EFFECT OF PDGF AND TGF-BETA ON THE RELEASE OF BIOGENIC-AMINES FROM INVERTEBRATE IMMUNOCYTES AND THEIR POSSIBLE ROLE IN THE STRESS-RESPONSE

PDGF-AB and TGF-beta 1 intervene in molluscan stress response, the for mer inhibiting and the latter inducing the release of norepinephrine a nd epinephrine from hemocytes, These amines are down-regulated even wh en TGF-beta 1 is added to hemolymph pre-incubated with PDGF-AB, The op posite behaviour is observed if the growth factors are reversed. The d opamine response is not affected in either case, even after the additi on of CRH or ACTH. After pre-incubation with PDGF-AB or TGF-beta 1 in the presence of CRH or ACTH, norepinephrine and epinephrine release fa lls, These findings suggest that when the interaction is between growt h factors, the order of combination is crucial, while in cases where t he interaction is between growth factors and other peptides, such as C RH and ACTH, the order is of no importance. (C) 1997 Federation of Eur opean Biochemical Societies.