Interleuklin 1-β injected into the testis acutely stimulates and later attenuates testicular steroidogenesis of the immature rat

The effect of intratesticular administration of interleukin-1 beta (IL-1 beta) on steroidogenesis was studied in immature and adult rats. In 21-d-old animals local bilateral injection or unilateral administration of 0.1 mu g/testis of IL-1 beta to hemicastrates resulted in a significant increase in basal testosterone secretion in vitro and serum testosterone concentration one day posttreatment. Six days after treatment the cytokine induced opposite effect in animals with two testes in situ, i.e., it suppressed steroidogenesis. When IL-1 beta was combined with hemicastration, IL-1 beta failed to alter the parameters studied. in adult animals subjected to bilateral treatment or to unilateral injection followed by hernicastration, IL-1 beta in doses of 1.5 mu g/testis or 15 mu g/testis did not influence steroidogenesis and serum testosterone concentration. No change in serum LH and FSH concentration could be observed in any experimental group. The data suggest that the proinflammatory cytokine IL-1 beta exerts a local action on testicular steroidogenesis, and the effect is age-dependent.