PROLAKTIN-KONZENTRATIONEN IM MENSCHLICHEN PLASMA WÄHREND SCHWANGERSCHAFT UND WOCHENBETT

ABSTRACT Plasma prolactin concentrations were measured during pregnancy by the local pigeon crop test. The levels were between 0 and 3 IU/100 ml plasma up to the 24th week of gestation. There was no elevation of the prolactin plasma levels between the 24th week and the 40th of gestation. The prolactin concentration during the second half of pregnancy ranged between 2 and 7 IU/100 ml plasma. It was suggested that the biological prolactin activity measured during pregnancy is not identical either with the human growth hormone or with the placental lactogen hormone. A calculation comparing the levels of HCG and placental lactogen excluded in the authors' opinion the identity of those hormones with the biological prolactin activity. The prolactin concentration decreased in the plasma during labour and increased in the following 4 days post partum. After this post partum peak the plasma prolactin concentration fell to a value below 1 IU/100 ml plasma. In the late puerperium – 4 to 6 weeks after delivery – it was possible to measure plasma prolactin levels in women with a normal lactation around a mean value of only 1 IU/100 ml. Obviously prolactin does not play an important role for the maintenance of lactation whereas the striking rise of the plasma prolactin concentration in the following 4 days post partum could mean a possible function for the initiation of lactation.