Glucose, insulin and somatostatin infusion for the determination of insulin resistance in liver cirrhosis

Twelve patients with liver cirrhosis and ten normal subjects were studied. Using a constant intravneous infusion of glucose, insulin and somatostatin over 2 1/2 hours we determined the stteady state plasma glucose level (SSPG) in order to measure insulin resistance. The results demonstrated that the cirrhotic patients were insulin resistant compared to normals and that plasma glucagon does not account for the insulin resistance in these patients.

Gastrin response to insulin in patients with cirrhosis of the liver

Fasting gastrinemia in cirrhotics (48.35 +/- 2.77 pg/ml) was higher than in normal controls (32.93 +/- 0.75 pg/ml; P less than 0.001). After insulin-induced hypoglycemia, the mean increase of gastrin above basal level was 42.29 +/- 1.92 pg/ml in controls and 10.85 +/- 5.05 pg/ml in cirrhosis (P less than 0.001). BAO was 2.53 +/- 0.36 mEq/h in controls and 0.42 +/- 0.004 mEq/h in cirrhotics (P less than 0.001). After i.v. insulin, TAO was 8.42 +/- 0.72 mEq/h in controls and 3.06 +/- 0.26 mEq/h in cirrhotics (P less than 0.001). The authors suggest that the lack of an adequate gastrin and acid response to the hypoglycemic stimulus in cirrhotics might be accounted for by a decreased insulin sensitivity.

Effect of somatostatin (SRIF) on plasma glucose and insulin response to glucagon in liver cirrhosis

The present study was performed in order to evaluate the plasma glucose pattern in cirrhotic patients who, in the course of a continuous somatostatin infusion (500 microgram/h), were given pulses of glucagon (1 mg i.v.). In normal as well as in cirrhotic subjects somatostatin infusion provoked a marked reduction of the IRI plasma level and this was uninfluenced by subsequent glucagon administration. The rise in plasma glucose level in response to i.v. glucagon administration during somatostatin infusion was less marked in cirrhotics compared to normal subjects. This can be attributed to a variety of factors such as reduced number of liver cells or quantitative or qualitative changes of the liver cell glucagon receptors. Glucagon does not seem to contribute to the pathogenesis of carbohydrate intolerance in liver cirrhosis.

Serum gastrin in portal and peripheral veins after arginine in man

Immunoreactive serum gastrin from portal and peripheral veins was determined in five controls and in five cirrhotic patients with indwelling portal catheters in basal conditions, during and after 30 min arginine infusion, in order to assess whether the human liver is involved in gastrin metabolism. A significant difference was found between portal and peripheral gastrin concentrations in controls at 0, 60 and 90 min; no significant differences were found in cirrhotics. Our findings support the hypothesis of an at least partial breakdown of endogenous gastrin in the human liver.

The effect of food intake on insulin receptor in man

Insulin binding to circulating monocytes was studied in 22 normal volunteers before and 1, 3 and 5 h after a 1400 Kcal meal. Results indicate that 3 h after food intake there is an increase in the specific cell binding fraction (P less than 0.001) with a change in receptor affinity. Data emerging from the present study demonstrate that there are rapid changes in insulin receptor properties during the day. These changes probably play a role in the regulation of the hormonal and metabolic pattern in normal subjects.

Early insulin and glucagon response to subsequent pulses of arginine, glucose, and tolbutamide in normal man

To determine the dynamics of insulin and of glucagon secretion in response to several sequential stimuli administered shortly after an arginine pulse (5 g), 20 nonobese, apparently healthy volunteers were given arginine (5 g), glucose (5 g), and tolbutamide (1 g) by rapid intravenous injection. The early insulin and glucagon area 0-8 min was studied. At the intervals and with the dosages used in this study, different stimuli with and without prestimulation with arginine did not lead to changes in early secretion of insulin. There was no exhaustion of the pool of insulin released after multiple sequential pulses. These results suggest a pattern in which stimulation induces a rapid release of insulin and activates the interchange between the stored and labile insulin pool; the 8-min interval is sufficient for the rapid return of the two compartments to a state of equilibrium. Also for glucagon, subsequent different stimuli did not exhaust glucagon release; nevertheless, glucagon is immediately suppressed by a submaximal glucose pulse.

Effects of insulin on hepatic lipid synthesis in alloxan diabetic rats

In vitro hepatic synthesis of lipids starting from 1-(14)C-acetate was studied in rats made diabetic by subcutaneous alloxan administration (175 mg/kg b.w.). A second group of diabetic rats was treated with lente insulin. In the alloxan-treated rats, a decrese was observed in hepatic incorporation of 1-(14)C-acetate into phospholipids, triglycerides and esterified cholesterol; there was an increased incorporation into nonesterified fatty acids (NEFA) and free cholesterol. Insulin administration restored lipid synthesis values to normal. On histologic examination, an intranuclear glycogenesis was observed in the hepatocytes of the alloxan-treated rats, along with severe hepatic necrosis; the latter however, only in rats sacrified on the 3rd day. Hepatic steatosis with small, medium and large droplets was present in the insulin-treated rats; signs of cellular degeneration were less evident.

GH secretion in open-angle glaucoma

Open-angle glaucoma is frequently observed in patients with acromegaly suggesting that the somatotropic hormone might facilitate a condition of glaucoma. The open-angle glaucoma patients studied, displayed higher plasma human growth hormone (HGH) levels than control subjects 60 min (30.3 +/- 1.7 against 16.8 +/- 2.7 ng/ml; p less than 0.001) and 90 min (19.0 +/- 1.9 against 9.3 +/- 1.2 ng/ml; p less than 0.001) after intravenous administration of arginine (25 g in 30 min). The authors support the hypothesis that the increased plasma HGH level may interfere with the regulation of ocular pressure by modifying the flow of aqueous humor from the eyeball via changes in the sclero-corneal trabecular meshwork; these changes are also found in diabetic subjects. The interplay between HGH and changes of carbohydrate metabolism (frequently occurring in glaucomatous patients) may be at the root of the variations of intraocular pressure in open-angle glaucoma.

Insulin receptors during the menstrual cycle in normal women

Specific binding of 125I-insulin to circulating monocytes from eight normal menstruating women, four postmenopausal women and four men were studied four times during a 28-day period (one sample at 7-day intervals). Data indicate the presence of a higher specific cell binding fraction in the follicular phase compared to the luteal phase due to changes in insulin receptor concentration. No changes were observed in men or postmenopausal women during the same period of time suggesting that sex hormones should be included among the factors influencing insulin receptors.

Urinary kallikrein excretion and plasma DBH activity in hypertension

Many factors are to be considered in maintaining normal blood pressure. Authors study the behavior of urinary kallikrein (U.K.) and plasma dopamine-beta-hydroxylase (DBH) activity in various forms of hypertension. The values of U.K. excretion in normals were 20.5 +/- 1.8 E.U./24 h. In essential hypertensive patients (9.4 +/- 2.0 E.U./24 h) U.K. decreased, while in secondary hypertension it was significantly higher (33.8 +/- 3.0 E.U./24 h). Plasma DBH activity in essential hypertensive patients (17.72 +/- 2.33 I.U./ml) was similar to controls (20.22 +/- 1.39 I.U./ml); in secondary hypertension the mean values of plasma DBH were decreased (12.31 +/- 2.55 I.U./ml). No correlation between U.K. and plasma DBH activity was observed in normals and in various forms of hypertensive patients. U.K. seems a more reliable factor than plasma DBH in defining the different types of hypertension.

[Behavior of plasma/insulin, somatropin and NEFA after intravenous administration of tolbutamide in hepatic cirrhosis]

Cirrhotics presented higher insulin production, in the presence of a drop in glycaemia significantly less than controls, following 1 g of tolbutamide i.v. The drug also brought on a rapid drop in NEFA and a rise in plasma growth hormone. The pathogenesis of altered glucose tolerance in liver cirrhosis is discussed.

[Changes in plasma insulin and growth hormone after intravenous glucagon in hepatic cirrhosis]

Decreased increases in blood sugar by comparison with control subjects was noted in patients with cirrhosis of the liver after i.v. administration of 1 mg glucagon. Insulin secretion was similar to that observed in the controls. Basal GH values were higher in the liver patients, whereas after glucagon they displayed a gradual and progressive increase with a peak at 60'. No significant differences in GH pattern were noted in the two groups, however.

[GH secretion after L-dopa administration in hepatic cirrhosis]

A 500 mg L-Dopa administration in normal and cirrhotic subjects does not determinate a significant varation of plasma glucose and insulin level, while a peak plasma GH level in both cirrhotic and normal subjects occurred at 90' with a significantly greates values in cirrhotics. It is doubtful to affirm that a high plasma GH level is the only one factor which responsable of glucose intolerance in cirrhotic subjects, when there are many others factors contribute to it in synergic way. In order to elucidate the hypothesis on possible pathogenetic mechanism it is discussed some of our own experience and observations.

[Secretion of GH and diabetic retinopathy]

Recently it has been studied a possible pathogenetic role of GH in diabetic angiopathy. The purpose of the present study was to verify whether the diabetic retinopathy is associated or not with a high plasma GH level. In an attempt to answer this question we did the dosage of plasma GH after a oral glucose load (110 g), Insulin (0,1 U/Kg) i.v., and arginin i.v. (25 g/30'). The plasma GH measurements were approximately the same as in normal patients. The Authors underline the importance of GH in pathophysiology of diabetic angiopathy and report all recent literature on this argument.

[Plasma insulin and GH during oral glucose load in liver cirrhosis]

Blood sugar, insulin and GH values were examined in two groups of cirrhosis of the liver patients, with and without ascites, after the administration of 100 g glucose per os. No significant differences between the two groups were observed. Insulin values were higher than those in the controls, with a pattern similar to that noted in subjects with chemical diabetes. GH values were higher than in normal subjects and secretion was not suppressed.

[Simple glaucoma and diabetic disease]

Blood sugar, blood insulin and the insulinogenic index after oral glucose were studied in 41 subjects with simple glaucoma. Clinical diabetes was present in 9.76% and asymptomatic diabetes in 21.95%. It is suggested that a high incidence of diabetes may be expected in simple glaucoma, probably as expressions of a common genetic disorder.

[The association of diabetic disease with Friedreich's disease in members of the same family]

Friedreigh's disease is only rarely associated with diabetes mellitus and only few cases are to be found in the literature, especially as regards siblings. Three cases of this association in members of two different families are reported. Two of the patients died from cardiovascular complication; the third case is that of a 32-yr-old woman who was able to complete a pregnancy. The pathogenesis of the association is discussed and a number of theories are put forward. The most generally accepted genetic hypothesis makes it possible to explain under a common metabolic denominator neurological disturbances and those in other systems. The association is not a purely casual event but is perhaps dependent on either two different genes or on a single gene with pleitropic effect. Heart signs are frequent in Friedreich's disease and brief mention is made of these.

[Urinary kallikrein excretion in hepatic cirrhosis]

Measurements of urinary kallikrein using an esterolytic assay revealed higher levels in patients with liver cirrhosis than in a control population. The range of excretion in 33 patients with cirrhosis was from 18.68 to 85.20 E.U. per 24 hours with a mean excretion of 39.42 plus or minus 2.84 E.U. Kallikrein excretion in the control group ranged from 13.20 to 39.50 E.U. per 24 hours with a mean of 24.44 plus or minus 1.66 E.U.