Hormonal influences on the secretion of the thymus

The bibliography concerning the interaction of the thymus with other endocrines is summarized. The thymus, the lymph nodes and the spleen of Sprague-Dawley rats were extracted with the method of Bezssonoff and Comsa and the extracts fractionated with the method of Bernardi and Comsa. The animals were (1) normal, (2) adrenalectomized, (3) adrenalectomized and substituted with one or several corticosteroids, (4) adrenalectomized and thymectomized, (5) thyroidectomized, (6) thyroidectomized and substituted with thyroxine, (7 and 8) castrated (males or females), (9 and 10) castrates substituted with sexual hormones, (11) castrated and adrenalectomized, (12) castrated and thyroidectomized, (13) castrated, adrenalectomized and thyroidectomized, (14) hypophysectomized, and (15) hypophysectomized and substituted with one hypophyseal hormone. In the Bernardi-Comsa preparations hormone was determined by UV-spectrophotometry. Adrenalectomy resulted in a significant decrease of the hormone content of the thymus (which was still more attenuated by cortisol) and its increase in the lymph nodes and the spleen. Corticosterone and desoxycorticosterone increased the hormone content in all three tissues, whilst aldosterone increased it in the thymus and decreased it in the lymph nodes and the spleen. Thyroidectomy resulted in a significant decrease of the hormone in the thymus and its quasi-disappearance from the lymph nodes and the spleen. This was prevented by thyroxine therapy. Castration resulted in an increase of the hormone content in all three tissues. This was prevented by sexual hormone therapy. Hypophysectomy resulted in decrease of the hormone content in all three tissues. This was prevented by injections with growth hormone, corticotropin and thyrotrophin. These results were compared with those of histological examinations of thymus, lymph nodes and spleen in the corresponding experimental groups. The consistency was found satisfactory.