The formation of gastric ulcer in pregnant and nonpregnant rats in the light of data on the gestation dominant

Abstract

Vol. 51, No. 1, pp. 40-43, January, 1961 Original article submitted Januar}~ 18, 1960 Research in antenatal physiology and pathology, and study of the factors promoting fetal implantation and the formation of a full-value placenta, have permitted I. A. Arshavskii to prove his theory of the gestation domi' nant [1,2,3]. Constant afferent impulsation from the uterine interoceptors, which appears after fertilization of the ovicell and its implantation in the uterine mucosa [5], causes a focus of excitation to develop in the relevant nerve centers, which regulate the gonadotropic function of the hypophysis and the hormonal function of the corpus luteum. The associated inhibition attending the dominant focus of excitation allows one to understand the increase in the threshold of a pregnant organism in relation to a series of stimuli, especially pathogenic ones [1-4, 6, 9-14]. Sandweiss, Saltstein, and Farbman [14] cite statistical data on 70,310 women which indicate the absence or disappearance of incipient gastric and duodenal ulcer during pregnancy.The purpose of this work was to determine experimentally the possibility of gastric ulcer f6rmation in pregnant, as compared with nonpregnant rats. Ex~ r.i_m.en_ t al_~Me t h.o d s 9 n d R e s u 1 t_s Gastric ulcer was induced by a slightly modified version of K. A. Meshcherskaya's method [7,8]. In the first series of experiments, we first administered 8 mg/100 g caffeine into the gastric cavity on a hungry stomach and, 30 minutes later, we introduced arsenous acid administered in a dose of 1 rag/100 g in a 0.1% soda solution. In view of the poor solubility of arsenous acid, we added 100 mg sodium bicarbonate to 100 ml of the aqueous solution of the acid. We used a larger dose of caffeine in our experiments than specified by K. A. Meshcherskaya, because gastric ulcer does not form as easily in females as in males.The administration of caffeine and arsenous acid began one or two days after the rats were bred, and continued daily for 18-19 days. The rats were then sacrificed and the stomach and uterus opened.The first series of experiments were performed on 12 pregnant and 20 nonpregnant rats. A more or less expressed ulcerative process was discovered in the antral portion of the stomach of all the control (nonpregnant) animals: in six rats, this process was very slightly expressed, consisting of 1-2 small (1-1.5 mm in diameter) superficial ulcers; the formation of either a few or many ulcers was observed in four rats, but these ulcers were also small and not apparent from the external surface of the stomach; in eight of the rats, the small ulcers had begun to coalesce, and the process involved the deeper layers of the gastric wall (see figure, a). In these cases, the injury was apparent from the external aspect of the stomach, and adhesions to adjacent organs were often noted. In the last two nonpregnant rats in this series of experiments the injury was still greater, ending, in one 37