PARTICULATE ANP-SENSITIVE GUANYLYL CYCLASE - INDUCTION IN CULTURED HUMAN PERIPHERAL CD3(-CELLS() MONONUCLEAR BLOOD)

There have been conflicting reports about the occurrence and/or activi ty of atrial natriuretic peptide (ANP) sensitive guanylyl cyclase in t he immune system. This study reports on ANP-sensitive guanylyl cyclase mRNA expression and guanylyl cyclase activity in human peripheral blo od mononuclear cells (PBMC). Reverse transcription polymerase chain re action (RT-PCR) shows that activated human PBMC of healthy blood donor s express functional active ANP-sensitive guanylyl cyclase after vitro culture, whereas freshly isolated PBMC show neither specific mRNA for particulate guanylyl cyclase nor ANP-sensitive activity of this enzym e. To define the subpopulation of PBMC expressing this enzyme, cultiva ted PBMC were subfractioned and analyzed by RT-PCR and in situ PCR. On ly CD3(+) PBMC showed mRNA for ANP-sensitive guanylyl cyclase. Inducti on of the guanylyl cyclase required coincubation with other cells, ind icating that a factor or factors secreted from cells other than CD3(+) cells induces this expression. In summary, ANP-sensitive guanylyl cyc lase is an inducible enzyme in human CD3(+) PBMC in contrast to other cells where it is considered to be constitutive.