scholarly journals Amylin found in amyloid deposits in human type 2 diabetes mellitus may be a hormone that regulates glycogen metabolism in skeletal muscle.

1988 ◽  
Vol 85 (20) ◽  
pp. 7763-7766 ◽  
Author(s):  
G. J. Cooper ◽  
B. Leighton ◽  
G. D. Dimitriadis ◽  
M. Parry-Billings ◽  
J. M. Kowalchuk ◽  
...  
2019 ◽  
Vol 126 (3) ◽  
pp. 626-637 ◽  
Author(s):  
Jefferson C. Frisbee ◽  
Matthew T. Lewis ◽  
Jonathan D. Kasper ◽  
Paul D. Chantler ◽  
Robert W. Wiseman

Despite extensive investigation into the impact of metabolic disease on vascular function and, by extension, tissue perfusion and organ function, interpreting results for specific risk factors can be complicated by the additional risks present in most models. To specifically determine the impact of type 2 diabetes without obesity on skeletal muscle microvascular structure/function and on active hyperemia with elevated metabolic demand, we used 17-wk-old Goto-Kakizaki (GK) rats to study microvascular function at multiple levels of resolution. Gracilis muscle arterioles demonstrated blunted dilation to acetylcholine (both ex vivo proximal and in situ distal arterioles) and elevated shear (distal arterioles only). All other alterations to reactivity appeared to reflect compromised endothelial function associated with increased thromboxane (Tx)A2 production and oxidant stress/inflammation rather than alterations to vascular smooth muscle function. Structural changes to the microcirculation of GK rats were confined to reduced microvessel density of ~12%, with no evidence for altered vascular wall mechanics. Active hyperemia with either field stimulation of in situ cremaster muscle or electrical stimulation via the sciatic nerve for in situ gastrocnemius muscle was blunted in GK rats, primarily because of blunted functional dilation of skeletal muscle arterioles. The blunted active hyperemia was associated with impaired oxygen uptake (V̇o2) across the muscle and accelerated muscle fatigue. Acute interventions to reduce oxidant stress (TEMPOL) and TxA2 action (SQ-29548) or production (dazmegrel) improved muscle perfusion, V̇o2, and muscle performance. These results suggest that type 2 diabetes mellitus in GK rats impairs skeletal muscle arteriolar function apparently early in the progression of the disease and potentially via an increased reactive oxygen species/inflammation-induced TxA2 production/action on network function as a major contributing mechanism. NEW & NOTEWORTHY The impact of type 2 diabetes mellitus on vascular structure/function remains an area lacking clarity. Using diabetic Goto-Kakizaki rats before the development of other risk factors, we determined alterations to vascular structure/function and skeletal muscle active hyperemia. Type 2 diabetes mellitus reduced arteriolar endothelium-dependent dilation associated with increased thromboxane A2 generation. Although modest microvascular rarefaction was evident, there were no other alterations to vascular structure/function. Skeletal muscle active hyperemia was blunted, although it improved after antioxidant or anti-thromboxane A2 treatment.


2014 ◽  
Vol 61 (3) ◽  
pp. 281-287 ◽  
Author(s):  
Kanako Shishikura ◽  
Keiji Tanimoto ◽  
Satoshi Sakai ◽  
Yoshimi Tanimoto ◽  
Jungo Terasaki ◽  
...  

2020 ◽  
Vol 57 (11) ◽  
pp. 1383-1393
Author(s):  
Qingqing Zhao ◽  
Jinxin Zhou ◽  
Yu Pan ◽  
Huijun Ju ◽  
Liying Zhu ◽  
...  

Abstract Aims Steroid diabetes mellitus (SDM) is a metabolic syndrome caused by an increase in glucocorticoids, and its pathogenesis is unclear. 18F-FDG PET/CT can reflect the glucose metabolism of tissues and organs under living conditions. Here, PET/CT imaging of SDM and type 2 diabetes mellitus (T2DM) rats was used to visualize changes in glucose metabolism in the main glucose metabolizing organs and investigate the pathogenesis of SDM. Methods SDM and T2DM rat models were established. During this time, PET/CT imaging was used to measure the %ID/g value of skeletal muscle and liver to evaluate glucose uptake. The pancreatic, skeletal muscle and liver were analyzed by immunohistochemistry. Results SDM rats showed increased fasting blood glucose and insulin levels, hyperplasia of islet α and β cells, increased FDG uptake in skeletal muscle accompanied by an up-regulation of PI3Kp85α, IRS-1, and GLUT4, no significant changes in liver uptake, and that glycogen storage in the liver and skeletal muscle increased. T2DM rats showed atrophy of pancreatic islet β cells and decreased insulin levels, significantly reduced FDG uptake and glycogen storage in skeletal muscle and liver. Conclusions The pathogenesis of SDM is different from that of T2DM. The increased glucose metabolism of skeletal muscle may be related to the increased compensatory secretion of insulin. Glucocorticoids promote the proliferation of islet α cells and cause an increase in gluconeogenesis in the liver, which may cause increased blood glucose.


2017 ◽  
Vol 313 (3) ◽  
pp. R290-R297 ◽  
Author(s):  
K. M. Fanning ◽  
B. Pfisterer ◽  
A. T. Davis ◽  
T. D. Presley ◽  
I. M. Williams ◽  
...  

Radiation exposure accelerates the onset of age-related diseases such as diabetes, cardiovascular disease, and neoplasia and, thus, lends insight into in vivo mechanisms common to these disorders. Fibrosis and extracellular matrix (ECM) remodeling, which occur with aging and overnutrition and following irradiation, are risk factors for development of type 2 diabetes mellitus. We previously demonstrated an increased incidence of skeletal muscle insulin resistance and type 2 diabetes mellitus in monkeys that had been exposed to whole body irradiation 5–9 yr prior. We hypothesized that irradiation-induced fibrosis alters muscle architecture, predisposing irradiated animals to insulin resistance and overt diabetes. Rhesus macaques ( Macaca mulatta, n = 7–8/group) grouped as nonirradiated age-matched controls (Non-Rad-CTL), irradiated nondiabetic monkeys (Rad-CTL), and irradiated monkeys that subsequently developed diabetes (Rad-DM) were compared. Prior radiation exposure resulted in persistent skeletal muscle ECM changes, including a relative overabundance of collagen IV and a trend toward increased transforming growth factor-β1. Preservation of microvascular markers differentiated the irradiated diabetic and nondiabetic groups. Microvascular density and plasma nitrate and heat shock protein 90 levels were lower in Rad-DM than Rad-CTL. These results are consistent with a protective effect of abundant microvasculature in maintaining glycemic control within radiation-induced fibrotic muscle.


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