Regulation of receptor concentration by homologous hormone. Effect of human growth hormone on its receptor in IM-9 lymphocytes.

摘要: When cultured human lymphocytes of the IM-9 line were exposed to growth hormone (hGH) at 37 degrees, washed for 2 hours, and incubated with 125I-hGH, binding 125I-hGH was reduced. The magnitude reduction in dependent on concentration present as well duration exposure. As little X 10(-11) M (0.5 ng/ml) had a discernible effect. Growth 10(-10) (5.0 ng/ml), which is low resting vivo occupies about 20% receptors steady state 30 produced 50% while 20 mg/ml, under conditions, an 80% loss receptors. Further increases further effect receptor loss. Thus, given (up preincubation degrees greater than occupancy by that conditions degrees. Analysis data indicated decrease due per cell without any change affinity or number. insulin these cells affected medium, hormone, but neither heterologous Exposure cycloheximide (0.1 mM) progressive smaller receptors, additive induced suggesting inhibited synthesis accelerated removed from concentrations restored rapidly; half 6 8 hours full complement 24 following removal hormone. If replaced cycloheximide, return delayed until removed. Thus restoration appeared require new proteins. These indicate very sensitive regulation also add support suggestion hormones general actively regulate their own