Effect of the association time of in vivo bound prolactin on the [125I]prolactin receptor assays of female rat livers.
Significantly (P less than 0.01) reduced 125I-labeled ovine prolactin binding (mean, --22%), as a result of an ether anesthesia-reduced rise in serum prolactin, was observed in plasma membrane preparations of liver samples of female rats taken after 5 min of etherization when compared to samples taken from the same animals during the first minute of etherization. This reduction in assayable receptors occurred after 1 h but not 2 h of assay incubation time. Significantly (P less than 0.05) reduced 125I-labeled ovine prolactin binding (mean, --16%) was also observed in liver samples exposed to a 30-min ether-induced rise in serum prolactin when compared to liver samples taken during the first minute of etherization. In contrast, this reduction was apparent at assay incubation times of 1, 2 and 4 h but not at 10 h. These results suggest that serum prolactin can bind to prolactin receptors in vivo and partially block subsequent 125I-labeled ovine prolactin receptor assay. In addition, these data provide evidence that a complex time-dependent binding of prolactin may occur in the plasma of the female rat liver.
D000818:Animals; D001667:Binding, Competitive; D005260:Female; D008099:Liver / Q000378:metabolism*; D011388:Prolactin / Q000378:metabolism*; D011869:Radioligand Assay; D051381:Rats; D011956:Receptors, Cell Surface / Q000378:metabolism*; D012756:Sheep; D013045:Species Specificity
D011956:Receptors, Cell Surface; D011388:Prolactin