Immunoglobulin IgG detected by ELISA in bovine pituitary intraglandular colloid, a non-vascular holocrine secretion of intermediate lobe cells.

The purpose of this study was to determine the presence of immunoglobulin G in bovine pituitary intraglandular colloid (IGC). Intraglandular colloid, housed in the intraglandular lumen (residual lumen), is the holocrine secretion of the marginal layers of intermediate lobe (IL) cells. Immunoglobulin G was detected and quantitated in bovine IGC using an Enzyme Linked Immunosorbent Assay (ELISA). This study establishes the presence of immunoglobulin G in the intraglandular colloid at levels that are of the order of 10 micrograms per mg of colloid. The existence of this molecule in material scrupulously prepared to exclude the possibility of serum contamination in this normally avascular compartment is a unique phenomenon.