Using 'off the shelf', computer programs to mine additional insights from published data: diurnal variation in potency of ACTH stimulation of cortisol secretion revealed

We describe the use of available computer programs to mine additional insig hts from published data. Graphs from four studies of ACTH and cortisol plas ma levels collected throughout the 24 h day in humans were scanned into dig ital form and the data points extracted. To investigate the magnitude of AC TH stimulation of cortisol secretion across the 24 h, Monte Carlo methods w ere used to fit the parameters of a computer model of the ACTH-adrenal axis to the extracted data. ACTH was found to have a greater effect on cortisol secretion during the peaks of the cycle than at the nadir. This finding co uld not be explained by previously published dose response curves of ACTH e ffect. This implies that other modulators influence the effect of ACTH on t he adrenal. This study also demonstrates how available computer programs ca n be used to examine models of physiologic regulation using data already av ailable in the literature. (C) 1999 Elsevier Science Ireland Ltd. All right s reserved.