which is the thymus secret of the hormones?
Answers
The thymus produces several polypeptides, which induce lymphocyte differentiation in vitro and in vivo. Several of these polypeptides have been chemically characterized, and three of them have been sequenced and synthesised (alpha 1 thymosin, thymopoietin and the serum thymic factor). Thymic hormones do not act identically on all T-cell subsets: they alter preferentially post-thymic precursor cells, and among mature T cells cytotoxic cells and suppressor cells. Their mode of action at the cellular level involves binding to specific cellular receptors and interaction with adenyl cyclase. Preliminary clinical trials with crude extracts have provided promising results in immunodeficient and cancer patients. The differentiation of T cells from stem cells has been the matter of considerable investigation over the last two decades, since it has been realized that the thymus and its products, the thymus-derived cells (T cells) play a central role in the generation of effector cells in cell-mediated immunity and in the regulation of the various categories of immune responses. That the thymus could act by the intermediate of humoral substances was precociously suggested by MILLER and OSOBA before the observation that thymuses grafted within a cell-impermeable Millipore diffusion chamber restored the immunocompetence of neonatally thymectomized (Tx) mice