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F Lignon

Publications and source records attributed to F Lignon.

11 recordsLinked to original sources
PubMed1980

Different effects of hypothermia on insulin and glucagon secretion from the isolated perfused rat pancreas.

Two series of experiments with the isolated perfused rat pancreas were performed in parallel. The conditions differed only with respect to temperature, which was 37.5 degrees C in one series and 28 degrees C in the other. The lowering of the temperature decreased insulin secretion induced by glucose as well as the insulin response to tolbutamide and acetylcholine. Unlike insulin, glucagon secretion was not significantly modified by hypothermia. Our results suggest that the mechanisms involved in glucagon and insulin secretion are different.

Acetylcholine↗
PubMed1979

Structural specificity of nucleotides for insulin secretory action from the isolated perfused rat pancreas.

The study concerned the effects of variuos nucleotides on the insulin secretion from the isolated perfused rat pancreas. ATP, the first nucleotide studied, increased the insulin release induced by glucose 1.5 g/l. There was a first immediate peak followed by a second significant and durable increase. The log dose-response curve was linear for concentrations ranging from 0.825 microM to 330 microM. The effects of natural adenine derivatives (ATP, ADP, 5' AMP, cAMP and adenosine) were compared. ATP was the most active compound; ADP had nearly the same activity as ATP (relative potency ATP/ADP = 3.2); 5' AMP, cAMP and adenosine displayed a very weak activity (about 100 fold less active). Adenylimido-diphosphate (AMP-PNP), a non-phosphorylating structural analogue of ATP, clearly stimulated insulin secretion and its effect was concentration-related. It was about 10 fold less active than ATP. The comparison of triphosphorylated derivatives from various purine nucleosides (ATP, GTP, ITP) or pyrimidine nucleosides (CTP and UTP) showed that only the purine derivatives had a strong insulin secretory effect with, in order of decreasing activity: ATP greater than GTP greater than ITP. These results show that certain structural features (purine basis and di- or triphosphate groups) are essential to elicit an insulin secretory effect.

Adenine Nucleotides↗
PubMed1978

[Endogenous hyperlactatemia and insulin secretion].

In the normal anesthetized dog, the endogenous hyperlactatemia induced either by intense muscular work or by a high dose of phenformin (20 mg/kg subtucaneously) is followed by an increase in the pancreaticoduodenal insulin output. A previous perfusion of sodium dichloroacetate (50 mg/kg. h) opposes the hyperlactatemia, and reduces or suppresses the increase in insulin output.

Animals↗
PubMed1977

[Lack of concordance in the effect of large doses of phenformin on insulin secretion and glycemia. Tentative analysis].

In the anesthetized dog normal or pretreated with phenformin (20 mg/kg per os) for 7 days, a subcutaneous injection of this biguanide (20 mg/kg) triggers a considerable hyperinsulinemia without concomitant hypoglycemia. The insulin secreted by these animals is biologically active on rat epididymal fat pads. On the other hand, epididymal fat pads of rats pretreated with phenformin display a lower response to insulin than that of non treated rats. The hypoglycemic effect of the same dose of insulin is less important in the normal dog after chronic pretreatment with phenformin.

Adipose Tissue↗
PubMed1977

[Actions of sodium dichloroacetate in combination with insulin on hyperlactatemia and hyperpyruvicemia induced in dogs by phenformin].

In the normal anesthetized dog the combination of insulin, whether of exogenous or endogenous origin, with sodium dichloroacetate provoke a rapid and important reduction of the hyperlactatemia and hyperpyruvicemia induced by the intraduodenal injection of high doses of phenformin. Furthermore this combination prevents the progressive and important lowering of the arterial pH provoked by phenformin.

Acetates↗
PubMed1976

[Non-saturable cooperative binding of tolbutamide to rat endocrine pancreas. Criteria of specificity].

The binding of 3H-tolbutamide to isolated islets, which shows a cooperative non-saturable pattern up to about 5 X 10(-5) M, was confirmed. Binding to exocrine pancreatic tissue shows much less cooperativity. Among congeners of tolbutamide, unlabelled carbutamide and chlorpropamide in isodynamic concentrations, as well as diazoxide in an exactly antagonistic amount, behave like tolbutamide 5 X 10(-5) M itselt by cancelling cooperativity when added to the labelled drug. Glipizide and glibenclamide do not.

Animals↗