BASEMENT-MEMBRANE PROTEINS, APOLIPOPROTEIN-E AND GLYCOSAMINOGLYCANS IN PITUITARY-ADENOMAS AND THEIR CORRELATION TO AMYLOID

The aim of the study was to confirm earlier reports of the association of amyloid deposits in growth hormone (GH)-producing adenomas of the pituitary and the presence of glycosaminoglycans, basement membrane pr oteins and apolipoprotein E (apo E). Serial sections from 17 amyloidot ic and 11 nonamyloidotic, sparsely granulated, GH-producing adenomas o btained from patients presenting with acromegaly were stained with Con go red and Alcian blue, and also with antisera directed against fibron ectin, collagen IV, laminin and apo E. Glycosaminoglycans were found i n capillaries of every adenoma and were also related spatially to amyl oid deposits. Immunostaining of both nonamyloidotic and amyloidotic ad enomas demonstrated the presence of fibronectin, collagen IV and lamin in in the basement membranes of surrounding nonadenomatous tissue and tumour vessels. In approximately half the amyloidotic adenomas, each b asement membrane protein presented with a distinct spatial relationshi p to amyloid deposits. Apo E was found in 88% of the amyloidotic adeno mas within the amyloid deposits, and in six cases intracellular immuno staining was also evident in folliculo-stellate cells. The results are consistent with the presence of glycosaminoglycans, basement membrane proteins and apo E in the amyloid deposits of pituitary adenomas.