Synthesis of new 11 beta-substituted spirolactone derivatives. Relationship with affinity for mineralocorticoid and glucocorticoid receptors.

Various steroidal 17-spirolactones substituted in the 11 beta-position were synthesized to study the relationship between the nature of the 11 beta-arm and their affinity for cytosolic mineralocorticoid (MR) and glucocorticoid (GR) receptors prepared from adrenalectomized rabbit kidney or liver. One of them, the 11 beta-allenyl-3-oxo-19-nor-17-pregna-4,9-diene-21,17- carbolactone derivative, exhibited the same affinity for MR as aldosterone and a 5-fold higher affinity than mespirenone. Its affinity for GR was found to be relatively low. As suggested by molecular modeling, the marked differences in mineralocorticoid receptor binding affinity could be related to the structural features induced by this 11 beta-allenic substituent.

Synthesis of new 10 beta-propargylic and 11 beta-allenic steroidal spirolactones.

As part of continuing studies on the synthesis of new, biologically interesting 11 beta-substituted steroidal spirolactones, we describe here the competition between 10 beta-propargylation and 11 beta-allenylation. Grignard addition of allenyl magnesium bromide to an appropriate 5,10-epoxy-9(11)-olefin provides 10 beta-propargylation or 11 beta-allenylation. The role of the catalytic effect of copper chloride and of the solvent is evaluated. Confirmation of the structural assignments of these new 3,3-ethylenethioxy-10 beta-propargyl (or 11 beta-allenyl)-19-nor-17 alpha-pregna-4,9-diene-21,17-carbolactones is reported.

V1a-vasopressin specific receptors on human platelets: potentiation by ADP and epinephrine and evidence for homologous down-regulation.

Using very specific vasopressin (VP) analogues, the human platelet VP receptor was characterized as a V1a rather than a V1b receptor, on the basis of the effect of the analogues on shape-change and aggregation. The platelet VP binding sites appeared to be subject to homologous down-regulation by plasma VP, in view of the inverse correlation found between the maximal capacity of binding of tritiated VP to platelets and the immunoreactive VP concentration in poor platelet plasma from the same individual. Aggregating effect of VP on human platelets was potentiated by both ADP and epinephrine. In addition, VP was able to release serotonin from human platelets, but only at high concentration.

V1a vasopressin-induced accumulation of inositol trisphosphate in cultured rat aortic myocytes; modulation by protein kinase C.

Arginine vasopressin stimulated the accumulation of labeled inositol phosphate in cultured rat aortic myocytes prelabeled with tritiated myo-inositol. This accumulation was prevented by pretreating the myocytes with the phorbol ester PMA. The time-course and concentration-effect curves were similar for inositol phosphate formation in myocytes and contractile effects on isolated aorta. Vasopressin agonists also stimulated inositol phosphate formation, whereas vasopressin-induced response could be inhibited by V1a-specific antagonists. These results suggest that stimulation of inositol phosphate formation in myocytes is due to V1a receptor activation and could be modulated by protein-kinase-C-mediated mechanisms.

Nature and properties of human platelet vasopressin receptors.

The binding of 3H-labelled [8-arginine]vasopressin to human platelets or crude platelet membranes was examined. Both preparations specifically bound [8-arginine]vasopressin. The binding increased linearly with protein concentration, it was temperature- and time-dependent, saturable and could be reversed to a large extent by EDTA (10 mM). In this latter case, addition of an excess of MgCl2 (20 mM) restored the initial level of binding. Intact platelets and membranes derived from these platelets presented a single population of binding sites with a dissociation constant (Kd) of 1.3 +/- 0.2 and 1.8 +/- 0.3 nM and a maximal binding capacity of 142 +/- 48 and 270 +/- 17 fmol/mg of protein, respectively. The Kd values of various analogues correlated well with those determined on rat liver membrane V1 vasopressin receptors but not with those determined on rat kidney membrane V2 receptors.

[Sodium dichloracetate: its application to the therapeutics of experimental hyperiactatemia (author's transl)]. / Dichloroacetate de sodium: son application a la thérapeutique des hyperlactatémies expérimentales.

Different types of experimental hyperlactatemia and hyperpyruvicemia with or without lowering of blood pH were induced in anesthetized dogs. The initially studied experimental model was the hyperlactatemia and hyperpyruvicemia with lowering of blood pH induced by the intraduodenal administration of high doses of phenformin. Intravenous perfusion of sodium dichloroacetate (150 mg/kg infused during 20 minutes), which acts on the enzymatic complex of pyruvate dehydrogenase, reduced the hyperiactatemia and hyperpyruvicemia with or without acidosis provoked by phenformin injected intraduodenally (30 mg/kg), by intense muscular work, by hypoxia or by continous perfusion or adrenaline. Exogenous or endogenous insulin combined with sodium dichloracetate reduced the hyperlactatemia and hyperpyruvicemia as well as the changes in blood pH provoked by phenformin, more strongly than did sodium dichloroacetate alone. These findings have been confirmed in the conscious dog.

[Actions of sodium dichloroacetate in combination with insulin on hyperlactatemia and hyperpyruvicemia induced in dogs by phenformin]. / Actions du dichloroacétate de sodium associé à l'insuline sur l'hyperlactatémie et l'hyperpyruvicémie provoquées chez le chien par la phenformine.

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.

[Cure of experimental hyperlactatemia and lactic acidosis by sodium dichloroacetate]. / Correction de l'hyperlactatémie et de l'acidose lactique expérimentales par le dichloroacétate de sodium

Sodium dichloroacetate prevents and fights against the severe hyperlactatemia and lactic acidosis induced by phenformin, intense muscular work, hypoxia and by adrenalin perfusion. The beneficent effects of sodium dichloroacetate and insulin are additive.

[Correction of experimental hyperlactatemia and lactic acidosis by sodium dischloroacetate]. / Correction de l'hyperlactatémie et de l'acidose lactique expérimentales par le dichloroacétate de sodium

Sodium dichloroacetate prevents and fights against the severe hyperlactatemia and lactic acidosis induced by phenformin, intense muscular work, hypoxia and by adrenalin perfusion. The beneficent effects of sodium dichloroacetate and insulin are additive.

[Effect of sodium dichloroacetate on hyperlactatemia and hyperpyruvicemia induced by phenformin in the dog]. / Effet du dichloroacétate de sodium sur l'hyperlactatémie et l'hyperpyruvicémie provoquées par la phenformine chez le chien

In the normal anesthetized dog a continuous perfusion of sodium dichloroacetate (30 mg/kg.h) prevents the increase in blood lactates and pyruvates as well as the lowering of the arterial pH induced by the intraduodenal administration of phenformin (30 mg/kg). Furthermore a perfusion of sodium dichloroacetate (7.5 mg/kg.mn) during 20 minutes, three hours after the administration of phenformin, tends to improve the utilization of blood lactates and pyruvates.

[Effect of cocarboxylase on hyperlactatemia and hyperpyruvicemia induced by phenformin in dogs]. / Effet de la cocarboxylase sur l'hyperlactatémie et l'hyperpyruvicémie provoquées par la phenformine chez le chien

In the normal anesthetized dog, a cocarboxylase perfusion considerably reduced the increase in blood lactate and pyruvate levels provoked by the intraduodenal injection of phenformin (30 mg/kg); furthermore it seems to counteract the increase of the lactates/pyruvates ratio and opposes the fall in blood pH.