Using tritiated-thymidine incorporation as a measure of cell growth, interleukin-1β stimulated the growth of bovine zona fasciculata/reticularis adrenocortical cells after 72h in primary culture. Within the range of 10–1000pg/ml, interleukin-1β produced over 40% of angiotensin II-stimulated [3H]thymidine incorporation (P<0.005 compared with basal for 10pg/ml and 1000pg/ml; P<0.05 for 100pg/ml; two-tailed unpaired Student's t-test). Interleukin-1β did not directly stimulate cortisol secretion.
By stimulating adrenocortical growth, the increase in interleukin-1 during fever provides a potential mechanism for chronically raising glucocorticoid output. This study is the first demonstration of a long-term effect involving interleukin-1β on the adrenal cortex.