Protein content, dry mass and chemical composition of individual mast cells related to body growth.

Recently developed quantitative microscopical techniques were used to study relations between body growth and protein content as well as dry mass of individual mast cells. Since previous studies had shown an age-related increase of mast cell content of 5-hydroxytryptamine (5-HT) and heparin, these mast cell components were also included in the present study. The cells were obtained from the peritoneal cavity of rats aged 44--269 days (body weights 189--610 g). All studied mast cell parameters showed an increase that was related to the growth of the animals. The dry mass increased 60%, protein 50%, heparin 50% but 5-HT increased as much as 260% during the studied growth period. There was a mutual and linear correlation between all studied mast cell parameters. Population studies, based on large scale measurements of individual mast cells from young and adult rats, were made. These studies showed that histograms of 5-HT content, protein content and dry mass of individual mast cells were skewed with a tail towards higher values and approximately lognormal. On the other hand, the frequency distribution of heparin content of individual mast cells was approximately normal.