[Dynamics of indices of the rat endocrine and lymphatic systems during cold adaptation].

A study was made of the content of corticosterone, thyroxine and triiodothyronine in the blood, of the thymic weight and cytomorphological characteristics of rat lymph nodes during prolonged cold (4-5 degrees C) adaptation. Interrelated alterations in the characteristics under study were revealed at different stages of adaptation. The morphofunctional recovery of the lymphoid tissue occurs in the phase of the increased specific stability in spite of the fact that the action of cold is continued and the blood corticosterone concentration is elevated. A new type of the endocrine-lymphoid relationships is supposed to be formed during lengthy adaptation, with this type being different from that both in the starting state and acute stress.