Flow cytometric analysis and sorting of live male rat anterior pituitary cell types by forward angle and perpendicular light scatter.

Light scatter patterns produced by living cells in the flow cytometer are known to provide useful information with regard to their size and internal structure. The purpose of this study was to determine if light scatter signals produced by live male rat anterior pituitary cells could be used as markers to aid in the identification and separation of different hormone-containing cell types. The typical light scatter pattern (4 X 10(5) cells/sample X 15 min) had three ridges in the forward angle light scatter (FALS) perpendicular light scatter (PLS) bivariate cell distribution. FALS signals could be correlated with the size of different cell types and PLS signals with their content of cytoplasmic secretory granules. Agranular cells dominated the low PLS ridge while moderately granulated PRL cells and heavily granulated GH cells dominated the medium and high PLS ridges, respectively. These light scatter patterns were reproducible both within and between different cell suspensions. Inclusion of dopamine in the pituitary gland dissociation medium, a treatment known to increase intracellular PRL contents of mammotrophs, increased the intensity of the PLS signals of a large population of cells, presumably PRL cells. Pituitary cells prepared from different aged male rats also showed changes in light scatter. Cell sorting on the basis of FALS-PLS signals established the relationship between cell type and light scatter pattern.