SEALING OF THE FOLLICULAR LUMEN OF THE ANTERIOR-PITUITARY GLAND OF THE MALE-RAT

It is commonly accepted that follicular lumina of the adult rat anteri or pituitary gland are tightly sealed by junctional complexes, especia lly tight junctions, In this report, we describe the presence of folli cular lumina that are unsealed, Peroxidase (HRP) was used to study suc h structures and when injected through the femoral vein, was observed in association with a few follicular lumina, on their microvilli and a round the cilia of folliculo-stellate cells, The existence of peroxida se-positive follicles clearly shows that follicles of the hypophysis a re not always firmly sealed by tight junctions, The folliculo-stellate cells which faced the peroxidase-positive follicles displayed HRP dep osits which were membrane bound within their cytoplasm, These findings suggest an absorptive function for the folliculo-stellate cells.