The influence of embryonic testosterone treatment on bursal epithelial pinocytotic activity

Developing White Leghorn chicks were treated with testosterone propionate in ovo to effect a partial chemical bursectomy. After hatching, birds were administered carbon particles or horseradish peroxidase via the cloaca, and the transport of these tracers by the bursal epithelium was examined. Uptake of both tracers was inhibited in the treated when compared to untreated birds. The degree of development of interaction between bursal epithelium and underlying lymphoid tissue appeared to play a major role in determining ability of the epithelium to transport these tracers. Epithelium associated with follicles possessing medullary and cortical divisions was able to transport, while intraepithelial follicles or regions of the epithelium overlying diffuse lymphoid tissue did not transport either carbon or horseradish peroxidase. Bursal function in regional defense of the gut may depend on a local interaction of bursal epithelium with lymphoid, and perhaps other cell types.