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Testicular dysfunction in men with primary hypothyroidism; reversal of hypogonadotrophic hypogonadism with replacement thyroxine
Author(s) -
Donnelly Peter,
White Christopher
Publication year - 2000
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1046/j.1365-2265.2000.00918.x
Subject(s) - hypogonadotrophic hypogonadism , medicine , endocrinology , hypogonadotropic hypogonadism , testosterone (patch) , prolactin , testosterone replacement , hyperprolactinaemia , central hypothyroidism , androgen , hormone
OBJECTIVE Primary hypothyroidism can cause disturbances in normal gonadal function. The aim of this study was to investigate the relationship in men between hypogonadism and primary hypothyroidism and the extent to which free and total testosterone levels rose after introduction of replacement thyroxine. DESIGN Paired study of patients in a hypothyroid and thyroxine treated state. PATIENTS Ten men with primary hypothyroidism. MEASUREMENTS Free and total testosterone, gonadotrophin and prolactin levels before and after thyroxine replacement therapy. RESULTS Low free testosterone levels (161 ± 62 pmol/l) demonstrated at the time the men were hypothyroid rose significantly with the commencement of thyroxine replacement (315 ± 141 pmol/l; P < 0.001). Gonadotrophin levels were not elevated consistent with hypogonadotrophic hypogonadism. Hyperprolactinaemia, which can occur in primary hypothyroidism and cause hypogonadotrophic hypogonadism, was not present in the majority of these patients. However a reduction in prolactin level was evident with thyroxine replacement and a rise in free testosterone levels. CONCLUSION This suggests an effect of hypothyroidism on gonadotrophin secretion at the level of the hypothalamus‐pituitary, either directly or through modulation of prolactin secretion. Low free testosterone may also be a contributing factor to some of the symptoms and signs of hypothyroidism in men.