Effect of Orchidectomy and Ovariectomy on Survival against Lethal Infections in Mice

Abstract

THE reticulo-endothelial system plays a predominant part in the defence of the body against infection. We have previously shown that stimulation of the reticulo-endothelial system leads to raised body defence (indicated by increased phagocytic activity, accelerated antibody production, raised serum gamma globulin and increased protection of experimental animals against virulent infections), and that the strongest reticulo-endothelial stimulants are the oestrogens^1,2. We have also shown that the action of oestrogen on the reticulo-endothelial system is independent of its action on the reproductive tract, although these two biological activities are contained in the same molecule³. We have also demonstrated that cyclical variations in reticulo-endothelial activity occur during the oestrous cycle and during pregnancy in the rat and the mouse¹. These findings suggest that when protection against infection is required, general and local body defence is increased by raised blood oestrogen levels. We also found that reticulo-endothelial activity falls after ovariectomy in the mouse⁴. These results suggest that oestrogen, especially 17β-oestradiol, is the principal natural stimulant of body defence in both the male and the female—the latter having raised oestrogen levels when protection against infection is normally most needed.