ASSESSMENT OF PROLIFERATIVE ACTIVITY OF GLANDULAR CELLS IN HYPERFUNCTIONING PARATHYROID-GLAND USING FLOW CYTOMETRIC AND IMMUNOHISTOCHEMICALMETHODS

The proliferative activity of epithelial cells in hyperfunctioning par athyroid glands was estimated by flow cytometric and immunohistochemic al procedures. A total of 30 parathyroid glands, 29 hyperfunctioning g lands, and 1 normal gland were studied. The pathology of the 29 glands ,vas determined to be hyperplasia in 19 and adenoma in 10. The S-phase cell population was expressed in terms of the S-phase fraction (%SPF) calculated from the histogram by DNA flow cytometry and in terms of t he BrdU immunostaining labeling index (BrdU LI). Cells in all stages o f the cell cycle were studied by Ki-67 immunostaining and expressed in terms of the labeling index (Ki-67 LI). Both BrdU LI and Ki-67 LI val ues were low, ranging from 0% to 0.58% and from 0.21% to 2.62%, respec tively. The BrdU LIs were lower than the Ki-67 LIs, ranging from one-s ixth to one-twelfth of the values depending on the disease. There were significant correlations between the two indices (p < 0.001). The %SP F determined by Row cytometry was consistently higher than both the Br dU LI and the Ki-67 LI. This discrepancy cannot be explained precisely , and further improvements are required for the flow cytometric analys is of %SPF. The cell cycle study by BrdU and Ki-67 immonohistochemistr y suggested that the glandular cells of the hyperfunctioning parathyro id were characterized by low proliferative activity. No evidence of ra pid cell turnover rate assumed from the flow cytometric study could be observed in the hyperfunctioning parathyroid gland.