stomach. In the presence of 5.5 mM glucose, the infusion of PGE2 elicited a significant augmentation in somatostatin release, but suppressed gastrin secretion from the perfusate. On the other hand, PGD2 did not affect somatostatin release, although the gastrin secretion decreased significantly, the same as after PGE2 infusion. These results suggest that PGE2 and PGD2 may be important in the regulation of gastric endocrine function, but that PGD2 does not affect gastric somatostatin secretion. 相似文献
6.
S A Nicholson T E Adrian A J Bacarese-Hamilton B Gillham M T Jones S R Bloom 《Regulatory peptides》1983,7(4):385-397
The tissue content of up to eight neuropeptides, viz bombesin (BOM), cholecystokinin (CCK-8), neurotensin (NT), neuropeptide Y (NPY), peptide histidine isoleucine amide (PHI), somatostatin (SRIF), substance P (SP) and vasoactive intestinal polypeptide (VIP), in rat hypothalami removed at various times of the day, was measured using specific radioimmunoassays. There was significant variation in the content of BOM, CCK-8, NT, PHI, SP and VIP across a 24-h period. The levels of BOM, CCK-8 and NT were lowest around the onset of darkness (1900 h) and rose throughout the night to reach a peak around the time of lights on. Hypothalamic content of all eight peptides fell between 0700 h and 1300 h by an average of 45 +/- 4%. Basal release of these peptides, as well as that in the presence of 48 mM potassium (K+), was measured from hypothalami removed between 0700 and 1900 h and incubated in vitro in a CSF-like medium. Basal secretion of NT significantly increased, whilst that of CCK-8 significantly decreased over the same period. There was no significant change in the basal release of the other neuropeptides. The release in the presence of 48 mM K+ of SP decreased significantly during the day, whilst that of VIP significantly increased. There was also a significant change in the stimulated release of BOM, levels falling during the morning and rising again at 1900 h. 48 mM K+ caused a significant increase in the release of SRIF and SP at all times tested. Whilst 48 mM K+ induced a significantly higher release of CCK-8 and NT in the morning, this stimulus was ineffective in the evening. The contrary was true in the case of BOM, NPY and VIP, where a significant stimulation was induced only at 1900 h. The possible implications of these findings are discussed. 相似文献
7.
Gary W. Arendash William J. Millard Ralph Dawson Jr. Adrian J. Dunn Edwin M. Meyer 《Neurochemical research》1989,14(11):1113-1118
Young adult rats received either unilateral or bilateral ibotenic acid infusions in their nucleus basalis, destroying most of the cholinesterase-staining neurons in that region. Cerebral cortex levels of choline acetyltransferase, somatostatin, neuropeptide Y, and monoamines were then assayed 2.5 and 10 months after bilateral lesions, or, 2.5, 10, and 14 months after unilateral lesions. Entorhinal and cerebral cortex levels of several amino acid transmitters were also measured. As expected, choline acetyltransferase activity was decreased in the frontal cortex ipsilateral to the ibotenic acid infusion in unilaterally or bilaterally lesioned animals. Parietal cortex concentrations of somatostatin and neuropeptide Y were altered by lesioning in a complicated, time-dependent manner. Thus, while unilateral lesions transiently decreased or had no effect on these neuropeptide levels, bilateral lesions elevated the level of each neuropeptide by over 100% at 10 months. Other cortical transmitter systems investigated appeared to be less affected by nucleus basalis-lesions. Unilateral lesions had no effect on prefrontal cortex norepinephrine, serotonin, or dopamine content at 14 months post-lesioning. These different neurochemical effects of unilateral and bilateral nucleus basalis lesions may be important for developing a model for the trans-synaptic effects of cortical cholinergic deafferentation. 相似文献
8.
J. A. Chowen L. M. García-Segura S. González-Parra J. Argente 《Cellular and molecular neurobiology》1996,16(3):297-310
Summary 1. The secretory pattern of growth hormone (GH) is sexually dimorphic in the adult rat. However, this difference between the sexes does not become apparent until after the onset of puberty, suggesting that pubertal sex steroids play an important role in the manifestation of this phenomenon.2. We have addressed the question as to whether there exists a sexual dimorphism in the hypothalamic neuropeptides that regulate GH release from the anterior pituitary,i.e., somatostatin (SS) and growth hormone-releasing hormone (GHRH). In addition, we have investigated whether the developmental changes in the GH secretory pattern are correlated with changes in these neuropeptides. The effect of testosterone treatment on SS and GHRH neurons during both the neonatal period and adulthood have also been studied.3. We have found that the synthetic capacity, as reflected in relative messenger RNA (mRNA) levels, of both SS and GHRH neurons changes throughout development in both male and female rats. These mRNA levels are sexually dimorphic at certain times during maturation and can be modulated by changes in testosterone levels, suggesting that sex steroid modulation of these two neuropeptide systems could at least partially account for the sexual dimorphism seen in the adult GH secretory pattern.4. The neonatal steroid environment has also been suggested to be involved in the generation of the final adult GH secretory pattern, although the mechanisms underlying this effect are even less well understood. In support of the hypothesis that the neonatal steroid environment plays an important role in organizing the GH axis, we have found that the number of GHRH neurons in the adult brain, as well as their sensitivity to adult steroids, is modulated by neotatal testosterone treatment. The number of SS neurons in the periventricular and paraventricular nuclei were not modulated by neonatal steroids; however, the synthetic capacity of these neurons does appear to be influenced by the neonatal steroid environment.5. These studies suggest that both the neonatal and adult sex steroid environments influence the adult GH secretory pattern by modulating GHRH and SS neurons. 相似文献
9.
生长抑素(somatostatin, SST)作为一种抑制性多肽激素,在多种生物过程中发挥重要的功能。生长抑素受体2 (somatostatin receptor 2, SSTR2)作为生长抑素表达最广泛的受体在多种组织中表达,但其表达的具体细胞类型尚不清楚。本研究在小鼠不同发育阶段的多种组织中鉴定了SSTR2蛋白表达的细胞类型。通过多色免疫荧光在小鼠胚胎期15.5 d、出生后1 d、7 d、15 d、3个月和6个月的脑、骨、肺、肠道、皮肤、胃、脾和肾等组织中检测了Sstr2基因的表达。结果发现Sstr2在不同发育阶段的多种组织的特定细胞类型中表达,包括脑神经元和星形胶质细胞,骨的间充质基质细胞、造血细胞和B细胞,肺的巨噬细胞、Ⅱ型肺泡上皮细胞和气道纤毛细胞,肠道的上皮细胞和神经元,皮肤的毛囊细胞,胃体的上皮细胞,脾的造血干细胞、造血祖细胞和神经纤维,肾的肾小管上皮细胞等。本研究确定了小鼠多组织不同发育阶段Sstr2表达的细胞类型,为生长抑素与生长抑素受体2的生理功能研究提供了新的线索。 相似文献
10.
生长抑素在糖尿病大鼠胰腺外分泌功能降低中的作用 总被引:1,自引:0,他引:1
本实验观察到,用链佐霉素造成大鼠糖尿病模型,其胰腺组织中生长抑素含量明显升高。大鼠皮下注射生长抑素(100μg·kg~(-1)·d~(-1))5d,其胰腺组织中淀粉酶的含量明显降低。体外胰腺灌流也表明,生长抑素能抑制CCK—8刺激引起的胰腺淀粉酶释放。以上结果提示,糖尿病时胰腺组织中生长抑素含量的增加可能在胰腺外分泌功能降低中有一定的作用。 相似文献