LOCALIZATION OF MESSENGER-RNA CODING FOR THE 3 SUBTYPES OF ATRIAL-NATRIURETIC-FACTOR (ANF) RECEPTORS IN RAT ANTERIOR-PITUITARY GLAND-CELLS

Atrial Natriuretic Factor (ANF) action is mediated by highly selective and specific receptors. Three subtypes have been characterized and cl oned: ANF receptor-A, -B and -C. These subtypes are all expressed in t he anterior pituitary of the rat. In the present study, the mRNA for e ach subtype was detected by in situ hybridization. The amounts of ANFR -A and -B mRNA were found to be similar, and to be twice that of ANFR- C mRNA, At the ultrastructural level, the three types of ANFR mRNA wer e expressed in three anterior pituitary cell types, namely lactotrophs , corticotrophs, and gonadotrophs, identified by their hormonal conten t. No signal was revealed in somatotrophs or thyrotrophs. The differen t forms of mRNA were similar in terms of subcellular localization: in the cytoplasmic matrix and the nuclear euchromatin. These data indicat e that the anterior pituitary is an important target tissue for ANF ac tion.