Stimulating action of human serum on the incorporation of tritiated thymidine in human lymphocytes activated by lectins: demonstration of the GH-dependency and its limitations

Using thymidine uptake by activated human lymphocytes to measure the growth-stimulating activity of human serum, the authors demonstrate that thymidine activity was significantly correlated (p less than 0.001) with GH levels. r = 0.729 when GH values are below 3.5 ng/ml, r = 0.509 when GH values are below 8 ng/ml and r = 0.337 for all of the patients. Low levels of GH are sufficient for the generation of this activity.