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INSULIN PRODUCES A BIPHASIC RESPONSE IN TETRAHYMENA THERMOPHILA BY STIMULATING CELL SURVIVAL AND ACTIVATING PROLIFERATION IN TWO SEPARATE CONCENTRATION INTERVALS
Author(s) -
CHRISTENSEN SØREN T.,
QUIE HELENE,
KEMP KÅRE,
RASMUSSEN LEIF
Publication year - 1996
Publication title -
cell biology international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.932
H-Index - 77
eISSN - 1095-8355
pISSN - 1065-6995
DOI - 10.1006/cbir.1996.0055
Subject(s) - tetrahymena , cell growth , hemin , cell , population , biology , cell culture , microbiology and biotechnology , chemistry , biochemistry , enzyme , medicine , heme , genetics , environmental health
Cells of Tetrahymena may produce autocrine signal molecules with effects on survival and proliferation. Here we have tested the effects of human recombinant and bovine insulin, and the B22–B30 fragment of bovine insulin over a wide range of concentrations (10 −5 –10 −18 m ) on cell survival and proliferation in a synthetic nutrient medium. The cells were grown in conical flasks at low initial cell densities (40 and 400cells/ml). Insulin prevented rapid cell death and/or promoted cell proliferation over two separate concentration ranges: down to nanomolar levels and again in the low pico‐ and femtomolar range. At an initial population density of 400cells/ml the cells multiplied at both concentration intervals. At 40 or fewer organisms/ml the cells multiplied in the high concentration interval, whereas in the low interval they survived for about four times longer than those in the control cultures. B22–B30 added to cultures of 40 initial cells/ml produced a stimulation of cell survival in the low pico‐ and high femtomolar range. In the presence of hemin (50n m ) cells at 400 initial organisms/ml multiplied at insulin concentrations down to about 3n m and again from 300a m to 10p m . In some cases, hemin plus insulin activated cell proliferation between the two concentration intervals as well. At 40cells/ml the cells not only survived but proliferated in the femtomolar range. Cells in cultures supplemented with both hemin and B22–B30 multiplied at the low concentration interval (from about 100f m to 10p m ).