The systemic effects of burn trauma impact on multiple systems of the body, affecting cell metabolism and function. This work examines the multivariate dependency of adenosine 3':5' cyclic monophosphate (cAMP) on three different forms of polyinositol phosphates in burn trauma. Burn injury was achieved by scalding predefined areas corresponding to 0, 20 and 50 per cent of the body surface area (BSA) on the dorsal and ventral surfaces of mice. At day 21, following twitch studies, cAMP levels in the gastrocnemius muscle were measured by 125I-labelled radioimmunoassay procedures. The levels of various polyinositol phosphates (inositol 1 phosphate (I1P), inositol 1,4 biphosphate (I1,4P2) and inositol 1,4,5 triphosphate (I1,4,5P3 or IP3)) were measured using myo-[2-3H]inositol. Through multivariate analysis, the dependency of cAMP was determined with respect to these three polyinositol forms as the independent factors. The contribution of each of these independent parameters was assigned to three-dimensional axes. Vector analysis determined the relationship of cAMP to each of the independent parameters in control, 20 per cent and 50 per cent burn groups. This vector analysis clearly illustrated the changing relationship that existed between the two signal transduction systems (sts) in control and burn groups. An understanding of these changing interrelationships may be useful in developing new means of treatment of a number of the systemic effects of burn trauma.