TRK NEUROTROPHIN RECEPTOR FAMILY IMMUNOREACTIVITY IN RAT AND HUMAN PITUITARY TISSUES

Several lines of evidence suggest that neurotrophins may be involved i n pituitary function. By immunocytochemical methods we analyzed the ce llular distribution of their functional receptors in the pituitary gla nd. In the rat pituitary gland Trks were differentially distributed. P unctate immunoreactivity for TrkA was observed within the neural lobe, whereas numerous nerve endings were immunostained for TrkB and TrkC i n the intermediate lobe. Endocrine cells of the intermediate lobe exhi bited intense immunoreactivity for the three Trks, whereas scattered e ndocrine cells of the anterior lobe displayed a robust immunostaining for TrkC. In addition, TrkA and TrkB immunoreactivity was located in n ormal and neoplastic endocrine cells from human pituitary adenomas. Th e differential distribution of Trks in the hypophysis suggests a poten tial role of different neurotrophins in pituitary functions. (C) 1998 Published by Elsevier Science Ireland Ltd.