Separation of acinar cells from lactating mammary gland using velocity sedimentation in an isokinetic gradient of Ficoll in tissue culture medium.

This report describes a procedure for the purification of acinar cells from the disaggregated lactating mammary gland of the rat. Following disaggregation of the 15 days postpartum mammary gland, two qualitatively different kinds of cells which exhibited alkaline phosphatase activity were identified. These two populations of cells were separated in a previously described isokinetic gradient of Ficoll in tissue culture medium using a centrifugal force of 55g for 14 minutes. The larger of these two types of cells was found in a well-defined subpopulation of mammary cells, 97.4 +/- 0.8% of which lacked demonstrable adenosine triphosphatase activity by light microscopy. Ultrastructurally, these cells were identified as being almost exclusively acinar cells. The potential significance of this method is discussed.