Immunological characterization of two substance-P antisera with substance-P fragments and analogues [proceedings].

on the response of bone alkaline phosphatase to parathyrin. The results of a typical experiment showing percentage change in alkaline phosphatase activity compared with the hormone-free control are presented in Fig. 2(b). Tissue from 1-day-old animals was unresponsive to parathyrin, that from the 3-day-old animal showed decreased alkaline phosphatase activity and those from 5and 6-day-old animals showed an increase in alkaline phosphatase activity. All responses were maximal at 5-8min incubation time. In bone from 5-day-old rats a dose-dependent increase in enzyme activity was observed at 7min in the range 50fg/ml-50pg/ml (Fig. 2a). This study highlights the potential of quantitative cytochemistry for studying enzyme characteristics intracellularly without prior fractionation and purification. Because of the micro-quantities of tissue involved, it becomes possible to measurechanges in cellular enzyme activity caused by sub-picogram quantities of hormone. The present results of the effect of parathyrin on bone alkaline phosphatase introduce the prospect of a bioassay of greater sensitivity than the existing radioimmunoassay methods.