The expression of insulin-like growth factors and their binding proteins in normal human lymphocytes
Nyman, T.; Pekonen, F.
Acta Endocrinologica 128(2): 168-172
1993
ISSN/ISBN: 0001-5598 PMID: 7680835 Document Number: 409769
The expression of insulin-like growth factors and their binding proteins in normal human peripheral lymphocytes was studied using the reverse transcriptase polymerase chain reaction method and Western ligand blotting. A quantitation of RT-PCR products was used to study the differences between normal and PHA stimulated lymphocytes. Normal freshly collected lymphocytes expressed mRNAs for both IGF-I receptor and IGF-II receptor but not expression of the corresponding growth factors was detectable. After stimulation with phytohemagglutinin the lymphocytes, however, expressed both IGF-I and IGF-II. Of the five IGFBPs examined, unstimulated lymphocytes expressed only IGFBP-2 and -3. Stimulated lymphocytes expressed IGFBP-4 and -5, in addition to IGFBP-2 and -3, whereas IGFBP-1 mRNA remained undetectable. The ligand blotting of lymphocyte conditioned media revealed production of 34K, 34K and 49K IGFBPs. The addition of estrogen, progesterone, IGF-I or growth hormone did not affect secretion of IGFBPs by lymphocytes.