Paired augmented histamine tests using 40 microgram 60 microgram histamine acid phosphate (HAP) per kg body weight were conducted on each of 57 Asian subjects. The mean peak acid output (PAO) for the total series to the two different doses of HAP was 22.3 mEq/hr and 23.3 mEq/hr respectively and the difference was not statistically significant according to the paired t test. There were similarly no significant difference in PAO to the two doses of HAP in the following groups of subjects: 26 Chinese, 17 Indians, 14 Malays; 24 subjects with duodenal ulcer, 16 controls; 28 subjects with body weight below 50 kg, 19 between 50-60 kg and 10 exceeding 60 kg. These findings differ from earlier reports that for maximal gastric secretion Asians required a higher dosage of histamine compared with Caucasian subjects.
Basal and pentagastrin stimulated acid output was measured in 80 normal and 179 duodenal ulcer subjects of Chinese, Indian and Malay origin. Basal and maximally stimulated acid output was significantly higher in duodenal ulcer patients compared with normal subjects. There was however considerable overlap and less than one in four duodenal ulcer patients were hypersecretors. The acid output (and hence the parietal cell mass) was lower than in Caucasian subjects and this was possibly related to weight differences. The acid output did not differ significantly in the Chinese, Indian and Malay subjects, suggesting that parietal cell mass in the three racial groups is closely similar. The difference in frequency of duodenal ulcer disease in the three racial groups is thus not related to gastric secretory capacity.