Human cytokines interleukin (IL)-3 and IL-6 affect the growth and insulin binding of the unicellular organism Tetrahymena.
Interleukin (IL)-3 and IL-6 significantly increase the growth rate of the unicellular organism, Tetrahymena. The effect elicited by IL-3 is long lasting as it was also detectable after 20 generations. Effect of IL-6 was detectable as long as the substance was present in the cell culture. Pretreatment with IL-3 did not enhance the proliferative response to subsequent IL-3 treatment, but the second exposure to IL-3 considerably depressed the active proliferation of Tetrahymena cells. However, a positive 'priming effect' elicited by IL-6 resulted in an increased growth rate following repeated IL-6 stimulation. Insulin binding to the plasma membrane of Tetrahymena was increased by IL-6 but not by IL-3 after 24 hours, and this enhancement appeared even after one hour incubation. If the cells were pretreated with insulin, IL-6 did not influence insulin binding, while an inhibition by IL-3 was observed. These results direct attention to the similarities of actions induced by IL-3 and IL-6 at different levels of phylogeny probably due to the presence of cytokine receptor-like structures on this unicellular organism.
Csaba
G
G
Department of Biology, Semmelweis University of Medicine, Budapest, Hungary.
Kovács
P
P
Falus
A
A
D000818:Animals; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007328:Insulin / Q000378:metabolism* / Q000494:pharmacology; D007377:Interleukin-3 / Q000494:pharmacology*; D015850:Interleukin-6 / Q000494:pharmacology*; D007700:Kinetics; D011972:Receptor, Insulin / Q000378:metabolism; D013769:Tetrahymena pyriformis / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D013997:Time Factors
D007328:Insulin; D007377:Interleukin-3; D015850:Interleukin-6; D011972:Receptor, Insulin