Fig. 7. The effects of bathing saline salicylate concentration on (A) fluid secretion rate, (B) secreted fluid salicylate concentration and (C) salicylate flux. Each point is the mean ±S.E.M. for 6-12 tubules. The inset in B shows the relationship between bathing saline salicylate concentration (mmol l^-1) and S/M, the ratio of salicylate concentration in the secreted fluid to that in the bathing medium. Curves in B and C were fitted to the Michaelis-Menten equation using nonlinear regression analysis. J_max refers top the maximum rate of transport and K_t to the concentration of salicylate required to produce 50% of the maximum flux.