STUDIES ON RETROGRADE PROTEUS MIRABILIS PYELONEPHRITIS IN THE RAT

III. Study of the plasma corticosterone on the concomitant thymic involution

Abstract

The causes of the accidental thymic involution are speculated upon the increased secretion of glucocorticoids from the adrenal glands, the mobilization of T-cells from the thymus and others.
To investigate the causes of the concomitant thymic involution in retrograde Proteus mirabilis pyelonephritis in the rat, plasma corticosterone was measured with rats which were sacrificed daily from 1 to 7 days after challenge of Proteus mirabilis. The correlation between the plasma corticosterone and the thymus weight and the spleen cell response to concanavalin A as an index of T-cell function was investigated.
In the rats with renal abscesses, a marked decrease of thymus weight and a remarkably increased adrenal weight were simultaneously observed, and there was a correlation between them. Histologically, an increase of adrenal weight was depended upon cortical hypertrophy. The plasma corticosterone, however, was not correlated to either adrenal weight, severity of the renal disease, thymus weight or spleen cell response to concanavalin A.
These observations suggested that the plasma corticosterone was not the main cause of the concomitant thymic involution in retrograde Proteus mirabilis pyelonephritis in the rat.