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Early Differentiation of Glucagon-Producing Cells in Embryonic Pancreas: A Possible Developmental Role for Glucagon
Leslie B. Rall, Raymond L. Pictet, Robert H. Williams and William J. Rutter
Proceedings of the National Academy of Sciences of the United States of America
Vol. 70, No. 12, Part I (Dec., 1973), pp. 3478-3482
Published by: National Academy of Sciences
Stable URL: http://www.jstor.org/stable/62870
Page Count: 5
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Glucagon and insulin are first detectable at the onset of rat pancreas organogenesis. Initially, the specific activity of glucagon is approximately 100-fold higher than that of insulin. At this early stage, endocrine storage granules, similar to α granules, are identifiable in electron micrographs. The granule characteristics, as well as the relative hormone levels, suggest that the early population of differentiated endocrine cells is in fact composed of glucagon-producing (A) cells. This high level of glucagon is present in the embryo much earlier than the metabolic processes thought to be controlled by this hormone. Moreover, glucagon-producing cells may be the first endocrine cells to differentiate. Other known endocrine products accumulate later, during the terminal stages of organogenesis. These observations suggest that glucagon may have a regulatory function in early embryogenesis.
Proceedings of the National Academy of Sciences of the United States of America © 1973 National Academy of Sciences