VASCULAR CONNECTIVE TISSUE UNDER THE INFLUENCE OF THYROXINE

Abstract

ABSTRACT Aortae were studied in three groups of rabbits: First group: Injected with epinephrine for two weeks and with 1-thyroxine for another two weeks. Second group: Injected with epinephrine for two weeks and with physiological saline for another two weeks. Third group: Untreated controls. The aortae were assessed by gross and microscopic examination, and the content of water, hexosamine, hydroxyproline and calcium as well as the in vivo uptake of 35S sulphate determined. The alterations in the epinephrine-thyroxine-treated group were not so pronounced as previously observed after simultaneous injections of epinephrine plus 1-thyroxine. But the thyroxine injections in this group brought about a clear-cut increase in hexosamine content and 35S sulphate uptake as compared with the untreated controls. This presumably indicates that owing to the thyroxine treatment the vascular wall was still exposed to damage despite the discontinuation of the epinephrine injections. In contradistinction, the epinephrine-saline-treated rabbits did not differ significantly from the controls as regards biochemical changes in the aortic wall two weeks after discontinuation of epinephrine. When the microscopic appearance were also considered, this was interpreted as a sign of cessation of the injuries to the vascular wall and of healing.