Todd W. Siegel

Synthesis and aldose reductase inhibitory activity of substituted 2(1H)-benzimidazolone- and oxindole-1-acetic acids

Abstract Potent in vitro inhibition of the enzyme aldose reductase (AR) was observed with several members of a series of 3-alkylated 2(1 H )-benzimidazolone-1-acetic acids, as well as with analogs from a structurally-related series of oxindole-1-acetic acids with 3-alkyl or 3-alkylidene substituents. Intrinsic activity against AR was, in general, greatest in compounds from the second series, especially with analogs which contain alkylidene side chains, with typical IC 50 values of ≤ 1 μM. However, in a streptozotocin-diabetic rat model, the best compounds from either series failed to prevent sorbitol accumulation in lens or sciatic nerve to the degree observed with AR inhibitors such as ponalrestat or zopolrestat.

The role of polyols in cerebral cell volume regulation in hypernatremic and hyponatremic states

To clarify the role of the sugar polyols, sorbitol and myo-inositol, in cerebral cell volume regulation, we studied the effect of sorbinil, an inhibitor of aldose and aldehyde reductase, on the size of the cerebral water compartments in rats with hypernatremia, hyponatremia and normonatremia. Experimental animals were pretreated with sorbinil, while comparison rats received the drug vehicle. Rats were made hypernatremic for 96 h by water deprivation and injections of hypertonic saline, while hyponatremia was provoked over 48 h by daily administration of 5% dextrose in water and vasopressin. Sorbinil treatment was continued throughout the hyper- and hyponatremic periods. The severity of hypernatremia and hyponatremia was similar in sorbinil-treated and corresponding vehicle-treated rats. Brain electrolyte content and the size of the cerebral intracellular water compartment were comparable in sorbinil-treated rats vs. controls under hypernatremic and hyponatremic conditions. Sorbinil reduced the cerebral sorbitol content by approximately 50%, irrespective of the serum Na+ concentration. In contrast, sorbinil had no effect on brain myo-inositol content which rose by 114% during chronic hypernatremia (P less than 0.0001). Cerebral levels of myo-inositol did not decline in hyponatremic rats. We conclude that (1) sorbitol is not an essential cerebral osmolyte; and (2) myo-inositol is involved in the maintenance of brain cell volume during severe hypernatremia but not under hyponatremic conditions.

Small molecule somatostatin receptor subtype-2 antagonists.

The first potent small molecule sst2 antagonists are reported. Altering known sst2 agonist molecules yielded compounds with high sst2 binding affinity and full antagonist activity. Compound 7a, for example, displaced somatostatin binding to the sst2 receptor with an IC(50)=2.9 nM and antagonized somatostatin action with an IC(50)=29nM.