The Barrier of Hypoglycemia in Diabetes

Cryer, Philip E.

doi:10.2337/db08-1084

Cited by 640 publications

(612 citation statements)

References 47 publications

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“…This greater glucagon secretory response in our Mck/Gcgr mice may represent an important mechanism to compensate the glucagon trapping in the muscle in Mck/Gcgr mice. Interestingly, the adrenaline secretory response to the profound hypoglycaemia in both groups of mice was not statistically different, consistent with the notion that adrenaline, as the third physiological defence after insulin and glucagon, only becomes critical when the glucagon counter-regulatory response is impaired [31].…”

Section: Discussionsupporting

confidence: 66%

Ectopic expression of glucagon receptor in skeletal muscles improves glucose homeostasis in a mouse model of diabetes

et al. 2012

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Aims/hypothesis Excessive secretion of glucagon partially contributes to the development of diabetic hyperglycaemia. However, complete blocking of glucagon action will lead to adverse effects, since glucagon exerts certain beneficial effects via its receptor in many organs. We aimed to study the effects of a 'decoy receptor' for circulating glucagon on modulating beta cell function and glucose homeostasis in mice by over-producing the glucagon receptor (GCGR) in skeletal muscles. Methods We generated transgenic mice in which the expression of Gcgr is driven by the muscle specific creatine kinase (Mck) promoter, and assessed the effects of glucagon on the modulation of glucose homeostasis under conditions of extremes of glucose influx or efflux.Results Mck/Gcgr mice showed increased circulating levels of glucagon and insulin, resulting in an unchanged ratio of glucagon-to-insulin. The levels of hepatic glucose-6-phosphatase (G6PC) and fructose-1,6-bisphosphatase (F1,6P2ase) were significantly decreased, whereas the phosphorylation level of pancreatic cAMP-response-element-binding-protein (CREB) was significantly increased in these transgenic mice. Under basal conditions, the mice displayed normal blood glucose levels and unchanged glucose tolerance and insulin sensitivity when compared with their age-matched wild-type (WT) littermates. However, following multiple lowdose streptozotocin injections, Mck/Gcgr mice exhibited a delay in the onset of hyperglycaemia compared with the WT controls. This was associated with preserved beta cell mass and beta cell secretory capacity in response to glucose challenge.A. Maharaj and L. Zhu contributed equally to this study. Electronic supplementary material The online version of this article

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Section: Discussionsupporting

confidence: 66%

Ectopic expression of glucagon receptor in skeletal muscles improves glucose homeostasis in a mouse model of diabetes

et al. 2012

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“…Moreover, probably because of insulin's lipogenic and cholesterologenic actions, longterm insulin treatment is suspected to underlie the increased ectopic lipid deposition (i.e., in nonadipose tissues) (8) and incidence of coronary artery disease (>90% after the age of 55 y) (9, 10) seen in patients with T1D. Furthermore, in part attributable to insulin's potent, fast-acting, glycemia-lowering effects, intensive insulin therapy significantly increases the risk for hypoglycemia, an event that is disabling and can even be fatal (3,(11)(12)(13)(14). Therefore, despite the profound diabetes-improving and life-saving effects of insulin-based therapies, they do not restore metabolic homeostasis and may even lead to serious side effects.…”

mentioning

confidence: 99%

Leptin therapy improves insulin-deficient type 1 diabetes by CNS-dependent mechanisms in mice

Fujikawa

Chuang

Sakata

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

182

222

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Leptin monotherapy reverses the deadly consequences and improves several of the metabolic imbalances caused by insulindeficient type 1 diabetes (T1D) in rodents. However, the mechanism(s) underlying these effects is totally unknown. Here, we report that intracerebroventricular (icv) infusion of leptin reverses lethality and greatly improves hyperglycemia, hyperglucagonemia, hyperketonemia, and polyuria caused by insulin deficiency in mice. Notably, icv leptin administration leads to increased body weight while suppressing food intake, thus correcting the catabolic consequences of T1D. Also, icv leptin delivery improves expression of the metabolically relevant hypothalamic neuropeptides proopiomelanocortin, neuropeptide Y, and agouti-related peptide in T1D mice. Furthermore, this treatment normalizes phosphoenolpyruvate carboxykinase 1 contents without affecting glycogen levels in the liver. Pancreatic β-cell regeneration does not underlie these beneficial effects of leptin, because circulating insulin levels were undetectable at basal levels and following a glucose overload. Also, pancreatic preproinsulin mRNA was completely absent in these icv leptin-treated T1D mice. Furthermore, the antidiabetic effects of icv leptin administration rapidly vanished (i.e., within 48 h) after leptin treatment was interrupted. Collectively, these results unveil a key role for the brain in mediating the antidiabetic actions of leptin in the context of T1D.brain | leptin monotherapy | glucose homeostasis | glucagon suppression A ccording to the Juvenile Diabetes Research Foundation, type 1 diabetes (T1D) afflicts 1-3 million people in the United States alone. Regrettably, for reasons yet to be understood, the incidence of T1D has been increasing at an alarming annual rate of ∼3%, thus indicating that the number of patients with T1D is predicted to rise significantly in the future (1). T1D occurs as a consequence of pancreatic β-cell destruction leading to insulin deficiency, a defect that causes hyperglycemia, hyperglucagonemia, cachexia, ketoacidosis, and other abnormalities (2, 3). T1D is a deadly condition if not treated. Current life-saving interventions include daily insulin administration; insulin therapy reduces hyperglycemia, glycosylated hemoglobin, and cachexia and prevents or delays some T1D-associated morbidities (3, 4). However, even with insulin therapy, T1D secondary complications include debilitating and long-lasting conditions, such as heart disease, neuropathy, and hypertension (5-7). Moreover, probably because of insulin's lipogenic and cholesterologenic actions, longterm insulin treatment is suspected to underlie the increased ectopic lipid deposition (i.e., in nonadipose tissues) (8) and incidence of coronary artery disease (>90% after the age of 55 y) (9, 10) seen in patients with T1D. Furthermore, in part attributable to insulin's potent, fast-acting, glycemia-lowering effects, intensive insulin therapy significantly increases the risk for hypoglycemia, an event that is disabling and can even be fatal (3,(11...

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“…Hence, these agents cause severe and life-threatening hypoglycemias if not dosed very carefully. By the way round, to prevent hypoglycemias as far as possible, the target blood glucose level of the therapy with these agents is often chosen considerably above the physiological range so that fluctuations in the blood glucose level do not reach hypoglycemic values (Cryer 2008). This in turn however favours late complications.…”

mentioning

confidence: 99%

Chances and risks of SGLT2 inhibitors

Mayer

2011

Naunyn-Schmiedeberg's Arch Pharmacol

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The Barrier of Hypoglycemia in Diabetes

Cited by 640 publications

References 47 publications

Ectopic expression of glucagon receptor in skeletal muscles improves glucose homeostasis in a mouse model of diabetes

Ectopic expression of glucagon receptor in skeletal muscles improves glucose homeostasis in a mouse model of diabetes

Leptin therapy improves insulin-deficient type 1 diabetes by CNS-dependent mechanisms in mice

Chances and risks of SGLT2 inhibitors

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