Orchidectomy and the immune response. I. Effect of orchidectomy on lymphoid tissues of mice.

Abstract

The effects of pre- and postpuberal orchidectomy on the lymphoid tissues of mice have been studied. Prepuberal orchidectomy delayed the normal rate of thymic involution and caused relative hypertrophy of the thymus which was maximal 1 month after surgery. There was also enlargement of the peripheral lymph nodes to reach a sustained maximum by 6 weeks and also an increase of spleen size. Histological examination of the enlarged thymus showed widening of the cortex and medulla with increased cell density. The enlarged peripheral lymph nodes showed widening of the paracortical area which is thymus dependent. Synchronous thymectomy and orchidectomy prevented the lymph node enlargement that follows orchidectomy alone, but it did not affect the increase of spleen size until 3 months after surgery. After postpuberal orchidectomy thymic size increased to a maximum at 1 month and the increase of peripheral lymph node mass and spleen mass was less than the changes following prepuberal surgery ; only 3 months after operation was the lymph node mass of orchidectomized mice significantly greater than controls and changes in spleen mass were only apparent after correction for changes in body mass.