Morphometric and allometric study of the mouse exocrine pancreas growth during the postnatal life

Postnatal mouse pancreas growth was submitted to allometric analysis by the Wald nonparametric method, modified by Bartlett. The body and gland mass were obtained and the total cell number and the absolute compartmental volumes of acini, ducts and stroma were evaluated by morphometric methods. The allometric coefficients were calculated for the growths between the following parameters: a) pancreatic mass and body mass; b) acinar compartmental volume and body mass; c) ductal compartmental volume and body mass; d) stroma volume and body mass; e) total cell number and body mass; and f) acinar volume and stroma volume. The results of these analysis showed that the pancreatic mass, total cell number and stroma volume exhibited statistically significant allometric growths with a monophasic pattern and allometric coefficients of 1.56, 1.27 and 1.29, respectively, for the periods of 2 to 70, 2 to 28 and 2 to 70 days of age; while the growth of compartmental acinar volume in relation to body mass and compartmental stroma volume was biphasic. In the first case, the 1st phase occurred between 2 to 14 days (K = 1.09) and the 2nd phase between 14 to 70 days (K = 1.44) and in the second case, the 1st and 2nd phases occurred, respectively, between 2 to 28 days (K = 1.31) and 28 to 70 days (K = 0.79) of age. The growth of ductal volume in relation to body mass was also biphasic with a 1st phase between 2 to 14 days (K = 0.88) and a 2nd phase between 14 to 70 days (K = 1.07). These results permitted us to conclude that the growth of the mouse pancreas is allometrically associated with the growth of body mass.