Association between elevated prolactin levels and circulating erythroid precursors in dialyzed patients.
The prolactin (PRL) receptor (R), a member of the cytokine hemopoietin receptor superfamily, has been shown to activate early differentiation steps along the erythroid pathway. In particular PRL, a product of bone marrow stroma, induces functional erythropoietin (EPO)-R on CD34+ hemopoietic progenitors. In this study, expression of EPO-R mRNA and responsiveness to EPO were assessed on enriched hemopoietic progenitor cells (HPC) from seven hyperprolactinemic and three normoprolactinemic patients and two normal subjects. Expression of EPO-R mRNA by semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) was found in HPC of four out of seven hyperprolactinemic patients but not in normoprolactinemic patients or normal donors. Development of EPO-dependent Colony Forming Unit-Erythroid (CFU-E) colonies in semi-solid medium was observed only in hyperprolactinemic patients (six out of seven). A much higher number of CFU-E colonies was observed in the four patients with a positive EPO-R message. We conclude from these data that abnormally high levels of PRL may increase the number of EPO-responsive hemopoietic precursors in vivo as they do in vitro. Since hyperprolactinemia associates in these patients with depressed EPO production, it may be regarded as a compensatory mechanism for the reduced availability of the hemopoietic factor.
Bellone
G
G
Department of Clinical Physiopathology, Nephrology Institute, and Department of Internal Medicine, University of Turin, 10126 Turin, Italy. bellone@golgi.molinette.unito.it
Rollino
C
C
Borsa
S
S
Ferrero
I
I
Martina
G
G
Carbone
A
A
Mareschi
K
K
Quarello
F
F
Piccoli
G
G
Emanuelli
G
G
Matera
L
L
D003114:Colony-Forming Units Assay; D015672:Erythroid Precursor Cells / Q000737:chemistry / Q000166:cytology*; D004921:Erythropoietin / Q000494:pharmacology; D005260:Female; D006801:Humans; D006966:Hyperprolactinemia / Q000097:blood* / Q000209:etiology; D008297:Male; D011388:Prolactin / Q000097:blood; D012333:RNA, Messenger / Q000097:blood; D017467:Receptors, Erythropoietin / Q000235:genetics; D006435:Renal Dialysis; D020133:Reverse Transcriptase Polymerase Chain Reaction
D012333:RNA, Messenger; D017467:Receptors, Erythropoietin; D004921:Erythropoietin; D011388:Prolactin