Open AccessEffect of 131 I‐Induced Hypothyroidism on Indices of Reproductive Function in Adult Male Dogs
Author(s) -
Johnson Cheri,
Olivier N. Bari,
Nachreiner Raymond,
Mullaney Thomas
Publication year - 1999
Publication title -
journal of veterinary internal medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.356
H-Index - 103
eISSN - 1939-1676
pISSN - 0891-6640
DOI - 10.1111/j.1939-1676.1999.tb01137.x
Subject(s) - euthyroid , medicine , endocrinology , testosterone (patch) , libido , thyroid , luteinizing hormone , hormone , semen quality , thyroid function , infertility , decreased libido , secondary sex characteristic , physiology , sperm , reproductive system , biology , pregnancy , andrology , genetics
Hypothyroidism has been cited as a cause of infertility, abnormal semen quality, and poor libido in people and animals. The purpose of this study was to evaluate the effect of hypothyroidism on variables indicative of reproductive function in adult male dogs. Nine normal dogs were randomly assigned to 2 groups. Hypothyroidism was induced with 131 I in 6 dogs. Three dogs remained untreated, normal, and euthyroid. Thyroid hormone concentrations, body weight, clinical signs, and reproductive function were determined for each dog every 3 months for 2 years. Reproductive function was assessed by determining daily sperm output, total scrotal width, spermatozoal motility and morphology, libido, and serum testosterone and luteinizing hormone concentration responses to exogenous gonadotropin‐releasing hormone. The 131 I‐treated dogs developed clinical and laboratory signs of hypothyroidism. In the hypothyroid dogs, serum concentrations of thyroid hormones were consistently below the reference range and were significantly lower than that in the euthyroid dogs. There was no difference in reproductive function between the hypothyroid and euthyroid dogs. The results of this study show that 131 I‐induced hypothyroidism does not affect indices of reproductive function in adult male dogs.