| Popis: |
The effect of time and temperature on the intrinsic factor (IF) activity of acid in native human gastric juice was investigated using a standardized radioimmunoassay. The following observations were made on the loss of IF activity: at body temperature, the loss was very rapid over a period of 4 hr; at room temperature, the loss occurred at a much slower rate over a 7-day period; at + 1 C the loss was almost imperceptible over a week’s time; at − 20 C the deterioration was relatively rapid and led to an almost total loss in only 7 days; and at − 70 C, after an initial fall, no further deterioration occurred for the next 6 days. The initial loss at − 70 C could be minimized by rapid freezing and thawing of the gastric juice. When acid gastric juice was depepsinized, reacidified to its original pH value, and kept at body temperature, practically no loss of IF activity occurred over a 4-hr period. Thus the loss of IF at body temperature would seem to be caused by the peptic activity. Depepsinized, reacidified gastric juice stored at − 20 C showed only a minor loss of IF activity over several days. Therefore, the relatively rapid loss of IF activity when native acid gastric juice is stored at − 20 C would seem to be due mainly to the peptic activity. |
