[Evaluation of the effect of GHRH(1-44)NH2 on the secretion of interleukin-2 (IL-2) and soluble IL-2 receptor alpha (sIL-2Ralpha) from human peripheral blood mononuclear cells in vitro].
OBJECTIVE
The bidirectional communication between the neuroendocrine and the immune systems is now a subject of an intensive investigation. Somatoliberin (GHRH) is a hypothalamic hormone that enhances the synthesis and the release of growth hormone (GH) from the anterior pituitary cells. Few recent reports demonstrate also role of the neuropeptide in the regulation of the immune system function.


OBJECTIVE
The aim of the study was to examine the influence of GHRH on IL -2 as well as sIL -2Ralpha secretion from mitogen-stimulated peripheral blood mononuclear cells.


METHODS
Mononuclear cells (PBMC) were isolated from the peripheral blood of healthy adults according to the technique described by Böyum. Cells, cultured 24 hours at 37 degrees C in humidified atmosphere of 95% air and 5% CO2, were stimulated with phytohemaglutinin (PHA; 10 microg/ml), and then GHRH(1-44)NH2 at the final concentrations 10(-12), 10(-10), 10(-8) and 10(-6) M was added to appropriate wells. ELISA kits were used to measure IL-2 and sIL-2Ralpha concentrations in the supernatants of cultured cells. Comparisons between tested groups were made by U Mann-Whitney test. The differences were considered significant if p < 0.05.


RESULTS
GHRH stimulated the secretion of IL -2 into the supernatants acting significantly at the concentration of 10(-12) M (p < 0.001). Moreover, GHRH at concentrations 10(-10) M and 10(-8) M significantly increased the secretion of sIL-2Ralpha as well (p < 0.001). Strong positive correlation between tested GHRH concentrations and sIL-2Ralpha levels in the supernatants was demonstrated (r = 0.8664; p <0.001).


CONCLUSIONS
The results demonstrate the potential involvement of GHRH in the regulation of T lymphocytes secretory function.
Siejka
Agnieszka
A
Department of Endocrinology, Medical University of Łódź, Poland.
Stepień
Tomasz
T
Ławnicka
Hanna
H
Krupiński
Roman
R
Komorowski
Jan
J
Stepień
Henryk
H
D000328:Adult; D002478:Cells, Cultured; D004797:Enzyme-Linked Immunosorbent Assay; D013007:Growth Hormone-Releasing Hormone / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques; D007376:Interleukin-2 / Q000378:metabolism*; D053645:Interleukin-2 Receptor alpha Subunit; D007963:Leukocytes, Mononuclear / Q000378:metabolism*; D015375:Receptors, Interleukin-2 / Q000378:metabolism*; D018709:Statistics, Nonparametric
C508017:IL2RA protein, human; D007376:Interleukin-2; D053645:Interleukin-2 Receptor alpha Subunit; D015375:Receptors, Interleukin-2; D013007:Growth Hormone-Releasing Hormone