Enhancement of transplantable neoplastic tissue growth in rats by ligated vasectomy and long-term exercise.

The long-term effects of vasectomy and exercise upon incidence and frequency of neoplastic lesions in preselected categories, number of neoplasms by morphologic type, anatomic site and weight, selected body and organ weights, and survival experience of rats receiving a transplantable pancreatic carcinoma were determined. Vasectomy-exercise subjects had a significantly greater incidence of neoplasms at multiple anatomic sites as compared to sedentary subjects, but not with other exercised ones. Vasectomy-sedentary subjects had a higher incidence of multiple neoplastic lesions of the same anatomic site than sedentary controls. Ligated vasectomies may accelerate transplantable neoplastic tissue growth. Vasectomy-exercise subjects had a greater total number of discrete, fused, both discrete and fused neoplasms, and different anatomic sites of fused neoplasms compared to sedentary controls. Ligated vasectomy groups had significantly heavier body weights at necropsy than shamvasectomized control groups. Sham-vasectomy-exercise subjects had significantly heavier relative liver weights than shamvasectomy-sedentary controls. There was not a significant difference between groups in survival experience. Conditions associated with the ligated-vasectomy state and the physiologic consequences of moderate exercise may accelerate transplantable neoplastic tissue growth in Lewis rats.