An enzyme cytochemical study of the endocytic pathways in anterior pituitary cells of the mouse in vivo.

Abstract

The endocytic pathways within the five types of secretory cells in the mouse anterior pituitary gland have been stud- ied in vivo using the enzymatic tracer horseradish per- oxidase (HRP); cytochemical techniques for demonstra- tion of thiamine pyrophosphatase (TPPase) and acid hydrolase activities were employed to distinguish Golgi saccules from GERL Mice were injected intravenously with 30-90 mg HRP and killed 5 mm to 12 hr later. The anterior pituitaries from noninjected mice were prepared for mor- phological examination and demonstration of TPPase and acid hydrolase activities. In all preparations, comparisons were made among somatotrophs, mammotrophs gonado- trophs, thyrotrophs, and corticotrophs. Each cell type cx- hibited secretory granule formation predominantly from GERL. No significant differences in the localizations of TPPase or acid hydrolase activities were noted among the five cell types. TPPase activity appeared in one or two