Ontogeny of human gastric lipase and pepsin activities

Abstract

Background/Aims: The developmental profile of human gastric lipase activity as well as the secretory capacity of the immature gastric mucosa are still unknown. The aims of this study were to establish tissue activity levels for lipase and pepsin in the various anatomical regions of the developing stomach and to assess whether lipase is secreted by the fetal gastric mucosa. Methods: Lipase and pepsin activities were assayed in 49 specimens of different gestational ages. Gastric explants were cultured in chemically defined medium for up to 5 days, and enzymic activities were measured in tissues and in the culture media. Results: Lipolytic activity was present in gastric tissues at 10–13 weeks and steadily increased for up to 20 weeks, whereas pepsin activity did not vary significantly over the periods of study. There was a clear decreasing gradient of lipase activity; the highest activity was in the fundic area, and the lowest activity was in the antrum. Quantitative pepsin activity did not vary over the gastric regions. During culture, total lipolytic and pepsin activity increased 3.8-fold, and both enzymes were secreted into the culture medium. Conclusions: Gastric lipase appears as early as 10–13 weeks. Adult distribution of the enzyme became established by 16 weeks' gestation. The secretion of lipase into the organ culture suggests that the gastric mucosa is the main source of lipolytic activity in gastric aspirates of premature infants.