PROLACTIN AND MACROPROLACTIN CONCENTRATIONS IN NORMAL SERA AFTER GEL-FILTRATION CHROMATOGRAPHY AND PEG IMMUNOPRECIPITATION
Measurement of the relative amounts of macroprolactin and monomeric prolactin in a subset of 10 randomly selected normal sera by gel-filtration chromatography revealed that macroprolactin makes up 2-9% of the total prolactin present.
In this case, however, should the protein A test result be negative, as clearly shown by the results obtained for one of our serum samples (PEGprecipitated PRL, 52%; protein A-precipitated PRL, 10%; high-molecular mass PRL by gel-filtration chromatography, 35%), the presence of high-molecular mass forms of PRL should be assessed by gel-filtration chromatography.
The recovery of PRL after precipitation with PEG from serum containing macroprolactin was lower and showed a quantitative relationship proportional to the percentage of macroprolactin present, as determined by gel-filtration chromatography (Fig.
All 11 samples with recoveries <50% from the Southend population were subjected to gel-filtration chromatography, which confirmed that macroprolactin was the predominant immunoreactive form of PRL in all of these samples.