Letters to the Editor

PEDIATRICS ◽  
1968 ◽  
Vol 42 (2) ◽  
pp. 371-372
Author(s):  
Marvin Cornblath ◽  
Allan Drash
Keyword(s):  
Islet Cell ◽  
Plasma Insulin ◽  
Letters To The Editor ◽  
Cell Adenoma ◽  
Insulin Levels ◽  
Fasting Plasma ◽  
Portal Plasma ◽  
Plasma Insulin Levels

In reply to Dr. Ehrlich's questions, we only wish that life would be as simple as he implied. The association of increased peripheral venous insulin values with islet cell adenoma is by no means universal in adults. In a child with multiple islet cell adenomata (Pediatrics, 39:59, 1967) , fasting plasma insulins as well as those following glucose, tolbutamide, and leucine, were not abnormally elevated. No other studies of peripheral or portal plasma insulin levels in infants or children with islet cell adenoma are known to us.

Strength training increases insulin action in healthy 50- to 65-yr-old men

1994 ◽  
Vol 77 (3) ◽  
pp. 1122-1127 ◽  
Author(s):  
J. P. Miller ◽  
R. E. Pratley ◽  
A. P. Goldberg ◽  
P. Gordon ◽  
M. Rubin ◽  
...  
Keyword(s):  
Strength Training ◽  
Insulin Action ◽  
Plasma Insulin ◽  
Insulin Infusion ◽  
Glucose Clamp ◽  
Oral Glucose ◽  
Insulin Levels ◽  
Glucose Levels ◽  
Fasting Plasma ◽  
Plasma Insulin Levels

The insulin resistance associated with aging may be due, in part, to reduced levels of physical activity in the elderly. We hypothesized that strength training increases insulin action in older individuals. To test this hypothesis, 11 healthy men 50–63 yr old [mean 58 +/- 1 (SE) yr] underwent a two-step hyperinsulinemic-euglycemic glucose clamp with concurrent indirect calorimetry and an oral glucose tolerance test (OGTT) before and after 16 wk of strength training. The training program increased overall strength by 47% (P < 0.001). Fat-free mass (FFM; measured by hydrodensitometry) increased (62.4 +/- 2.1 vs. 63.6 +/- 2.1 kg; P < 0.05) and body fat decreased (27.2 +/- 1.8 vs. 25.6 +/- 1.9%; P < 0.001) with training. Fasting plasma glucose levels and glucose levels during the OGTT were not significantly lower after training. In contrast, fasting plasma insulin levels decreased (85 +/- 25 vs. 55 +/- 10 pmol/l; P < 0.05) and insulin levels decreased (P < 0.05, analysis of variance) during the OGTT. Glucose infusion rates during the hyperinsulinemic-euglycemic glucose clamp increased 24% (13.5 +/- 1.7 vs. 16.7 +/- 2.2 mumol.kg FFM-1.min-1; P < 0.05) during the low (20 mU.m-2.min-1) insulin infusion and increased 22% (55.7 +/- 3.3 vs. 67.7 +/- 3.9 mumol.kg FFM-1.min-1; P < 0.05) during the high (100 mU.m-2.min-1) insulin infusion. These increases were accompanied by a 40% increase (n = 7; P < 0.08) in nonoxidative glucose metabolism during the high insulin infusion. These results demonstrate that strength training increases insulin action and lowers plasma insulin levels in middle-aged and older men.

scholarly journals Evidence that GLUT-2 mRNA and protein concentrations are decreased by hyperinsulinaemia and increased by hyperglycaemia in liver of diabetic rats

1992 ◽  
Vol 288 (2) ◽  
pp. 675-679 ◽  
Author(s):  
R Burcelin ◽  
M Eddouks ◽  
J Kande ◽  
R Assan ◽  
J Girard
Keyword(s):  
Blood Glucose ◽  
Plasma Insulin ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Insulin Infusion ◽  
Pancreatic Beta Cell ◽  
Diabetic Rats ◽  
Mrna Levels ◽  
Insulin Levels ◽  
Portal Plasma ◽  
Plasma Insulin Levels

GLUT-2, glucokinase (GK) and phosphoenolpyruvate carboxykinase (PEPCK) mRNA expression was studied in the liver of chronically catheterized diabetic rats during the 3 days after an intravenous injection of 65 mg of streptozotocin (STZ)/kg. At 6 h after the STZ injection, portal plasma insulin levels were 270 +/- 32 mu-units/ml and blood glucose was 1.4 +/- 0.4 mmol/l, owing to pancreatic beta-cell destruction. GLUT-2 and PEPCK mRNA concentrations were rapidly and dramatically decreased (> 90%), whereas GK mRNA was increased. After 30 h, plasma insulin concentrations were lower than 5 mu-units/ml and blood glucose was > 20 mmol/l. GLUT-2 and PEPCK mRNA concentrations increased 2-fold and GK mRNA disappeared progressively. In order to assess the relative roles of hyperglycaemia and insulinopenia, blood glucose was clamped at 6.4 +/- 0.5 mmol/l from 18 to 72 h after STZ injection by phlorizin infusion (0.5-2 g/day per kg) or at 6.6 +/- 0.3 mmol/l from 18 to 48 h after STZ injection by insulin infusion (0.25 unit/min per kg). GLUT-2 mRNA concentrations were 50% lower in phlorizin-infused than in untreated diabetic rats. The low levels of GK mRNA and the high levels of PEPCK mRNA were unaffected by normalization of hyperglycaemia in phlorizin-infused diabetic rats. In insulin-infused rats (portal plasma insulin levels of 40 mu-units/ml) GLUT-2 mRNA levels were 25% of those in untreated diabetic rats, and they increased rapidly 6 h after insulin infusion was stopped. Liver GLUT-2 protein concentration showed similar changes in response to STZ injection and to phlorizin or insulin treatment, but after a delay of several hours. From this work we conclude that GLUT-2 gene expression is dramatically and rapidly (< 6 h) decreased by portal hyperinsulinaemia and increased by hyperglycaemia.

scholarly journals Lower plasma insulin levels during overnight closed-loop in school children with type 1 diabetes: Potential advantage? A randomized cross-over trial

PLoS ONE ◽  
2019 ◽  
Vol 14 (3) ◽  
pp. e0212013 ◽  
Author(s):  
Ulrike Schierloh ◽  
Malgorzata E. Wilinska ◽  
Ineke M. Pit-ten Cate ◽  
Petra Baumann ◽  
Roman Hovorka ◽  
...  
Keyword(s):  
Type 1 Diabetes ◽  
School Children ◽  
Plasma Insulin ◽  
Closed Loop ◽  
Lower Plasma ◽  
Insulin Levels ◽  
Plasma Insulin Levels

Metformin decreases plasma insulin levels and systolic blood pressure in spontaneously hypertensive rats

1994 ◽  
Vol 267 (4) ◽  
pp. H1250-H1253 ◽  
Author(s):  
S. Verma ◽  
S. Bhanot ◽  
J. H. McNeill
Keyword(s):  
Blood Pressure ◽  
Systolic Blood Pressure ◽  
Spontaneously Hypertensive Rats ◽  
Plasma Insulin ◽  
Metformin Treatment ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Insulin Levels ◽  
Plasma Insulin Levels ◽  
Wistar Kyoto

To determine the relationship between hyperinsulinemia and hypertension in spontaneously hypertensive rats (SHR), the antihyperglycemic agent metformin was administered to SHR and their Wistar-Kyoto (WKY) controls, and its effects on plasma insulin levels and blood pressure were examined. Five-week-old rats were started on oral metformin treatment (350 mg.kg-1.day-1, which was gradually increased to 500 mg.kg-1.day-1 over a 2-wk period). Metformin treatment caused sustained decreases in plasma insulin levels in the SHR (27.1 +/- 2.3 vs. untreated SHR 53.5 +/- 2.7 microU/ml, P < 0.001) without having any effect in the WKY (30.7 +/- 2.2 vs. untreated WKY 37.8 +/- 1.6 microU/ml, P > 0.05). The treatment did not affect the plasma glucose levels in any group. Metformin treatment also attenuated the increase in systolic blood pressure in the SHR (157 +/- 6.0 vs. untreated SHR 196 +/- 9.0 mmHg, P < 0.001) but had no effect in the WKY (134 +/- 3 vs. untreated WKY 136 +/- 4 mmHg, P > 0.05). Furthermore, raising plasma insulin levels in the metformin-treated SHR to levels that existed in the untreated SHR reversed the effect of metformin on blood pressure (189 +/- 3 vs. untreated SHR 208 +/- 5.0 mmHg, P > 0.05). These findings suggest that either hyperinsulinemia may contribute toward the increase in blood pressure in the SHR or that the underlying mechanism is closely associated with the expression of both these disorders.

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