Beta cells, islet

Margulis, B.A., Sandler, S., Eizirik, D.L., Welsh, N., Welsh, M. (1991). Liposomal delivery of purified heat shock protein hsp70 in rat pancreatic islets as protection against interleukin I beta-induced impaired beta cell function. Diabetes 40, 1418-1422. 

Pharmacology Nateglinide lowers blood glucose levels by stimulating insulin secretion from the pancreas. This action is dependent upon functioning beta-cells in the pancreatic islets. 

Insulin is the anabolic hormone secreted by the beta cells of the pancreatic islets of Langerhans in response to increases in blood levels of glucose, amino acids, and fats after a meal. 

The answer is D. This student is still in the fed or absorptive state within 1 hour of a meal, so elevated levels of many nutrients derived from food digestion would be observed in her blood. This would include all items in the list except glucagon. High nutrient levels in the blood evoke increased insulin secretion from the beta cells and suppression of glucagon secretion by the alpha cells of the islets of Langerhans. Therefore, blood levels of glucagon would be decreased relative to other nutritional states. 

In their report the researchers describe a culturing technique that can turn mouse embryonic stem cells into cell clusters that resemble pancreatic islets. The clusters inner cells produced insulin, while outer cells produced glucagon and somatostatin, two other proteins typically synthesized by pancreatic cells. Most important, the embryonic stem cell-derived pancreas cells produce insulin in response to glucose, the fundamental role of beta cells that regulate insulin secretion. The major shortcoming of the system at this time is the low levels of insulin production. Refinements in culture technique or drug manipulation may be needed to achieve therapeutic levels. 

Kroncke, K.-D., Funda, J., Berschick, B., Kolb, H., and Kolb-Bachofen, V. (1991a). Macrophage cytocoxicity towards isolated rat islet cells Neither lysis nor its protection by nicotinamide are beta-cell specific. Diabetologia 34, 232-238. 

Inappropriate expression of class II MHC molecules on the membranes of cells that normally do not express class II MHC (eg, islet beta cells). Increased expression of MHC II may increase presentation of self peptides to T helper cells, which in turn induce CTL, TDTH, and B-lymphocyte cells that react against self antigens. 

Insulin target molecule in beta cells of human pancreatic islets of Langeihans... 

Amylin is a peptide hormone produced in the beta-cells of the islets of Langerhans and co-secreted with insulin. It has glucoregulatory effects that may complement the actions of insulin. 

GLP-1 increases beta-cell mass in animals. Thus, exenatide has the potential to cause increased beta-cell mass through augmented differentiation of precursor cells and inhibition of apoptosis (9). No malignant islet cell tumors were found in 130 mice and rats who received the... 

More direct interference with glucose metabolism cannot be excluded. Interferon alfa can reduce the sensitivity of peripheral tissues or liver to insulin and accelerate the destruction of stimulated pancreatic beta-cells (540,541) this could be a possible mechanism in patients not exhibiting islet cell antibodies. This is also in keeping with rare instances of induction or exacerbation of type II noninsulin dependent diabetes mellitus (SEDA-19, 335). 

Molnar E, Varadi A, Mcllhinney RA, Ashcroft SJ. Identification of functional ionotropic glutamate receptor proteins in pancreatic beta-cells and in islets of Langerhans. FEBS Lett 1995 371(3) 253-7. 

Insulin-dependent diabetes mellitus (IDDM) is an example of a metabolic disease under active consideration for inducible gene therapy strategies. In this disorder, inflammatory cytokines have been shown to activate apoptosis in pancreatic beta cells. Experimental studies indicate that expression of insulinlike growth factor-1 (IGF-1) can prevent the cytokine-mediated destruction of beta cells of the pancreas (Giannoukakis et al., 2001). Regulated expression of IGF-1 in human pancreatic islets, to preserve beta cell function, may be a useful approach in the treatment of certain types of diabetes (Demeterco and Levine, 2001). 

Giannoukakis, N., Mi, Z., Rudert, W.A., Gambotto, A., Trucco, M. and Robbins, P. (2001) Prevention of beta cell dysfunction and apoptosis activation in human islets by adenoviral gene transfer of the insulin-like growth factor I. Gene Ther., 7, 2015-2022. 

A relatively new approach in treating diabetes mellitus is the transplantation of tissues containing pancreatic beta cells into patients with this disease.73,109 For example, islet tissues containing functioning beta cells can be harvested from adult, neonatal, or fetal pancreatic... 

Kaneto, H., Kajimoto, Y., Fujitani, Y., Matsuoka, T., Sakamoto, K., Matsuhisa, M., Yamasaki, Y., and Hori, M. 1999. Oxidative stress induces p21 expression in pancreatic islet cell Possible implication in beta-cell dysfunction. Diabetologia 42, 1093-1097. 

Tolbutamide, N-[(butylamino)carbonyl]-4-methylbenzenesulphona-mide N-(butylamino) carbonyl-p-toluene sulphonamide is a sulphonlylurea that is orally active as a hypoglycemic agent. The drug stimulates the poncreatic islet beta cells to release extra insulin. It also inhibits phosphodiesterase, which preserves cyclic AMP and thus favor glycogenolysis in a number of tissues. 

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