Exp Clin Endocrinol Diabetes 2016; 124(02): 71-76
DOI: 10.1055/s-0035-1565207
Article
© Georg Thieme Verlag KG Stuttgart · New York

The Effect of Metformin on Hypothalamic-Pituitary-Thyroid Axis Activity in Women with Interferon-Induced Hypothyroidism: A Pilot Study

R. Krysiak
1   Department of Internal Medicine and Clinical Pharmacology, Medical University of Silesia, Katowice, Poland
,
W. Szkrobka
1   Department of Internal Medicine and Clinical Pharmacology, Medical University of Silesia, Katowice, Poland
,
B. Okopien
1   Department of Internal Medicine and Clinical Pharmacology, Medical University of Silesia, Katowice, Poland
› Author Affiliations
Further Information

Publication History

received 07 September 2015
revised 26 October 2015

accepted 31 October 2015

Publication Date:
19 February 2016 (online)

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Abstract

Background: One of the most frequent adverse effects of interferon-α therapy is thyroiditis. Metformin was found to improve insulin sensitivity in hepatitis C patients, as well as to reduce elevated thyrotropin levels in patients with hypothyroidism. The aim of this study was to investigate the effect of metformin on hypothalamic-pituitary-thyroid axis activity in patients with interferon-induced thyroiditis.

Methods: The study included 2 matched groups of women with type 2 diabetes and untreated subclinical hypothyroidism: patients with interferon-induced thyroiditis (n=8) and patients with Hashimoto’s thyroiditis (n=12). Fasting plasma glucose, the homeostatic model assessment 1 of insulin resistance ratio (HOMA1-IR), glycated hemoglobin, the estimated glomerular filtration rate, as well as serum levels of thyrotropin, thyroid hormones, prolactin and insulin-like growth factor-1 (IGF-1) were assessed at baseline and after 4 months of metformin treatment.

Results: Apart from reducing plasma glucose, HOMA1-IR and glycated hemoglobin, metformin decreased serum levels of thyrotropin. Circulating levels of thyroid hormones, prolactin and IGF-1 remained at a similar level throughout the study. The effect of metformin on serum thyrotropin was stronger in patients with interferon-induced thyroiditis than in patients with Hashimoto’s thyroiditis, as well as correlated with its impact on insulin sensitivity.

Conclusions: Our results indicate that metformin may be an effective agent in patients with interferon-induced hypothyroidism.