Apoptosis occurs independently of the release of interleukin-1 beta in the anterior pituitary of end-lactating rats

THE mechanism of Interleukin-1 beta (IL-1 beta) release remains unknown. Because of the absence of typical peptide signal on the precursor, IL-1 beta is not secreted through the classical pathway. The aim of this study was to determine whether IL-1 beta is released during apoptosis, as has been reported for activated macrophages. We chose anterior pituitary cells of end-lactating rats because of their capacity to produce IL-1 beta spontaneously and because this organ undergoes cellular degeneration. The combination of two techniques, reverse haemolytic plaque assay (RHPA) and terminal transferase dUTP nick end labelling (TUNEL), allowed us to observe simultaneously the release of IL-1 beta and apoptosis. Our results show that in these conditions apoptosis is not the mechanism of IL-1 beta release.