Influence of acetylsalicylic acid on plasma glucose, insulin, glucagon, and growth hormone levels following tolbutamide stimulation in man

Effects of chronic sodium salicylate feeding on the impaired glucagon and epinephrine responses to insulin-induced hypoglycaemia in streptozotocin diabetic rats

The potential role of endogenous prostaglandins in glucagon and epinephrine responses to insulin-induced hypoglycaemia was studied in streptozotocin-diabetic and age-matched control adult male rats. Rats made diabetic with a single intravenous injection of streptozotocin (65 mg/kg) developed impaired glucagon and epinephrine responses to insulin-induced hypoglycaemia by 80-100 days. Plasma glucagon levels in response to insulin-induced hypoglycaemia in streptozotocin-diabetic rats (167 +/- 67 pg/ml) were significantly lower (p less than 0.01) than those in control rats (929 +/- 272 pg/ml). Similarly, plasma epinephrine levels in hypoglycaemic state in streptozotocin-diabetic rats (11 +/- 8 pmol/ml) were also significantly lower (p less than 0.01) compared to control rats (37 +/- 13 pmol/ml). Streptozotocin-diabetic rats provided with sodium salicylate (25 mg/100 ml) in their drinking water from day one of diabetes exhibited prevention of the blunted glucagon and epinephrine responses to insulin-induced hypoglycaemia. About 80-100 days after the chronic sodium salicylate treatment in streptozotocin-diabetic rats, both plasma glucagon levels (1080 +/- 169 pg/ml) and plasma epinephrine levels (39 +/- 8 pmol/ml) were essentially identical to plasma glucagon levels (1074 +/- 134 pg/ml) and plasma epinephrine levels (37 +/- 5 pmol/ml) in control rats in hypoglycaemic state. These animals also exhibited an improvement in the diabetic state in that they had less severe hyperglycaemia and lack of weight gain. These results suggest that the blunted glucagon and epinephrine responses to insulin-induced hypoglycaemia may be related to altered prostaglandin levels in streptozotocin-diabetes.

Sodium salicylate restores the impaired insulin response to glucose and improves glucose tolerance in heroin addicts

Plasma glucose, insulin, C-peptide, glucagon and growth hormone responses to intravenous glucose were evaluated in 10 heroin addicts in the basal state and during an infusion of sodium salicylate, an inhibitor of endogenous prostaglandin synthesis. Ten normal subjects, matched for age, sex and weight served as controls. In the basal state, the heroin addicts had markedly reduced insulin responses to intravenous glucose and low glucose disappearance rates (p less than 0.01 vs controls). The infusion of sodium salicylate caused a striking increase of the acute insulin response to intravenous glucose (from 14.5 +/- 4 microU/ml to 88 +/- 11 microU/ml, p less than 0.001) and restored to normal the reduced glucose tolerance (KG from 1.10 +/- 0.1% min-1 to 2.04 +/- 0.19% min-1). Hypoglycemic values were found in all addicts at the end of the test during salicylate infusion. Indomethacin pretreatment in five additional addicts also caused normalization of the impaired insulin responses to the intravenous glucose challenge and restored to normal the reduced glucose disappearance rate. Plasma glucagon and growth hormone levels were normally suppressed by glucose in addicts in basal conditions; sodium salicylate infusion completely overturned these hormonal responses which became positive in the first 15 min following the glucose challenge. These results demonstrate that the two prostaglandin synthesis inhibitors can restore the impaired B-cell response to glucose in heroin addicts to normal, indicating that this response is not lost but is inhibited by heroin itself or by other substances, perhaps by the endogenous prostaglandins.

Glucose metabolism in patients with rheumatoid arthritis

Several studies made during the first half of this century suggested an association between chronic arthritis and disturbed glucose metabolism. Moreover, increased prevalence of IGT in patients with idiopathic FTS of the palms has recently been reported and RA is a disease commonly accompanied by FTS. Furthermore, patients with RA are often exposed to drugs that may precipitate or uncover mild undiagnosed DM. For these reasons, glucose tolerance was studied in 101 patients with classical or definite RA. Of these, 4 (4%) had an established type II DM and 6 (6%) a previously undiagnosed IGT. The observed frequencies of disturbed glucose metabolism in RA did not differ from the prevalence rates reported for the general population in Sweden. Hence, this study does not support the previous reports claiming an association between chronic arthritis and disturbed glucose metabolism.

A role for endogenous prostaglandin E in biphasic pattern of insulin release in humans

These studies were undertaken to evaluate in humans the possible physiological role of prostaglandins of the E series (PGE) in modulating insulin release and to assess whether endogenous PGE synthesis may account for the biphasic pattern of insulin secretion. We used a square-wave glucose stimulation previously determined to give maximal biphasic insulin release. Infusion of lysine acetylsalicylate to block the synthesis of endogenous PGE increased by twofold total insulin response to glucose and also converted insulin release to a multiphasic pattern. The infusion of exogenous PGE1 (0.2 microgram X kg-1 X min-1) or PGE2 (10 micrograms/min) in addition to lysine acetylsalicylate restored the typical biphasic pattern of insulin release and also decreased total insulin release to values similar to those of control studies. Infusion of either PGE1 or PGE2 in the absence of lysine acetylsalicylate reset insulin secretion to a lower level without altering the kinetics of release. On the basis of these results, it is hypothesized that endogenous PGE released in response to glucose stimulation exert an inhibiting effect on insulin release that becomes biphasic in appearance.

Glucose tolerance and hormonal responses in heroin addicts. A possible role for endogenous opiates in the pathogenesis of non-insulin-dependent diabetes

Plasma glucose, insulin, glucagon, and growth hormone responses to intravenous glucose stimulation were investigated in 15 heroin-dependent men and in 15 control subjects matched for age, sex, and weight. Although the fasting concentrations of insulin, glucagon, and GH were significantly higher in the heroin addicts, they had markedly reduced plasma insulin responses to intravenous glucose (acute insulin response, calculated as the mean change in insulin levels over 3 to 10 minutes: 10 +/- 5 microU/mL in the addicts v 44 +/- 9 microU/mL in the controls, P less than 0.001) and glucose utilization rates in the diabetic range (KG: 0.96 +/- 0.09%/min in the addicts v 1.65 +/- 0.10%/min in the controls, P less than 0.01). These results show that chronic heroin administration produces a state of fasting hyperinsulinemia even in the absence of obesity, glucose intolerance, and a marked reduction of the first phase of insulin secretion. A possible role for endogenous opiates in the pathogenesis of non-insulin-dependent diabetes is hypothesized.

Effect of acetylsalicylic acid on blood glucose and glucose regulatory hormones in mild diabetes

In order to investigate the effect of acetylsalicylic acid (ASA) on glucose tolerance and glucose regulatory hormones, ASA was given to 14 diabetic patients for seven days by two different methods. A 50 g oral glucose tolerance test (OGTT) was performed before and after the treatment. Nine of 14 diabetics received a dosage of 1.5 g of ASA three times a day for seven days plus 1.5 g on the eighth day one hr before the test (group I). The other 5 patients had the same dosage of ASA as group I, but were not administered ASA prior to the second OGTT (group II). In group I the ASA treatment improved the glucose tolerance associated with sustained rise of plasma insulin significantly, whereas no significant change in glucose tolerance or plasma insulin was observed in group II compared the pretreatment level. The ASA had no significant effect on plasma glucagon or gastric inhibitory polypeptide in either group I or group II. These results suggest that ASA allievates glucose intolerance in maturity onset diabetics by a direct enhancement of insulin secretion, and, moreover, that it is important to maintain elevated ASA concentrations in their blood.

Prostaglandins and the alpha-cell

Experimental evidence has recently accumulated indicating that administration of some prostaglandins (PGs), particularly those of the E series, can evoke release of glucagon by the pancreatic alpha-cells. Virtually, all the in vitro studies (isolated perfused rat pancreas, isolated guinea-pig islets) agree that PGs can increase both basal and stimulated glucagon release. On the other hand, inhibition of PG synthesis with indomethacin blocks glucagon release. In rats and in normal humans, PGE1, but not PGA2 or PGF2a, causes a progressive rise of plasma glucagon levels. While in the rat this response seems independent of the adrenergic nervous system, in man the hyperglucagonemia induced by PGE1 is easily suppressed by propranolol, suggesting an interaction between the prostaglandin and the beta-receptors of the alpha-cell. Studies with inhibitors of PG synthesis in vivo have yielded conflicting results, depending on the particular experimental protocol used and on the type of inhibitor tested. In normal humans, it seems that acetylsalicylic acid (ASA) has no effect on glucagon response to arginine, tolbutamide and insulin-induced hypoglycemia. Conversely, a stimulator of PG synthesis, such as furosemide, increases glucagon response to an arginine pulse in man. In insulin-dependent diabetics, who present an exaggerated glucagon response to stimulants, ASA fails to alter glucagon response to arginine, but completely blunts the glucagon response to salbutamol, a weak beta-2 receptor agonist. In conclusion, these observations provide evidence in support to a role for PGs, at least PGE, in the contro of glucagon release.

Impaired insulin secretion in human diabetes mellitus. II. A possible role for prostaglandins

Human diabetes mellitus is characterized by impaired insulin response to intravenous glucose. In search of possible endogenous factors which impair insulin release, we have investigated the effect of lysine acetylsalicylate (LAS), an inhibitor of endogenous prostaglandin (PGs) synthesis, upon insulin responses to glucose and arginine in subjects with type II (adult-on-set) diabetes mellitus. Acute insulin response to glucose (20 g) was significantly increased by LAS (response before LAS=26 +/- 10%; during LAS=77+15%, mean+/-SEM, mean change 3-10 min insulin, % basal, n=8, p 0.01), as well as second phase insulin secretion (before LAS=1437+/-316%; during LAS=3960+/-550%, change 10-60 min, uU/ml-min, % basal, p less than 0.01). This effect was associated with an increase in glucose disappearance rates (p less than 0.01). Acute insulin response to arginine (5 g iv) was also increased by LAS infusion. These results suggest that endogenous PGs may be one of the factors which impair insulin secretion in human diabetes.