The effect of dexamethasone on the metabolism of the hormone regulators of carbohydrate metabolism in the postresuscitation period

Administration of dexamethasone (dexasone) to dogs against the background of dysfunction of the hypothalamic-pituitary-adrenal system (HPAS) developing in the first three days of the postresuscitation period causes diverse changes in secretion of hormones of the pancreas. At a relative normalization of HPAS functioning noted 7 days after resuscitation the drug was shown to decrease intensity of glycolysis and processes of lipid peroxidation.     

Mammalian glial cells in culture synthesize acetylcholine

In the present study we demonstrate that acetylcholine is synthesized by cultured mammalian glial cells identified by cell-type specific markers. Primary cultures of rat brain astrocytes or microglia contained 2.0 and 1.6 pmol acetylcholine/10⁶ cells on average respectively. Astrocyte cultures established from neonatal mouse brain contained even more acetylcholine (about 80 pmol acetylcholine/10⁶ cells). Primary cultures of rat brain astrocytes showed choline acetyltransferase (ChAT) enzyme activity of 3 nmol/mg protein/h; ChAT activity was blocked by 10 μM bromoacetylcholine. In conclusion, these data demonstrate the synthesis of the “neurotransmitter” acetylcholine in cultured glial cells, a finding which opens a new view upon the role of acetylcholine in mammalian brain.     

汉防己甲素对正常大鼠糖代谢作用的初步观察

本研究观察了汉防己甲素对正常大鼠血糖、血清胰岛素和血浆胰高血糖素水平的影响,结果表明:汉防己甲素(100mg/kg)腹腔注射后,血糖于0.5h明显升高(P<0.01),3h达高峰,7h恢复到空腹水平,24h血糖明显降低(P<0.05);血清胰岛素水平于给药后0.5h明显下降(P<0.05),7h降至更低水平(P<0.01),24h明显升高(P<0.01);血浆胰高血糖素水平于给药后0.5h至5h有逐渐增高的趋势。     

The effect of H2-receptor antagonists on antipyrine and pentobarbital metabolism in male and female rats

Pretreatment of male and female rats with cimetidine decreased the amount of 3-hydroxymethylantipyrine in the 24-hr urine, but urinary antipyrine and 4-hydroxyantipyrine were increased compared to that of the corresponding control rats. On the other hand, the amount of norantipyrine and the total amount of antipyrine and its metabolites were not changed by cimetidine, ranitidine and famotidine. These data suggest that ranitidine and famotidine have little effect on the microsomal mixed function oxidase system in male and female rats.     

The effect of aluminum on the metabolism of embryonic chick bone in tissue culture

The effect of aluminum (Al) on bone metabolism was assessed in organ cultures of embryonic chick bone. Al of 10^?4 M and above caused an inhibitory effect on mineralization without inhibiting matrix formation and a stimulative effect on demineralization without stimulating matrix degradation. Therefore, Al was shown to influence the mineral metabolism of bone.     

Effects of pentobarbital and veratridine on phosphatidylinositol and phosphatidate metabolism in rat parotid acinar cells

The metabolism of phosphatidylinositol and phosphatidate was studied in isolated rat parotid cells, incubated in a physiological buffer containing [32P]phosphate or [3H]glycerol. Carbamylcholine and epinephrine stimulated 32P incorporation into both of these phospholipids, causing their half-maximal effects at 2 and 0.8 microM respectively. The former concentration is much lower than that anticipated from binding studies. The Hill coefficients for carbamylcholine activation of 32P incorporation were 0.61 +/- 0.05 for phosphatidate and 0.64 +/- 0.05 for phosphatidylinositol. Pentobarbital (0.58 mM) inhibited the increased 32P incorporation caused by 5 microM carbamylcholine but not 100 microM carbamylcholine. Pentobarbital inhibited the incorporation of 3H equally in the presence and absence of epinephrine, indicating that the effect of pentobarbital on 32P incorporation is on turnover and not on de novo synthesis. Veratridine (200 microM) had no effect on phospholipid metabolism in the presence and absence of either carbamylcholine or epinephrine, which contrasts with our previous findings in synaptosomes [J.C. Miller and I. Leung, Biochem. J. 178, 9 (1979)].     

A study on the development of barbiturate tolerance and dependence in hamster glial cells in culture

Hamster astroblast glial cells (clone NN) in cell culture were exposed to from 1 × 10^?5 to 3 × 10^?3 M pentobarbital-Na and from 1 × 10^?5 to 2·5 × 10^?4 M morphine hydrochloride for various periods of time. Profound morphological changes were induced in a dose/time-related fashion by pentobarbital only. These consisted of growing of cellular expansions, parallel cellular arrangement and increased amounts of intracellular material. Exposure of the cells to morphine up to 6 weeks resulted in a dose-correlated decreased rate of proliferation, but no specific morphological alteration could be observed. The morphological changes induced in cultured glial cells by pentobarbital were accompanied by an increase in oxygen consumption (35–45%) as well as an increase in glucose uptake (90–110%). These effects were compared to those obtained with bromodeoxyuridine which affected glucose metabolism similarly. Furthermore, glial cells that had been treated for 4 weeks with the barbiturate were less sensitive to the depression of oxygen consumption by a challenging dose of pentobarbital-Na signifying the development of cellular tolerance. After having cultured the cells in barbiturate for 4, 9 or 14 weeks, normal medium was substituted. This resulted in severe degenerative changes and cell deaths as well as altered growth characteristics in the surviving cells, demonstrating some degree of cellular dependence on the barbiturate. In addition, cross-tolerance with ethyl alcohol was established since it could be substituted for the barbiturate without the occurence of degenerative changes.