Modulation of human plasma fibronectin levels following exercise.

Elevated reticuloendothelial function and plasma fibronectin (PF) level correlate with reduced rat heat shock mortality. Procedures that enhance human PF level may offer some advantage in dealing with the adverse effects of environmental stress. Both short- (STE) and long- (LTE) term exercise programs were evaluated for their ability to increase male human PF. STE (1 week; N = 14) consisted of treadmill running (0% grade) in a hot environment (41 degrees C, 39% relative humidity). The LTE (12 weeks) program was studied in two parts (LTE-1, N = 10; LTE-2, N = 19), with each part divided into four subject groups. Two groups performed the same running program combined with either full-body or upper-body weight training. The other two groups participated in only the running or full-body weight training. STE and LTE-2 had a significantly (p less than 0.05) higher mean initial PF level than LTE-1. STE (337.1 +/- 22.8 vs. 372.5 +/- 17.0 micrograms.ml-1). LTE-1 (266.0 +/- 13.0 vs. 348.0 +/- 18.8 micrograms.ml-1), and LTE-2 (370.9 +/- 13.8 vs. 413.6 +/- 12.5 micrograms.ml-1) all resulted in significant (p less than 0.05) increases in PF after program completion. Therefore, with diverse exercise training programs, PF elevations were attained even when initial concentration was high or the program was of short or long duration. However, PF level was suppressed in LTE-2 at 4 (323.2 +/- 10.8 micrograms.ml(-1)) and 8 (339.6 +/- 15.0 micrograms.ml(-1)) weeks before elevations occurred at 12 weeks.(ABSTRACT TRUNCATED AT 250 WORDS)