STUDIES ON THE RATES OF INVOLUTION AND RECONSTITUTION OF LYMPHATIC TISSUE1

Abstract

The influences of fasting and refeeding on lymphatic tissue of intact and adrenalectomized CBA mice were studied. The percentage loss of lymphatic tissue wt. of intact-fed mice far exceeded the percentage loss of body wt. during a 96-hr. fast. Individual lymphatic organs differed in rate and degree of involution. The mitotic rate of lymphatic tissue cells was inhibited by inanition. Adrenalectomy during an uninterrupted fast arrested the involution of lymphatic tissue and resulted in a higher mitotic rate than that found in intact-fed mice. The body wt. of intact-refed mice underwent a more rapid reconstitution than the wt. of lymphatic organs, whereas the lymphatic organs of adrenalectomized-refed mice reconstituted more rapidly than the body wt. Individual differences in rate of lymphatic organ reconstitution were abolished by adrenalectomy. The N content / unit wt. of lymphatic tissue remained the same in both intact and adrenalectomized mice during fasting and re-feeding. These data support the suggestion that lymphatic tissue protein is made available for metabolic use by adrenocortical mediation. It is also suggested that the fasting-refeeding method of study can be used as a method for the bio-assay of compounds and/or nutritional factors which produce either involution or growth of lymphatic tissue.