Cell blotting: a new approach to quantify hormone secretion from individual rat pituitary cells.

A new technique is described for quantification of PRL secretion from individual pituitary cells incubated 1-6 h on ImmobilonTM, a high protein binding capacity transfer membrane. After incubation, the membrane is processed according to procedures commonly used in Western blotting. Individual cells and their "zone of secretion" can be seen by light microscopy. Purified hormone, incubated and processed in a similar fashion, is used to generate a PRL standard curve. An OasysTM Image Analysis System is used to measure area and intensity of released hormone. PRL release ranged from 0.1-1.5 pg/cell, depending upon time of incubation and cell donor. Heterogeneity of hormone release from single cells was obvious.