T. Watanabe et al., Changing distribution of islets in the developing human pancreas: A computer-assisted three-dimensional reconstruction study, PANCREAS, 18(4), 1999, pp. 349-354
Tissue specimens of nine normal human pancreata from fetuses, neonates, and
adults were subjected to serial sectioning and computer-assisted three-dim
ensional (3-D) reconstruction in an effort to study the growth of Langerhan
s' islets based on their distribution in the lobule and their relationship
with the ducts and arterioles. Also, islet volumes were obtained by 3-D mor
phometry. In 24-week-old fetuses, the islets were shown to be in direct con
tact with the ducts, whereas in the neonates, they gradually became separat
ed from the ducts, finally dispersing throughout the lobule in the adults.
This transition seemed to allow islet hormones to have physiological effect
s on the exocrine function of the acinar tissue, making the pancreas achiev
e the endocrine-exocrine correlation. However, half of the islets remained
next to the ducts even in the adult pancreata. With regard to the relations
hip between the islets and arterioles, "arteriolar" islets having an affere
nt arteriole accounted for similar to 20% in number, but their volume cumul
ated to similar to 70% of the total, comprising a greater part of the pancr
eatic endocrine gland.