Influence of atrial natriuretic peptide on thymocyte development in fetal thymic organ culture

The aim of the present study was to examine the effect of atrial natriuretic peptide (ANP) on T-cell development. The addition of ANP (10(-6)-10(-10) M, 7 days) to organ cultures of 14 day old fetal mouse thymuses (FTOC) resulted in a decreased cell yield (up to 65% of the amount in control cultures). Flow cytometric analysis revealed a decrease (up to 35%) in the percentage of the CD4+ CD8+ thymocytes accompanied by an increase (100%) of the CD4- CD8- cell population in FTOC incubated with ANP. Exposure of FTOC to ANP furthermore decreases the percentage of CD5 expressing cells and increases the mean size of thymocytes estimated by monitoring their forward scatter intensity (flow cytometry). Thus, ANP seems to affect maturation and differentiation of thymocytes.