Reduced interleukin-1 responsiveness in immune system and central nervous system of inbred polydipsic (STR/N) mice

Inbred polydipsic mice (STR/N strain) have primary polydipsia. The previous studies found abnormalities in the central nervous system (CNS), especiall y in the hypothalamus and circumventricular organ. As a part of pursuing to find the cause of the polydipsia, we investigated immunological characteri stics of STR/N mice, using the ICR strain of mice as control. Their thymic subset cells showed that CD4(+)CD8(+) double positive cells were increased, CD4(+) single positive cells were decreased and CD5 expression was deficie nt, compared to ICR mice. T cell proliferative response and interleukin (IL )-2 production caused by IL-1 beta stimulation were reduced in STR/N mice t han those in the ICR mice. In in vivo studies the degree of thymic atrophy and the increases in serum level of ACTH and corticosterone induced by intr aperitoneal IL-1 beta injection were much less in STR/N mice than those in controls. Furthermore, adipsic response also induced by IL-1 beta injection was greatly reduced compared to their control mice. All these results sugg est that the responsiveness to IL-1 is impaired both in the immune system a nd the CNS of STR/N mice.