Carcinogenesis and aging. IV. Effect of low-molecular-weight factors of thymus, pineal gland and anterior hypothalamus on immunity, tumor incidence and life span of C3H/Sn mice

The low-molecular-weight polypeptide factors were obtained from bovine thymus (TF), pineal gland (PF) and anterior hypothalamus (AHF). Both TF and PF administration enhanced the rejection of skin allograft and stimulated the immunological response to sheep erythrocytes in adult CBA mice. Treatment of CBA mice with AHF increased the graft survival and inhibited antibody formation to sheep erythrocytes. Chronic TF or PF administration decreased spontaneous tumor development and prolonged the life span of female C3H/Sn mice. Administration of AHF failed to influence the life span and the tumor incidence of female C3H/Sn mice. The role of immunity and hormonometabolic shifts in mechanisms of both aging and the age-associated increase in cancer incidence are discussed.