Figure 4
Couplet Cells with membrane TCC receptors . (a) A couplet of cells ( a C and i C) with each producing a Trefone and each having a receptor (R) to bind the Trefone produced by the other cell. This is as in Figure 3 but with a TCC receptor ( TCC R) on each cell. (b) A couplet of cells with the a-Cell producing the “a” Trefone, IGF-I, the i-Cell producing the “i” Trefone, an IGFBP, and each having a receptor to bind the Trefone produced by the other cell. This is as in Figure 3 but with a receptor for an IGF-I:IGFBP complex on each cell.