Expression of neural cell adhesion molecules in the mouse anterior pituitary gland and pituitary tumor cells

Neural cell adhesion molecules (NCAMs) were immunocytochemically detected i n the pituitary glands of female ICR mice and in the pituitary tumor cell l ines (GH(3) cells and AtT-20 cells) using the antibody against mouse NCAM. Immunoreactive NCAMs (ir-NCAMs) were detected in the cell membranes of mous e pituitary cells, GH(3) cells and AtT-20 cells. Fifty four percent of ante rior pituitary cells, 58% of neurointermediate cells (cells of both posteri or and intermediate lobes), 13% of GH(3) cells and 43% of AtT-20 cells expr essed ir-NCAMs. Anterior pituitary cell types of NCAM-expressing cells were identified. Most of somatotrophs, gonadotrophs, and thyrotrophs showed NCA M-immunoreactivity, while parts of mammotrophs and corticotrophs did. The c ell-type-specific pattern of NCAM expression in the mouse pituitary may be closely associated with physiological roles of pituitary NCAMs. For clarify ing roles of pituitary NCAM, AtT-20 cells were treated with antisense oligo deoxynucleotide (ODN) which was complementary to the translation initiation site of NCAM mRNA, or with sense ODN which corresponded to the sense seque nce for 7 days. Antisense ODN treatment (100 nM) decreased the percentage o f NCAM-expressing cells, and surprisingly increased the cell number of AtT- 20 cells compared with sense ODN treatment and non-treatment. This result s uggests that NCAM is involved in the growth control of AtT-20 cells.