[The heterogeneity of serum hPRL in a patient with a giant prolactinoma].

The heterogeneity of hPRL in the serum of a patient with a giant prolactinoma (hPRL 27 micrograms/ml) was studied employing gel chromatography, RIA and lymphoma cell bioassay. After gel filtration of serum sample on Sephadex G-100 (superfine) column, a few hPRL peaks were detected by RIA. Rechromatography of the second peak, which eluted between the void volume and the small third peak, revealed four hPRL peaks designated big-big hPRL, medium-big hPRL, big hPRL and little hPRL, with BA/RIA ratio 1.3 approximately 2.6, 0.8 approximately 1.2, 0.3 approximately 0.7 and 0.7 approximately 1.5, respectively. The molecular weight of medium-big hPRL was estimated as 80K approximately 90K daltons. Most of big-big, medium-big and big hPRL were converted to little hPRL after mercaptoethanol treatment. These data suggest that most of big-big, medium-big and big hPRL are aggregates of little hPRL.