Differences in liver nucleic acid patterns following hypophysectomy and a restoration toward normal by growth hormone treatment have been described by Geschwind, et al. (1950), Di Stefano, et al. (1952), and Bergerard and Tuchmann-Duplessis (1953). Di Stefano, et al. (1952), using cytophotometric methods as well as standard chemical techniques, were able to demonstrate that the liver cells of hypophysectomized rats contained less ribose nucleic acid (RNA) and protein than did those of intact controls. After treating hypophysectomized rats for seven days with a purified growth hormone preparation, the hver cells contained the same amount of protein as that found in the cells of intact controls. Nuclear and cytoplasmic volume paralleled the protein pattern. Under these conditions both nuclear and cytoplasmic RNA values were found to be higher than those seen in the controls. The alterations in cellular proteins and nucleic acids described above affords an opportunity to study possible relationships between these substances in the mammalian cell.

THE administration of purified pituitary growth hormone to either hypophysectomized or intact rats results in nitrogen retention and increased protein synthesis. However, the mechanisms involved are unknown. Recently, several investigators have described high concentrations of ribosenucleic acid (RNA) in cells actively engaged in protein synthesis (Brachet, 1950; Caspersson, 1950; Davidson, 1950) and increases of this nucleic acid in cells which have an accelerated rate of protein synthesis. This constitutes circumstantial evidence that the concentration of RNA in cells may be related to their protein anabolic activity. That growth hormone may exert its protein anabolic effect by a mechanism involving nucleic acid metabolism is suggested by at least two recent studies. Geschwind et al. (1950) have shown that hypophysectomy results in a lowering of the RNA concentration of rat liver, and that growth hormone treatment of hypophysectomized rats restores the liver RNA concentration to normal. Further, Kalter et al. (1950) have described enhancement of the growth rate of influenza virus in mice treated with purified pituitary growth hormone.

Administration of alloxan to white rats causes an increase in the DNA and the histone of liver nuclei. Direct measurements indicate no change in cytoplasmic RNA, but, indirect evidence suggests an increase in nuclear RNA.

1. The administration by stomach tube of equivalent amounts of three antihistamine drugs (Phenoxadrine, Benadryl, Pyribenzamine) does not cause a significant change in adrenal ascorbic acid concentration in the rat. 2. The intraperitoneal injection of histamine phosphate (10 mgm./kgm. of body weight) lowers the adrenal ascorbic acid concentration from 400 mgm./100 gm. of tissue to 277 mgm./100 gm. of tissue. 3. Histamine injection one hour after pretreatment with Phenoxadrine or Pyribenzamine results in a smaller fall in adrenal ascorbic acid than that in control animals. Pretreatment with Benadryl, however, does not prevent or modify the adrenal ascorbic acid response to histamine. 4. Under the conditions of these experiments Benadryl administration was followed consistently by a small but significant hyperglycemia while Phenoxadrine and Pyribenzamine did not elicit this response. 5. Pretreatment with an antihistamine drug did not prevent or modify the adrenal ascorbic acid response to the stress of intraperitoneal carbon tetrachloride administration. 6. A description is given of the hypotensive effect of intraperitoneally administered histamine and the modification of this effect by antihistamine drugs in the rat.