Abstract
The bovine hypophysis serves as an excellent model for studying salient gross anatomical and microscopic features relative to the activity of the intermediate lobe.
A potential space between the anterior and intermediate lobe is converted into an intraglandular lumen during the cyclic behavior of the intermediate lobe. The cyclic behavior of the lobe is exhibited by 3 phases of cellular activity: 1) resting, 2) desquamation and autolysis, 3) regeneration. During the second phase, the marginal zone of intermediate lobe cells increase in size from 0.3μ to 10μ in diameter. As these cells autolyze, they break away from the deep zone thus giving rise to an intraglandular lumen. Within the lumen, the desquamated cells undergo further autolysis resulting in the formation of colloid, the breakdown product of marginal intermediate lobe cells.
As the intermediate lobe re-establishes itself by direct division of its remaining cells, the colloid is expelled from the intraglandular lumen into the venous cavernous sinuses by way of well defined capsular clefts.
