The methyl xanthines--a new class of goitrogens.

TLDR: The methyl xanthines are mildly antithyroid and strongly goitrogenic compounds and the possibility that this dissociation between the antithYroid and goitrogensic response involves mediation by 3′,5′-AMP is discussed.

Abstract: Rats chronically fed methyl xanthines in a low iodine diet developed goiters. The potency of the compounds tested was in the order: theophylline =aminophylline> caffeine > theobromine. Goitrogenesis was reduced on high iodine diets and absent in hypophysectomized rats. Theophylline caused marked, synergistic enhancement of the goitrogenic effect of small doses of propylthiouracil. Aminophylline and theophylline lowered the PBI but at theophylline concentrations prevailing in these sera little antithyroid activity could be demonstrated in rat thyroid segments in vitro. It is concluded that the methyl xanthines are mildly antithyroid and strongly goitrogenic compounds. The possibility that this dissociation between the antithyroid and goitrogenic response involves mediation by 3′,5′-AMP is discussed. (Endocrinology 85: 410,1969)