Glucose Effectiveness Or Noninsulinmediated Glucose Uptake

It has been recognized for decades that insulin is an important hormone involved in the uptake of glucose into cells. Recently it has been demonstrated that glucose can stimulate its own uptake in the absence of insulin (Best et al 1996). This is known as 'glucose effectiveness' or non-insulin-mediated glucose uptake (NIMGU). Under fasting conditions, approximately 70% of glucose uptake occurs via glucose effectiveness, primarily in the central nervous system. After a meal, approximately 50% of glucose uptake in normal subjects occurs via NIMGU, the bulk of which occurs in skeletal muscle. Because many middle-aged subjects with diabetes are insulin-resistant, it has been suggested that up to 80% of postprandial glucose uptake in these patients may occur via glucose effectiveness. At this time it is uncertain whether defects contribute to elevated glucose levels in middle-aged patients with diabetes, since studies which have evaluated this parameter in middle-aged diabetics have given inconsistent results.

In healthy elderly subjects, glucose effectiveness is impaired during fasting but is normal during hypoglycemia (Meneilly et al 1989). Elderly patients with diabetes have an even greater impairment in glucose effectiveness than the healthy elderly (Figure 2.6)

Figure 2.6 Glucose effectiveness in elderly controls and patients with diabetes. During these studies, insulin secretion was suppressed by infusing the somatostatin analogue octreotide. Glucose was then infused to assess glucose disposal in the absence of insulin

(Forbes et al 1998). Although the cause of this abnormality is uncertain, it may relate to a decreased ability of glucose to recruit glucose transporters to the cell surface in these patients.

In the future, this metabolic abnormality may prove to be of great therapeutic relevance to the elderly. In younger patients, exercise, anabolic steroids and a reduction of free fatty acid levels have been shown to enhance glucose effectiveness (Best et al 1996). In preliminary experiments, the author's unit has shown that the incretin hormone glucagon-like-peptide-1 (GLP-1) may enhance NIMGU in elderly patients with diabetes. Thus, it is possible that future therapies for the elderly may be directed not only at increasing insulin secretion and reversing insulin resistance, but also at enhancing glucose effectiveness.

Supplements For Diabetics

Supplements For Diabetics

All you need is a proper diet of fresh fruits and vegetables and get plenty of exercise and you'll be fine. Ever heard those words from your doctor? If that's all heshe recommends then you're missing out an important ingredient for health that he's not telling you. Fact is that you can adhere to the strictest diet, watch everything you eat and get the exercise of amarathon runner and still come down with diabetic complications. Diet, exercise and standard drug treatments simply aren't enough to help keep your diabetes under control.

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