HISTOCHEMICAL STUDIES ON FOLLICLES OF LANGERHANS OF AMMOCOETE LARVA OF LAMPETRA PLANERI (BLOCH)

Studies on the follicles of Langerhans of ammocoete larvae using differential staining methods and histochemical reactions have given results that are consistent with the view that the follicles contain a single type of glandular cell that secretes insulin or an insulin-like substance by a holosecretory mechanism. The cells are thus equivalent to β cells and there is no evidence for the presence of α-like cells or for the production of digestive enzymes by the follicles. Unlike the pancreas of adult Lampeira fluviatilis, there are very few dark" glandular cells within the follicles and these are thought to be a variant of the chief cells; the majority of "dark" cells are connective tissue cells. © 1969."