Normalization of lens protein kinase Cgamma in galactosemic dogs by a novel aldose reductase inhibitor.

The purpose of this study was to determine the effects of a novel aldose reductase inhibitor on lens protein kinase Cgamma (PKCgamma) levels in galactosemic dogs. Six-month old Beagles (12 total; 6 male and 6 female) were made galactosemic by feeding a diet of 40% galactose for 6 weeks. Three dogs per group were fed either control, normal diet, 40% galactose diet, 40% galactose diet with aldose reductase inhibitor at 100 mg/kg body weight per day given orally, or a control diet with aldose reductase inhibitor alone (1-H,7-H-5alpha,6,8,9-tetrahydro-1-oxopyran[4,3-beta](1) benzopyran, referred to herein as HAR-1). Lenses were removed and analyzed for toxicity by pathological examination. Lens polyol concentrations were determined by GC/MS. PKCgamma levels were determined by Western blot and by reverse transcriptase-polymerase chain reaction (RT-PCR). No toxicity was observed from the aldose reductase inhibitor when given at 100 mg/kg body weight per day for 6 weeks. Galactosemic dogs showed deterioration of lens cells. Deterioration included vacuole formation in the lens, cell lysis, and loss of cell nuclei. Galactosemic dogs given the HAR-1 appeared identical to control dogs. Polyol concentrations in the lenses were reduced by 50% in dogs fed the 40% galactose diet with the aldose reductase inhibitor, HAR-1. PKCgamma protein levels were reduced in the galactosemic dog lenses, but synthesis of PKCgamma was not affected, as measured by RT-PCR. The PKCgamma protein levels were similar to controls in dogs given the aldose reductase inhibitor, HAR-1, even when polyol concentrations remained 50% elevated above control levels. HAR-1, when given to control dogs, caused a reduction in the synthesis of PKCgamma mRNA but not in total PKCgamma protein levels. This study demonstrates the use of a novel aldose reductase inhibitor to control changes in PKCgamma in dog lens, a PKC that is known to control gap junction activity.

[Half-life of galactose in the blood plasma of lambs and sheep and the effect on various blood components after an i.v. galactose solution infusion]. / Untersuchungen über die halbwertszeit der Galaktose im Blutplasma bei Lämmern und Schafen sowie über die Beeinflussung verschiedener Blutbestandteile nach i.v. Infusion von Galaktoselösung.

Three lambs, aged between four and five weeks, and four sheep, aged one year, received infusions of galactose solutions (0.5 g galactose/kg body weight). The average half-life values were 28.7 minutes in the lambs and 59 minutes in the sheep. Average galactose concentrations, five minutes from mid-infusion, were 61 +/- 1.2 mg/100 ml of blood plasma in the lambs and 71 +/- 3.3 mg/100 ml in the sheep. The infusions caused statistically significant rises of glucose in the blood plasma of both lambs and sheep and an additional rise of fructose in the blood plasma of the sheep. In sheep galactose infusion resulted in rise of insulin in the blood plasma, within ten minutes from mid-infusion, the latter rise being statistically significant, from 53 +/- 26 microE/ml to 96 +/- 23.3 microE/ml. The lambs exhibited, as a result of the infusions, statistically significant rises of blood-borne lactate from 6.7 +/- 2.3 mg/100 ml to 16.7 +/- 1.2 mg/100 ml on average, within five minutes from mid-infusion.