• Castration;
  • digital image;
  • ovary;
  • reticuloendothelial system;
  • testis

PROBLEM: The presence of androgen and estrogen receptors in macrophages was recently described. This suggests that both sex hormones directly act on reticuloendothelial system (RES) activity. Studies of the effect of gonadectomy on uptake and clearance of foreign materials make clear a role of the testis and ovary in RES regulation. However, there is still some disagreement as to the gonadal influence on RES. METHOD OF STUDY: We applied a computed image analysis system to the investigation of the effects of gonadectomy on colloidal carbon uptake by the liver and spleen sinusoidal cells in mice. Mice were gonadectomized or sham-operated. After a few weeks, they received colloidal carbon with or without pretreatment with lipopolysaccharide (LPS). Thereafter, livers and spleens were taken for quantitative determination of the amounts of endocytosed carbon in the sinusoidal cells by means of digital image analysis. RESULTS: Ovariectomy did not significantly affect hepatic and splenic RES activities compared with sham-operated controls. Treatment of mice with LPS after ovariectomy also caused no significant changes of the RES activities compared with sham-operated and LPS-injected controls. In contrast, orchidectomy resulted in significant enhancement of splenic RES activity compared with sham-operated males, while hepatic RES activity did not significantly change with orchidectomy alone. However, LPS treatment to orchidectomized mice significantly augmented both hepatic and splenic RES activities compared with sham-operated and LPS-injected controls. CONCLUSION: The significant augmentation of RES activity by orchidectomy, but not by ovariectomy, indicates that male RES activity is physiologically downregulated in the presence of the testes. Furthermore, splenic RES is more sensitive to orchidectomy than hepatic RES.