Analysis of the secretion from single anterior pituitary cells by cell immunoblot assay.

The CIBA is very useful in quantifying hormone secretion from single endocrine cells. Variations of this assay can extend its power for evaluating the proportion of hormone-secreting cells in a cell population, determining the responsiveness of individual cells to a particular secretagogue and identifying multihormones that are simultaneously secreted by the same cells. By using the CIBA and its variations, mammotrophs were shown to be heterogeneous with respect to the responsiveness to DA and TRH and cosecretion of PRL and GH. Furthermore, the fact that SP secretion from pituitary cells was increased by thyroidectomy via an increase in the number of SP-secreting cells indicates the possibility that the CIBA can clarify mechanisms underlying changes in hormone secretion and intercellular signaling at the cellular basis.