首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到10条相似文献,搜索用时 106 毫秒
1.
Cell-mediated and humoral immune responses to heterologous insulins in mice are controlled by H-2 linked, dominant, immune response (Ir) genes. For example, mice bearing the H-2d haplotype develop T cell proliferative responses and produce antibody after injection with porcine insulin, whereas mice bearing other H-2 haplotypes do not. Data presented in this communication demonstrate that homozygous and heterozygous H-2d mice produce insulin-binding antibodies when immunized with porcine insulin or proinsulin. Some (H-2b,k,s) insulin-nonresponder mice produce insulin-binding antibodies after injection of proinsulin, whereas other insulin-nonresponder strains (H-2q) do not. All strains, except homozygous H-2q mice, produce antibodies specific for proinsulin, suggesting that the response to porcine proinsulin is also controlled by H-2-linked Ir genes. More importantly, F1 hybrids between insulin-nonresponder C57BL/10 (H-2b) and DBA/1 (H-2q) produce no insulin-binding antibodies when injected with proinsulin, despite the fact that proinsulin-binding antibodies are produced by these mice.  相似文献   

2.
Expression of the diabetes ( db/db) genotype mutation in female C57BL/KsJ mice induces a complex diabetes-obesity syndrome (DOS) responsible for reproductive tract involution promoted by hypercytolipidemia (HCL). Current studies define the complex and influences of the endometabolic variables that promote reproductive tract involution at the time of initial db/db mutation expression onset in female C57BL/KsJ mice. Littermate-paired, normal ( +/?) and db/db groups were isolated between 2 - 4 weeks of age and tissue samples analyzed for utero-ovarian alterations induced by the systemic, tissue, cellular and structural consequences of mutation expression. Significantly elevated body weights, blood glucose concentrations and serum insulin levels contrasted with atrophic utero-ovarian indices in db/db mutants compared to +/? groups. The onset of the db/db-expression promoted obesity and a mild hyperglycemic-hyperinsulinemic state. Initial db/db expression was characterized by significantly increased utero-ovarian insulin binding without variation in membrane insulin receptor concentrations. However, significant elevations in tissue glucose sequestration rates, norepinephrine (NE) concentrations and triacylglyceride lipase activity in db/db groups indicated that a complex of endometabolic counter-regulatory influences promoted the metabolic shunting of excess glucose and triglyceride moieties towards hypercytolipidemic storage. The resulting DOS-promoted accumulation of utero-ovarian cytolipidemic pools compromised reproductive tract cytoarchitecture in db/db mice. The results of these studies indicate that the inability of utero-ovarian tissue compartments to exhibit metabolic adaptation to the enhanced availability, transport and cellular imbibition of extracellular glucose-lipid pools promotes the initial cellular compromise recognized to induce reproductive failure in db/db mutants.  相似文献   

3.
Monoclonal autoantibodies cytotoxic for murine islet cells have been obtained by cell fusion using spleen cells from non-immunized diabetic C57BL/KsJ (db/db) Mice. These monoclonals, of IgG2a subclass, blocked in vitro insulin secretion induced by arginine in Mouse pancreatic cells.  相似文献   

4.
Aqueous extract of Ocimum canum Sim, (Lamiaceae) is used by some Ghanaians to manage diabetes mellitus. In vivo modulation of levels of fasting blood glucose by 0. canum extract was evaluated in type-II diabetes mellitus using the C57BL/KsJ db/db genetically diabetic animal model, and its effects on glucose-stimulated insulin release in vitro were monitored using isolated rat pancreatic beta-islet cells. The results showed that fasting blood glucose levels and body weight decreased significantly (p < 0.05) in diabetic and non-diabetic C57BL/KsJ mice, which were administered aqueous extract of 0. canum. In vitro, the 0. canum extract significantly enhanced insulin release from isolated rat pancreatic beta-islet cells. Insulin release was found to be dependent on glucose concentration and increased with increasing O. canum concentration in the incubation medium up to an optimum extract concentration of 0.03 mg/ml. Release of the hormone decreased beyond this concentration of extract in the medium. Addition to the medium of Desmodium adscendens, a plant preparation used to manage inflammatory disorders, did not increase but rather inhibited insulin secretion by the pancreatic beta-islet cells. These results could explain the use of 0. canum in Ghanaian folk medicine to manage diabetes mellitus.  相似文献   

5.
The concentrations and contents of immunoreactive substance P (SP), neurokinin A (NKA), vasoactive intestinal polypeptide (VIP) and gastrin releasing peptide (GRP) were measured in acid-ethanol extracts of intestine (duodenum-jejunum-ileum) and pancreas of C57BL/KsJ diabetes-obese (db/db) mice, Aston obese-hyperglycaemic (ob/ob) mice, and their respective lean controls. The intestinal concentration of GRP and pancreatic concentrations of VIP and GRP were 36-57% lower in lean Aston mice than lean C57BL/KsJ mice, indicating the influence of genetic background in control mice. Intestinal concentrations of SP and NKA were reduced by 19-33% in the db/db and ob/ob mutants compared with their lean controls, but the intestinal contents of these peptides were normal or greater than normal due to intestinal hypertrophy of the mutant mice. The intestinal VIP concentration was not altered, but the content was increased by 87% and 25% respectively in db/db and ob/ob mice, whereas the intestinal GRP concentration was reduced by 51% in ob/ob mice. Pancreatic concentrations and contents of NKA, VIP and GRP were similar in lean and db/db C57BL/KsJ mice. However, pancreatic concentrations and contents of VIP and GRP were reduced by 51-55% in ob/ob mice compared with their lean controls. The sensitivity of the present assay did not permit accurate determination of the low pancreatic concentrations of SP. The results suggest that the spontaneous ob/ob and db/db syndromes of obesity and diabetes in mice are associated with reduced intestinal concentrations of SP and NKA. The ob/ob mouse also exhibited reductions of intestinal GRP and pancreatic GRP and VIP concentrations. These changes in regulatory peptides may relate to abnormalities of intestinal and possibly pancreatic function in obese and diabetic mutant mice.  相似文献   

6.
The blood concentration of intact proinsulin, but not total proinsulin, has been suggested to be a diagnostic marker for type 2 diabetes mellitus (T2DM), but a sensitive assay specific for rodent intact proinsulin is lacking. Here, a novel enzyme-linked immunosorbent assay (ELISA) for mouse intact proinsulin was developed. The developed ELISA detected mouse intact proinsulin with the working range of 8.3 to 2700 pg/ml. Cross-reactivity with mouse split-32,33 proinsulin was approximately 100 times lower than the reactivity with mouse intact proinsulin, and no cross-reactivity with mouse insulin was detected. The developed ELISA was sufficiently sensitive to detect low levels of intact proinsulin in normal mouse plasma. The measurement by the developed ELISA revealed that intact proinsulin was elevated in the plasma of type 2 diabetic db/db mice as mice aged, and the ratio of intact proinsulin/insulin in plasma was correlated with levels of glycated hemoglobin A1c as seen in T2DM patients. These results suggest that the plasma level of intact proinsulin, but not total proinsulin, is a sensitive marker for pancreatic dysfunction and the ensuring diabetic disease progression of db/db mice. This ELISA could aid nonclinical evaluation of therapeutic interventions in T2DM.  相似文献   

7.

Expression of the diabetes (db/db) mutation in C57BL/KsJ mice results in functional suppression of the female pituitary-gonadal axis accompanied by premature utero-ovarian cytolipoatrophy. Cellular gluco- and lipo-metabolic disturbances promoted by the db/db systemic hyperglycemic-hyperinsulinemic state suppress pituitary gonadotropin release in response to gonadotropin-releasing hormone and gonadal steroid stimulation and results in a hypogonadal-infertility syndrome. Adult female C57BL/KsJ control (+/+ and +/? genotypes) and db/db littermates were monitored for associations in systemic and cellular alterations in luteinizing hormone (LH), follicle-stimulating hormone (FSH), gonadal steroid (binding) levels, and pituitary glucometabolic indices associated with db/db-enhanced lipid imbibition and cytostructural disruption. Obesity, hyperglycemia, and hyperinsulinemia characterized all db/db mutants relative to controls. Serum and pituitary progesterone and estradiol concentrations were suppressed in db/db mutants, in association with serum LH and FSH levels, but not with pituitary LH and FSH concentrations, which were comparable between groups. Pituitary insulin receptor binding and glucose utilization rates were suppressed in db/db groups relative to +/? indices. Structural and cytochemical analysis of anterior (AP), intermediate (IL), and neuro-(NP) hypophyseal lobes demonstrated prominent hypercytolipidemia in db/db mutants relative to controls. Prominent cytolipidemia was localized within well-granulated basophilic gonadotrophs and within IL and NP pituicytes. Vasolipidemia and interstitial cytoadiposity were prominent throughout all db/db pituitary lobes. Thus, disturbances associated with pituitary hypercytolipidemia are functional components of the expressed diabetes-associated hypogonadal syndrome in db/db mutants. Progressive alterations in hypophyseal cytoarchitecture are correlated with suppression of pituitary metabolic and endocrine indices, alterations that contribute to functional disruption of the pituitary-hypogonadal axis in C57BL/KsJ-db/db mice.

  相似文献   

8.
Insulin and nutrients activate hepatic p70 S6 kinase (S6K1) to regulate protein synthesis. Paradoxically, activation of S6K1 also leads to the development of insulin resistance. In this study, we investigated the effect of TRB3, which acts as an endogenous inhibitor of Akt, on S6K1 activity in vitro and in vivo. In cultured cells, overexpression of TRB3 completely inhibited insulin-stimulated S6K1 activation by mammalian target of rapamycin, whereas knockdown of endogenous TRB3 increased both basal and insulin-stimulated activity. In C57BL/6 mice, adenoviral overexpression of TRB3 inhibited insulin-stimulated activation of hepatic S6K1. In contrast, overexpression of TRB3 did not inhibit nutrient-stimulated S6K1 activity. We also investigated the effect of starvation, feeding, or insulin treatment on TRB3 levels and S6K1 activity in the liver of C57BL/6 and db/db mice. Both insulin and feeding activate S6K1 in db/db mice, but only insulin activates in the C57BL/6 strain. TRB3 levels were 3.5-fold higher in db/db mice than C57BL/6 mice and were unresponsive to feeding or insulin, whereas both treatments reduced TRB3 in C57BL/6 mice. Akt was activated by insulin alone in the C57BL/6 strain and but not in db/db mice. Both insulin and feeding activated mammalian target of rapamycin similarly in these mice; however, feeding was unable to activate the downstream target S6K1 in C57BL/6 mice. These results suggest that the nutrient excess in the hyperphagic, hyperinsulinemic db/db mouse primes the hepatocyte to respond to nutrients resulting in elevated S6K1 activity. The combination of elevated TRB3 and constitutive S6K1 activity results in decreased insulin signaling via the IRS-1/phosphatidylinositol 3-kinase/Akt pathway.  相似文献   

9.
Mice, 7–8-mo old, of the C57BL/KsJ-db strain and homozygotic for the mutant gene db, exhibited marked hyperglycemia and moderately elevated serum insulin levels. Light and electron microscopy provided evidence of a slightly decreased proportion of β cells in the pancreatic islets, irregular islet architecture with intraislet ducts, and degenerative as well as hypertrophic changes in the individual β cells. As a rule, islets microdissected from these mice did not release insulin in response to glucose, theophylline, iodoacetamide, or chloromercuribenzene-p-sulphonic acid. The absence of secretory responses was not simply due to lack of insulin. Although the islet content of insulin was decreased in C57BL/KsJ-db/db mice, the remaining amount was severalfold larger than that released from stimulated islets of normal controls. Another mutation, db2J, an allele of db with identical phenotypic expressions in the C57BL/KsJ strain, was studied on the genetic background C57BL/6J. In contrast to the severely diabetic C57BL/KsJ-db/db animals, the C57BL/6J-db2J/db2J mice were characterized by highly elevated serum insulin levels and only moderate hyperglycemia. Their endocrine pancreas was enlarged and showed an increased proportion of β cells. Like the islets of normal mice, those of C57BL/6J-db2J/db2J mice responded to glucose and chloromercuribenzene-p-sulphonic acid, the glucose-induced responses being potentiated by theophylline or iodoacetamide. C57BL/KsJ-db/db mice should provide a valuable model for studying defects in insulin secretion in relation to diabetes mellitus. Mice of the C57BL/6J strain offer a control material that may help to elucidate the dependence of the insulin secretory defect on the background genome.  相似文献   

10.
Ultrastructural characteristics as well as secretory and biosynthetic behavior of monolayer pancreatic cell cultures established from 4-day-old C57BL/KsJ misty diabetic (m db/m db) mice have been studied in comparison to normal littermate controls. Hypersecretion of glucagon by alpha-cells from BL/Ks misty diabetic mice after 2 days in vitro was found to precede any hyperfunction of the insulin-secreting beta-cells. The increased level of glucagon-release in BL/Ks cell cultures from diabetic mice was accompanied by a greatly enhanced level of incorporation of [3H]tryptophan into glucagon-like molecules whose specific radioactivity was up to 15-fold higher than that observed in cultures from genetic controls. The finding of an alpha-cell dysfunction in cultures established from preweaning diabetic BL/Ks mice suggests that glucagon could play an early role in shaping the events that culminate in the expression of frank diabetes in this inbred strain.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号