Histochemical patterns in the proventriculus of the developing chick.

Abstract

AbstractThe proventriculus of White Leghorn chick embryos (stages 29–45) newly‐hatched chicks, and adult chickens were frozen, sectioned in a cryostat and treated histochemically to identify localizations of alkaline and acid phosphatase, adenosine triphosphatase, 5‐nucleotidase, nucleotide‐diphosphatase, non‐specific glycerophosphatase, glucose‐6‐phosphatase, non‐specific esterase and succinic dehydrogenase. Ribonucleic acid, proteins and acid mucopolysaccharides were identified in tissues fixed in FAA.Acid phosphatase, nucleotide‐diphosphatase, adenosine triphosphatase, succinic dehydrogenase, ribonucleic acid and proteins were present in the cells of the deep glands at all stages of development. Alkaline phosphatase and 5‐nucleotidase were found only in mesenchymal derivatives of the proventriculus. After the chick begins swallowing and digesting albumen, enzymatic activity increased and non‐specific esterase became very reactive.The surface epithelium is covered with a mucous coat. Ribonucleic acid, non‐specific esterase, acid phosphatase and nucleotide‐diphosphatase were localized in the basal portions of the epithelial cells. The functional significance of these different patterns is discussed.