Functional differentiation of the chick endocrine pancreas: Insulin storage and secretion

摘要

AbstractA radioimmunoassay for insulin, together with ultrastructural observations of the endocrine pancreas, were utilized to investigate developmental aspects of insulin storage and secretion in the chick embryo. Immunoreactive insulin was detected from the fifth embryonic day onwards, in both the pancreas and blood plasma. In addition, margination of well‐developed beta granules, and emiocytotic events were observed as early as the fifth embryonic day. The initial appearance of insulin, together with its subsequent developmental profile, correlate well with major metabolic events occurring in the embryonic chick, and are discussed in relation to a functionally responding system, the developing liver. The present data show that the chick endocrine pancreas has the potential for activity very early in development, and that insulin may be secreted at earlier embryonic stages than hitherto accepte