To verify the effects produced by the injections of hyperosmotic substances into the prostate of Wistar rats as judged by gland weight, behavior, histologic changes, and systemic electrolytic alterations. A total of 42 Wistar rats were divided into five groups and treated in the following manner. In Group I (N = 6), the abdominal cavity was opened and closed. In Group II (N = 6), a needle was introduced into the each ventral lobes of the prostate gland. In Group III (N = 10), a 0.9% sodium chloride solution was injected into the each ventral lobe of the prostate gland. In Group IV (N = 10), a 20% NaCl solution was injected into the each ventral lobe of the prostate gland. In Group V (N = 10), a 50% glucose solution was injected into the each ventral lobe of the prostate gland. The following parameters were studied: histologic features of the ventral lobes of the prostate, the electronic weight of the parts utilized in the surgery, and the sodium and potassium concentrations. The animals of Group V (50% glucose solution) were sacrificed after 60 days and showed a significant reduction in the weight of the ventral prostate lobes in comparison with the other groups (P = 0.05). There were important histologic changes in the groups which received hyperosmotic substances. After the 50% glucose injection, the potassium level increased temporarily. The injection of 50% glucose solution produced significant alterations in the tissue structure, with reduction in prostatic weight. The electrolyte changes were transitory.16127-32