Macroprolactinemia: Diagnostic, Clinical, and Pathogenic Significance
Electrophoresis of macroprolactin and Scatchard analysis of anti-PRL autoantibodies. (a) IgG was purified from the sera of the patients with macroprolactinemia (lanes 3–6) using a protein G column and run on SDS-PAGE under a nonreducing condition. PRL, which bound to the autoantibodies, was dissociated and immunostained at the same position as the 23 kDa human PRL standard (lane 1). The 23 kDa PRL band was not observed when IgG from a patient with prolactinoma was used (lane 2). The fuzzy bands migrating faster than PRL may be nonspecific staining of IgG light chain. (b) Scatchard analysis revealed low-affinity and high-capacity autoantibodies. (c) Displacement of 125I-hPRL-autoantibody complex by human PRL and other related peptides; hPRL: human PRL, pPRL: porcine PRL, bPRL: bovine PRL, rPRL:r at PRL, and hGH: human GH. Only hPRL could displace the binding of 125I-PRL with the autoantibodies. (Reproduced from [5, 15, 18]).