[Effect of T-activin on thymocyte reproduction and migration]

Forty seven F1 (CBA X C57Bl) mice were used for quantitative morphologic examination of the thymus on 1, 5, 10 and 15 days after a single injection of 0.5 microgram T-activin, and injections of 0.1 microgram of T-activin once a day during 5 days. The number of transformed thymocytes and mitoses figures in cortex was found to be increased reaching a maximum at the 5th day as regards the magnitude and spreading. By the end of the research the number of transformed thymocytes and mitoses returned to initial values. There was a periodical (at the 5th and 10th days) 1 mm2 reduction in the number of thymocytes, an increase in the proportion of medullary thymocytes, reaching maximum at the 5th day, and a tendency towards the reduction of a relative area of the parenchyma. These indicators did not return to the initial values by the 15th days. However there was a tendency towards normalization. The conclusion is made about the stimulatory effect of T-activin on reproduction and migration of thymocytes.