High alkaline phosphatase activity in isoproterenol stimulated fibroblast cultures from patients with numerically unbalanced chromosomal aberrations.

Treatment of cultured fibroblasts from patients with unbalanced chromosomal aberrations with a mixture of isoproterenol, theophylline and ascorbic acid resulted after 48 hours in an at least three-fold increase of alkaline phosphatase activity on a per cell basis, whereas cells from normal healthy individuals did not show this dramatic response. Cells were studied from patients with trisomy 21 (14 cases), trisomy 18 (3 cases), trisomy 13 (1 case), pentasomy X (1 case), Turner syndrome (2 cases), and Klinefelter syndrome (1 case), and no exception was noted. The mechanism of this phenomenon is not clear, but it is speculated that increased cyclic-AMP levels caused by the action of isoproterenol on adenylcyclase may account for excessive reactions of unbalanced cells as compared to normal cells. This simple biochemical diagnostic procedure might become useful in screening programs for unbalanced chromosomal abberations.