Impact of thyroid disease on testicular function.

INTRODUCTION: Testis was considered unresponsive to thyroid hormone for a long time. However, like in animals, the presence of thyroid hormone receptors in different testicular cell types was demonstrated also in humans. Accordingly, thyrotoxicosis and hypothyroidism have remarkable effects on testicular function and more extensively on fertility. REVIEW: Thyrotoxicosis and hypothyroidism are associated with changes affecting the endocrine, sexual, or reproductive functions. Particularly, compared with controls, hyperthyroid patients have higher serum SHBG and lower free and bioavailable testosterone concentrations, a higher rate of astheno-zoospermia, oligo-zoospermia, and terato-zoospermia, and a higher prevalence of sexual disturbances, such as premature ejaculation. In hypothyroid patients, hormonal changes are in the opposite direction compared with hyperthyroid patients. Thyroid hormone regulates a number of functions in the testis, such as proliferation and differentiations of non-germ cells, steroidogenesis, and sperm motility. Furthermore, thyroid hormone regulates testicular redox status. Consequently, thyroid hormone excess or deficiency can affect testicular function at different levels. CONCLUSIONS: In view of the high prevalence of thyrotoxicosis and hypothyroidism, a considerable part of infertile patients may harbor overt or subclinical thyroid disease. Identification and management of thyrotoxicosis/hypothyroidism associated infertility needs the collaboration of andrologists, endocrinologists, gynecologists, and general practitioners.

Radioiodine ablation of postsurgical thyroid remnants after treatment with recombinant human TSH (rhTSH) in patients with moderate-to-severe graves' orbitopathy (GO): a prospective, randomized, single-blind clinical trial.

CONTEXT: Recent evidence suggests thyroidectomy (Tx) followed by radioiodine remnant ablation to be beneficial to Graves' orbitopathy (GO) patients. OBJECTIVE: The aim of the study was to evaluate the effect of (131)I thyroid ablation after recombinant human TSH stimulation in patients with moderate-to-severe GO. DESIGN, PATIENTS, AND INTERVENTIONS: The study was prospective, randomized, and single-blind, and it included 40 consecutive patients with moderate-to-severe GO randomized into: 1) a Tx-radioactive iodine (RAI) group (20 subjects who underwent total-Tx and (131)I ablation after recombinant human TSH stimulation); and 2) a Tx group (20 subjects who underwent total-Tx alone). OUTCOME MEASURES: The overall GO outcome 12 months after Tx/radioiodine ablation was the main measure. RESULTS: GO evaluation at the end of iv glucocorticoids showed eye disease to be improved in 65% of the Tx-RAI group and 60% of the Tx group patients. At 6 and 12 months, no further changes in the GO outcome could be observed in the Tx-RAI group. Conversely, five patients from the Tx group exhibited a deterioration in GO. At 12 months, GO was found to be improved in 70% of the Tx-RAI and 20% of the Tx group patients, the latter being found to be stable (55%) or worse (25%) than at baseline evaluation. At 12 months, GO was found to be inactive in a significantly higher percentage of patients in the Tx-RAI than in the Tx group (75 vs 30%; P < .01). CONCLUSIONS: Postoperative radioiodine ablation proved more effective than Tx alone in inducing earlier and steadier GO improvement in patients with moderate-to-severe GO treated with iv glucocorticoids over a 24-month follow-up period.