title: Spleen regeneration in mice after gamma irradiation and administration of thymosin.
abstract: The effect of thymosin (thymic humoral factor isolated from calf thymus) on regeneration of the spleen in mice after whole-body gamma irradiation was studied. Thymosin, in varied dosages (0.1--2.0 mg/day) applied subcutaneously before and after radiation exposure, stimulated splenic regeneration as indicated by increased splenic weight, number of endogenous splenic colonies and 59Fe and 125IUdR incorporation into the spleen. A control extract of brain tissue (cerebrosin) isolated in the same way as thymosin was applied to mice to verify specificity of thymosin. After cerebrosin application, a mild increase also was observed. Whereas a near maximal effect of thymosin was reached at a dosage of 0.1 mg, a comparable response with cerebrosin required a dosage of 1.0 mg. These data suggest that administration of thymosin has both a specific and non-specific effect on splenic regeneration and proliferation of hematopoietic stem cells.
mesh_terms: D000818:Animals; D001921:Brain; D002417:Cattle; D003114:Colony-Forming Units Assay; D005260:Female; D006410:Hematopoiesis / Q000187:drug effects* / Q000528:radiation effects; D051379:Mice; D008815:Mice, Inbred Strains; D011832:Radiation Injuries / Q000188:drug therapy*; D013154:Spleen / Q000187:drug effects / Q000528:radiation effects; D013947:Thymosin / Q000302:isolation & purification / Q000627:therapeutic use*; D013951:Thymus Hormones / Q000627:therapeutic use*; D014020:Tissue Extracts / Q000627:therapeutic use
chemical_list: D013951:Thymus Hormones; D014020:Tissue Extracts; C024099:cerebrosin; D013947:Thymosin