Doi_1990_Endocrinology_127_857

Congenital defects in thyroglobulin (Tg) synthesis in animals have proven to be useful models for the study of Tg synthesis and regulation. Defects in Tg synthesis have been well described in Afrikander cattle, Australia Merino sheep, and goats in The Netherlands. This report describes a study of goiter in a nondomesticated bovine species, bongo antelope (Tragelaphus eurycerus), an African bovid. Three animals housed at the National Zoological Park, Washington, D.C. were studied; two had visible goiters, and a third bongo had microscopic evidence of goiter. Tg extracted from thyroid glands or thyroid colloid from these animals had a high mol wt component that was greater than 220K daltons and differed in apparent mol wt from 19S Tg from domestic cattle. Thyroid extracts also had thyroid albumin; albumin was more than half the total protein in colloid extract. The animals with goiter were euthyroid according to their circulating levels of thyroid hormones.