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This Article Full Text Full Text (PDF) All Versions of this Article: 294/5/R1504    most recent 00027.2008v2 00027.2008v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Schlenker, E. H. Articles by Gerdes, A. M. PubMed PubMed Citation Articles by Schlenker, E. H. Articles by Gerdes, A. M.

NEUROHUMORAL CONTROL OF CARDIOVASCULAR FUNCTION

Effects of thyroidectomy, T₄, and DITPA replacement on brain blood vessel density in adult rats

¹Basic Biomedical Sciences, Sanford School of Medicine of the University of South Dakota, Vermillion; ²Cardiovascular Research Center, Sanford Research/University of South Dakota, Sioux Falls, South Dakota; and ³Sarver Heart Center, University of Arizona, Tucson, Arizona

Submitted 14 January 2008 ; accepted in final form 17 March 2008

In hypothyroid patients, altered microvascular structure and function may affect mood and cognitive function. We hypothesized that adult male hypothyroid rats will have significantly lower forebrain blood vessel densities (BVD) than euthyroid rats and that treatment with 3,5-diiothyroprionic acid (DITPA) (a thyroid hormone analog) or thyroxine (T₄) will normalize BVDs. The euthyroid group received no thyroidectomy or treatment. The other three groups received thyroidectomies and pellets. The hypothyroid group received a placebo pellet, the DITPA group received an 80-mg DITPA-containing pellet, and the T₄ group received a 5.2-mg T₄ slow-release pellet for 6 wk. Body weights, cardiac function, and body temperatures were measured. A monoclonal antiplatelet endothelial cell adhesion antibody was used to visualize blood vessels. The euthyroid group averaged body weights of 548 ± 54 g, while the hypothyroid group averaged a body weight of 332 ± 19 g (P value < 0.001). Relative to the euthyroid group, the DITPA-treated group was significantly lighter (P value < 0.05), while the T₄-treated group was comparable in body weight to the euthyroid group. The same trends were seen with body temperature and cardiac function with the largest difference between the euthyroid and hypothyroid groups. BVD in the euthyroid group was 147 ± 12 blood vessels/mm² and in hypothyroid group 69 ± 5 blood vessels/mm² (P = 0.013) but similar among the euthyroid, DITPA, and T₄ groups. These results show that hypothyroidism decreased BVD in adult rat forebrain regions. Moreover, DITPA and T₄ were efficacious in preventing effects of hypothyroidism on cardiac function and BVD.

hypothyroid; angiogenesis; echocardiography; thyroid hormones