To evaluate the potential use of the SPR as a biomonitoring tool, a stepwise plan was utilized that proceeded through various physical and chemical laboratory exposures and culminated with a field validation study. The goals of the laboratory exposures were threefold: 1) determine the time required for induction of the SPR; 2) determine the dose-responsiveness of the SPR; and 3) compare the increased syntheses and accumulations of stress proteins to classical toxicological endpoints (i.e. percent mortality, LC50, LC1, etc).Brain, gill, and striated muscle tissues of fathead minnows (Pimephales promelas) exposed to heat shock, sodium arsenite, sodium chromate, lindane, and diazinon elicited tissue and stressor specific translation patterns. Increased syntheses and accumulations of several proteins were found to be concentration dependent at environmentally relevant levels. All tissues under all exposure regimes elicited a 70 kD protein. This protein was determined to be indicative of general stress. Two proteins of 20 and 30 kD were only found in fish exposed to arsenite and chromate. Thus, these two proteins may serve as metal indicators.Gill of fathead minnows exposed in situ to a toxicity gradient in Soldier Creek, Midwest City, Oklahoma were found to accumulate stress protein 70 in a manner that reflected in stream fish species richness.The results of this research demonstrates that the stress protein response has potential as a rapid and environmentally relevant biomonitoring method for assessing both general and stressor specific perturbations in fish. Figure 3. A. A fluorogram of striated muscle protein from fathead minnows exposed to 34 0 C for 1-hour and then transferred to 25 0 C for 11 hours and sampled at 0, 1, 3, 7, and 11 hours post heat shock exposure. Molecular weight markers of 97, 66, 42, 31, 21, and 14 kD, respectively, are designated on the left. Arrows on the right denote heat shock proteins of 90, 78 and 70 kD. B. Median intensities of 90, 78, and 70 kD proteins in fluorograms from replicate samples (n = 3) of experiment described in A. Intensities were determined densito metrically and are presented as arbitrary units (see Materials and methods Unfortunately, their clinical use is lacking (Bouk, 1984). Clinical use implies that the method has been validated by extensive testing-both to identify the biological significance of the parameter and the limitations in applying the test to the species in question.Much of the early biomarker work involved measurements of blood and enzyme activity as well as biochemical composition of blood and tissues (Mazeud and Mazeud, 1981;Neff, 1985), methods primarily transplanted from human and veterinary medicine. Unfortunately, many of these parameters were not applicable across phyla and measured secondary effects, symptoms, of an underlying problem rather than highly conserved parameters intimately involved in the protection and/or defense of the cell. Thus, biomarkers that correspond to events that are coupled to cellular protection and defens...