The short prolactin receptor predominates in endothelial cells of micro- and macrovascular origin.
BACKGROUND
Controversial reports on prolactin receptors (PRL-R), the long and short form, on endothelial cells (EC) may be explained by the choice of EC derived from the micro- and macrovascular bed of either endocrine and non-endocrine organs.


METHODS
We studied here PRL-R expression in organs [bovine corpus luteum (CL), umbilical vein, aorta] and in organ-derived EC cultures.


RESULTS
In the intact CL, both PRL-R forms were present at mRNA and protein level throughout the oestrous cycle stages. The short form prevailed as protein. PRL-R-positive EC were noted by immunofluorescent staining in arterial blood vessels of CL septa, in the umbilical vein and the aorta. In EC cultures of micro- and macrovascular origin, transcripts of both PRL-R forms were shown; again the short-form protein prevailed. Blocking experiments with anti-prolactin (PRL) antibody led to a 60% decrease in cell growth. Treatment with PRL had no effect.


CONCLUSIONS
PRL-R expression in micro- and macrovascular EC is associated with the predominant short form.
Ricken
Albert M
AM
Department of Anatomy, University of Leipzig, Liebigstrasse 13, DE-04103 Leipzig, Germany. albert.ricken@medizin.uni-leipzig.de
Traenkner
Anja
A
Merkwitz
Claudia
C
Hummitzsch
Katja
K
Grosche
Jens
J
Spanel-Borowski
Katharina
K
D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D001011:Aorta / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D002417:Cattle; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D003338:Corpus Luteum / Q000098:blood supply*; D004305:Dose-Response Relationship, Drug; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism*; D030762:Estrous Cycle / Q000378:metabolism; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D006107:Granulosa Cells / Q000378:metabolism; D008833:Microcirculation / Q000378:metabolism; D011388:Prolactin / Q000276:immunology / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D011981:Receptors, Prolactin / Q000187:drug effects / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014471:Umbilical Veins / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*
D000906:Antibodies; D012333:RNA, Messenger; D011981:Receptors, Prolactin; D011388:Prolactin