A newly published study of 104 acne patients, which appears to have been part of the Turkish science and technology bureau’s investigation of Accutane/Isotretinoin, shows significantly decreased thyroid gland volume, decreased levels of thyroid hormones, and increased levels of thyroid stimulating hormone (TSH).
They also discuss the results of previous related studies over the years:
It has long been known that high doses of vitamin A can interfere with the effects of thyroid hormone metabolism. Sadhu and Brody demonstrated a 10% decrease in oxygen consumption, a depressed metabolic rate and, interestingly, a 35% decrease of thyroid weight in euthyroid rats given high doses of vitamin A.The effect of vitamin A and retinoids on the hypothalamic-pituitary-thyroid axis has been well recognized but poorly understood.,
Retinoids can affect cell growth, differentiation, function and metabolism via two groups of nuclear hormone receptors: retinoic acid receptors and retinoid X receptors. These receptors also mediate the activity of steroid and thyroid hormones.