An spectrophotometric method which Erel and Neselioglu described was used to measure thiol/disulfide Homeostasis tests [14 (link)]. Disulfide bonds are reduced and combined with sodium borohydride, and then, thiol groups are formed. The reductant sodium borohydride which remained unused was consumed and removed with formaldehyde to prevent reducing DTNB (5.5’-dithiobis-(2-nitrobenzoic) acid), and after the reaction with DTNB, all of the thiol groups, including native and reduced thiol groups, were specified. If the natural thiols are subtracted from the total thiols, half of the difference represents the dynamic sulfur content. After native and total thiols were determined, disulfide/native thiol percent ratios (SS/SH), disulfide/total thiol percent ratios (SS/SH+SS), disulfide amounts, and native thiol/total thiol percent ratios (SH/SH+SS) were determined [15 (link)].