Effects of Thyroid Status on Pituitary Gonadotropin and Testicular Reserve in Men

Velazquez, Elsy; Arata, G. Bellabarba

doi:10.3109/01485019708988535

Cited by 51 publications

(33 citation statements)

References 15 publications

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“…Most studies indicated that hypothyroid men with hypogonadism have normal LH and FSH levels, suggesting that the primary defect is not in Leydig cells and presumably results from a defect at the hypothalamus and/or pituitary level. Blunted Gn responses to GnRH support this notion, and it would therefore seem that primary hypothyroidism impairs the ability of the pituitary gland to respond to GnRH (41). Another finding that supports the above notion is that hCG produces an exaggerated response of serum testosterone in such patients, which is in contrast with what is expected if the primary defect was in Leydig cells.…”

Section: B Hypothyroidism In Malesmentioning

confidence: 72%

Thyroid Function and Human Reproductive Health

Krassas¹,

2010

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Via its interaction in several pathways, normal thyroid function is important to maintain normal reproduction. In both genders, changes in SHBG and sex steroids are a consistent feature associated with hyper- and hypothyroidism and were already reported many years ago. Male reproduction is adversely affected by both thyrotoxicosis and hypothyroidism. Erectile abnormalities have been reported. Thyrotoxicosis induces abnormalities in sperm motility, whereas hypothyroidism is associated with abnormalities in sperm morphology; the latter normalize when euthyroidism is reached. In females, thyrotoxicosis and hypothyroidism can cause menstrual disturbances. Thyrotoxicosis is associated mainly with hypomenorrhea and polymenorrhea, whereas hypothyroidism is associated mainly with oligomenorrhea. Thyroid dysfunction has also been linked to reduced fertility. Controlled ovarian hyperstimulation leads to important increases in estradiol, which in turn may have an adverse effect on thyroid hormones and TSH. When autoimmune thyroid disease is present, the impact of controlled ovarian hyperstimulation may become more severe, depending on preexisting thyroid abnormalities. Autoimmune thyroid disease is present in 5-20% of unselected pregnant women. Isolated hypothyroxinemia has been described in approximately 2% of pregnancies, without serum TSH elevation and in the absence of thyroid autoantibodies. Overt hypothyroidism has been associated with increased rates of spontaneous abortion, premature delivery and/or low birth weight, fetal distress in labor, and perhaps gestation-induced hypertension and placental abruption. The links between such obstetrical complications and subclinical hypothyroidism are less evident. Thyrotoxicosis during pregnancy is due to Graves' disease and gestational transient thyrotoxicosis. All antithyroid drugs cross the placenta and may potentially affect fetal thyroid function.

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Section: B Hypothyroidism In Malesmentioning

confidence: 72%

Thyroid Function and Human Reproductive Health

Krassas¹,

2010

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“…Previous studies indicated that patients with hypothyroidism demonstrated a defective LH response to GnRH [27] and a decrease in the blood level of LH and TSH causing testicular dysfunction [28].…”

Section: Discussionmentioning

confidence: 99%

Investigation on the Histopathological Effects of Thyroidectomy on the Seminiferous Tubules of Immature and Adult Rats

Öncü

Kavaklı²,

Gökçimen³

et al. 2004

Urol Int

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Introduction: This study aimed to investigate the histopathological effects of thyroidectomy on both immature and adult rat testes. Materials and Methods: Male albino Wistar rats, 4 weeks old and weighing between 45 and 55 g, were used for this study. The experimental groups were as follows: 2-week control group (group I); 2-week thyroidectomy group (group II); 4-week control group (group III); 4-week thyroidectomy group (group IV); 6-week control group (group V), and 6-week thyroidectomy group (group VI). The control groups included both sham-operated and untreated rats. In groups II, IV and VI, total thyroidectomy was performed under ether anesthesia in all rats at 4 weeks of age. The rats were killed in the 2nd, 4th and 6th weeks, respectively, following the thyroidectomy. The testes of each animal were evaluated histologically. Results: In group II, spermatogenesis progressed to meiosis but round spermatids were found to be decreased and pachytene spermatocytes were observed to be increased when compared to group I. Giant pachytene spermatocytes were seen. There were also many degenerated cells of intermediate origin in the seminiferous epithelium. In groups IV and VI, spermatogonia and primary spermatocytes were normal in appearance, but there was widespread degeneration of the other spermatogenic cells. In addition, some closed lumina covered by degenerated and dead cells were observed. In group II, the mean outer diameter, luminal diameter and area occupied by seminiferous epithelium decreased by 19.74, 32.18, and 28.12%, respectively. In group IV, these data decreased by 23.9, 16.52, and 48.5%, respectively, and in group VI, by 21.10, 19.76 and 40.29%, respectively, when compared with the control groups. These data were statistically significant (p < 0.001). Conclusions: Thyroid hormones could have a marked influence on the seminiferous tubules of both immature and adult rats, and their permanent lack results in a depression in seminiferous tubule growth as shown by the reduced outer and luminal diameters and area occupied by the seminiferous epithelium, which could give rise to degenerative changes in the spermatogenic cells of thyroidectomized rats. In addition, all these changes could also result from both the inability of Sertoli cells to support spermatogenic cells and the diminished levels of GH and FSH.

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“…On the other hand, hyperthyroid men have increased 17-hydroxy (17-OH) progesterone, T, and E2 [1,14,30,34,41,47,49,55,101]. The increased level of E2 may be due to increased peripheral metabolism of androgens into estrogen [90].…”

Section: Serum Sex Steroids Under Altered Thyroid Statusmentioning

confidence: 99%

Thyroid Hormones: Their Role in Testicular Steroidogenesis

Maran

2003

Archives of Andrology

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Effects of Thyroid Status on Pituitary Gonadotropin and Testicular Reserve in Men

Cited by 51 publications

References 15 publications

Thyroid Function and Human Reproductive Health

Thyroid Function and Human Reproductive Health

Investigation on the Histopathological Effects of Thyroidectomy on the Seminiferous Tubules of Immature and Adult Rats

Thyroid Hormones: Their Role in Testicular Steroidogenesis

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