Effect of zenarestat, an aldose reductase inhibitor, on endoneurial blood flow in experimental diabetic neuropathy of rat.

The effects of zenarestat, an aldose reductase inhibitor, on endoneurial blood flow (NBF) were explored in streptozotocin-induced diabetic rats. Rats were maintained on a diet of containing 0.09% zenarestat for 8 weeks, then NBF in the sciatic nerve was measured using microelectrode hydrogen polarography. NBF in the diabetic control rats was significantly lower than values in age-matched control rats, however, NBF was not significantly altered in diabetic rats treated with zenarestat. Direct application of nitric oxide synthase inhibitor, NG-nitro-L-arginine, did not affect NBF in diabetic control rats, whereas this application significantly reduced NBF both in age-matched control and zenarestat treated diabetic rats. Considerable levels of zenarestat were confirmed in the sciatic nerve in the drug treated rats. These data suggest that aldose reductase, such as zenarestat, might restore or prevent the alteration of endoneurial blood flow resulting from an impairment of nitric oxide function.

Fine structure of rat liver, adrenal, testis and seminal vesicle in experimental emaciation.

Experimentally emaciated male rats were produced by a bilateral electrical destruction of a part of hypothalamus. In a typical case, when the animals were fixed by perfusion, dissected, and organs weighted, the body weight became 1/2 of the control in 10 weeks. The weight of the viscera (including the subserous fat) was more decreased in comparison with the controls than the weight of the body wall (including extremities and the subcutaneous fat). The weight of the liver became 1/3, the adrenal 1/4, the testis 1/6 and the seminal vesicle 1/19 of the control. Light and electron microscopic examinations showed atrophy and fatty degeneration in the liver, atrophy of the zona reticularis in the adrenal, failure of spermatogenesis, especially at its spermiogenetic stage, in the testis, and an apoptosis in glandular epithelial cells of the seminal vesicle. Two weeks after partial hypothalamus destruction, the weight of the body wall was more decreased in comparison with the controls than the weight of the viscera. Possible pathophysiological mechanisms are discussed. An experimental model of electron microscopical research of apoptosis are presented.