In circulation, prolactin exists in different forms: a monomeric form whose molecular weight (MW) is 22 kDA, a polymeric form, "big prolactin
" whose MW is 50-60 kDa, and a larger polymeric form, "macroprolactin," whose MW is greater than 100 kDa.
Friesen, "Characterization of big, big prolactin
in patients with hyperprolactinaemia," Clinical Endocrinology, vol.
Maintained fertility in a patient with hyperprolactinemia due to big, big prolactin. J Clin Endocrinol Metab.
Hyperprolactinemia due to big big prolactin is differently detected by commercially available immunoassays.
Big prolactin (60 kDa) and macroprolactin (150 kDa), which are present in serum in varying quantities, can cause apparent hyperprolactinemia, but they have no clinical importance because they exhibit little biological activity.
The polyethylene glycol (PEG) precipitation test is widely used to detect pseudohyperprolactinemia caused by big prolactin and/or macroprolactin.
Some forms of big big prolactin behave as complex of monomeric prolactin with an immunoglobulin G in patients with macroprolactinemia or prolactinoma.
(16.) Bjoro T, Johansen E, Frey HH, Turter A, Torjesen PA Different responses in little and big big prolactin to metoclopramide in subjects with hyperprolactinemia due to 150-170kDa (big big) prolactin.
The most common form in healthy persons and in most patients with hyperprolactinemia is a monomeric prolactin (Mr 23 000), but higher molecular mass forms such as big prolactin
(Mr 60 000) and big-big prolactin, or macroprolactin (Mr 150 000), sometimes predominate (1-4).
Maintained fertility in a patient with hyperprolactinaemia due to big, big prolactin
. J Clin Endocrinol Metab 1981;53:863-6.
Big big prolactin
, or macroprolactin, a prolactin-IgG complex with a molecular mass of -150 kDa according to reports, accounts for a small but variable percentage of total prolactin (2, 3).
Big, big prolactin
, or macroprolactin, has been described as the major immunoreactive prolactin species in the serum of several subjects before and during pregnancy (5, 9-11).