Serum hormones and seminal parameters in males with thyroid disturbance

25-Hydroxy cholecalciferol, anti-Müllerian hormone, and thyroid profiles among infertile men

BACKGROUND AND AIM

We examined the relationship among vit.D₃, AMH, FT3, FT4, and TSH, in addition to the serum levels of reproductive hormones (FSH, LH, prolactin, and free testosterone), in oligoasthenoteratozoospermia and azoospermia patients in a cohort of infertile men from Egypt to establish a clinical marker/cause-effect relationship.

METHODS

This cross-sectional cohort study was carried out on 301 men (105 males with oligoasthenoteratozoospermia and 96 males with azoospermia), in addition to 100 controls. Measurements of serum vit.D₃, AMH, FT3, FT4, and TSH levels, in addition to reproductive hormone assays, were performed on all included subjects, using ELISA kits.

RESULTS

Overall, results showed significantly lower serum levels of vit.D₃ in infertile men than in the controls, with a greater decrease observed in men with azoospermia than in oligoasthenoteratozoospermia patients, (p < .05 for all). Significantly higher serum TSH and FSH levels and significantly lower serum free testosterone levels were observed in males with azoospermia than in males with oligoasthenoteratozoospermia and the controls (p < .05 for both). There were no significant differences between the studied groups in terms of AMH, FT3 or FT4 levels. LH levels were negatively correlated with TSH levels and positively correlated with AMH levels among men with oligoasthenoteratozoospermia, while among men with azoospermia, LH levels were positively correlated with vit.D₃ levels (p < .05 for all).

CONCLUSION

Decreased Vit.D₃ could play a role in male infertility, in addition to abnormal thyroid function, which needs further investigation.

Adverse effects of neonatal exposure to 3,3',4,4',5,5'-hexachlorobiphenyl on hormone levels and testicular function in male Sprague-Dawley rats

In this study, we investigated the time-course changes of hormone levels and sperm numbers in male Sprague-Dawley (SD) rats after neonatal exposure to 3,3',4,4',5,5'-hexachlorobiphenyl (PCB169). Neonatal rats were given (through oral gavages) doses of 0, 0.025, 0.25, or 0.5 mg/kg-day of PCB169 in corn oil from postnatal day 1 (PND1) to PND7. The rats were sacrificed at PND8, PND21, and PND90. PCB169 exposure was confirmed by the marked induction of liver CYP1A1 mRNA expression at these three time points. The testicular daily sperm production and the sperm counts of the epididymis cauda significantly decreased at PND90 compared to that of control. Although reductions in serum thyroxine and triiodothyronine levels occurred at all these three time points and at both PND21 and PND90, respectively, the mRNA expression of testicular thyroid hormone receptor α1 was suppressed significantly only at PND8. The serum and testicular testosterone (T) levels declined markedly at PND90 compared to the controls, but there was no effect at PND21. The mRNA expression of testicular steroidogenic factor 1 was inhibited markedly at the three time points, whereas those of StAR, P450c17, P450scc, and 3β-HSD were suppressed significantly only at PND90 relative to the controls. PCB169 treatment had no effects on pituitary follicle-stimulating hormone and luteinizing hormone levels and on their receptors' expression in the testes. These results indicate that neonatal exposure to PCB169 damages hormone levels and testicular function in the long-term, resulting in persistent hypothyroidism and decreases in adult T levels and sperm counts.

Poly(ADP-ribosyl)ation of proteins and germ cell development in hyperthyroid rat testes

The effect of increased serum levels of thyroid hormone (triiodothyronine, T3) on young rat testis spermatogenesis was studied by analysing molecular and morphological parameters. Hyperthyroidism was induced by either T3-treatment or 2- and 10-day cold exposure. The poly(ADP-ribosyl)ation of proteins catalysed by poly(ADP-ribose) polymerase, which is particularly active at specific stages of rat spermatogenesis, was analysed as molecular index of DNA damage and cell stress. Poly(ADP-ribose) polymerase activity rose after both T3-treatment and 2- and 10-day cold exposure, with a trend of 10-day cold-exposed rats towards control values. In all hyperthyroid rats poly(ADP-ribose) turnover, as a contribution of both poly(ADP-ribose) polymerase and poly(ADP-ribose) glycohydrolase), was enhanced with respect to euthyroid animals. Poly(ADP-ribosyl)ation of proteins occurred with long and branched polymers suggesting an increased involvement of the modification system in DNA repair. Morphological changes of germ tissue were observed in hyperthyroid rats, mainly a high reduction of mature cells in the seminiferous tubule, and evidence of germ cell apoptosis was obtained by TUNEL method. In control animals germ cell apoptosis was within physiological levels. Conversely, in hyperthyroid rats a dramatic increase in the number of TUNEL-positive cells (some spermatogonia and numerous primary spermatocytes) was found, even though the increase was lower in 10-day than in 2-day cold-exposed animals.

Thiourea-induced thyroid hormone depletion impairs testicular recrudescence in the air-breathing catfish, Clarias gariepinus

We used thiourea-induced thyroid hormone depletion as a strategy to understand the influence of thyroid hormones on testicular recrudescence of the air-breathing catfish, Clarias gariepinus. Treatment with 0.03% thiourea via immersion for 21 days induced hypothyroidism (thyroid hormone depletion) as evidenced by significantly reduced serum T(3) levels. Thiourea-treated males had narrowed seminiferous lobules with fewer spermatozoa in testis, very little or no secretory fluid, reduced protein and sialic acid levels in seminal vesicles when compared to controls. The histological changes were accompanied by reduction in serum and tissue levels of testosterone (T) and 11-ketotestosterone (11-KT), a potent male specific androgen in fish. Qualitative changes in the localization of catfish gonadotropin-releasing hormone (cfGnRH) and luteinizing hormone (LH, heterologous system) revealed a reduction in the distribution of immunoreactive neuronal cells and fibers in thyroid depleted fish. Interestingly, thiourea-withdrawal group showed physiological and histological signs of recovery after 21 days such as reappearance of spermatozoa and partial restoration of 11-KT and T levels. These data demonstrate that thyroid hormones play a significant role in testicular function of catfish. The mechanism of action includes modulating sex steroids either directly or through the hypothalamo (GnRH)-hypophyseal (LH) axis.

Thyroid hormones: their role in testicular steroidogenesis

Thyroid hormones are important for growth and development of many tissues. Altered thyroid hormone status causes testicular abnormalities. For instance, juvenile hypothyroidism/neonatal transient hypothyroidism induces macroorchidism, increases testicular cell number (Sertoli, Leydig, and germ cells) and daily sperm production. Triiodothyronine (T3) receptors have been identified in sperm, developing germ cells, Sertoli, Leydig, and peritubular cells. T3 stimulates Sertoli cell lactate secretion as well as mRNA expression of inhibin-alpha, androgen receptor, IGF-I, and IGFBP-4. It also inhibits Sertoli cell mRNA expression of Müllerian inhibiting substance (MIS), aromatase, estradiol receptor, and androgen binding protein (ABP) and ABP secretion. T3 directly increases Leydig cell LH receptor numbers and mRNA levels of steroidogenic enzymes and steroidogenic acute regulatory protein. It stimulates basal and LH-induced secretion of progesterone, testosterone, and estradiol by Leydig cells. Steroidogenic factor-1 acts as a mediator for T3-induced Leydig cell steroidogenesis. Although the role of T3 on sperm, germ, and peritubular cells has not yet been completely studied, it is clear that T3 directly regulates Sertoli and Leydig cell functions. Further studies are required to elucidate the direct effect of T3 on sperm, germ, and peritubular cells.

Hormonal profile of infertile Makkans

Male factor infertility, being a complex and heterogeneous disorder, precludes any reliance on a single laboratory test and requires broad spectrum assessment. Sociobiological factors also influence the parameters. In this context we examined serum concentrations of nine hormones in infertile and fertile male Makkans. Infertility was implicated in 21% of the population with correlated abnormalities of gonadotrophins, thyroid, thyroid stimulating hormone (TSH), and testosterone. Hypothyroidism was established in 35% and hyperthyroidism in 14% of the infertile population, where 28% of thyroid abnormality constituted an independent infertile group. Hyperprolactinaemia associated with low levels of luteinizing hormone (LH) and testosterone signifies a cluster of 28%, while 14% of testosterone deficiency alone was causal for infertility. However, infertility in 9% of the patients examined might have been psychogenic in nature. We present a responder panel based on cluster analysis.

Routine hormone load tests are unnecessary in infertile men

A sample of 225 men examined at the Infertility Service Unit of this hospital had spermiograms, standardized in accordance with WHO guide lines, and a hormone stimulation test with injection of gonadotropin releasing hormone, thyrotropin releasing hormone, and ACTH. The serum concentrations of the following hormones were assessed: follicle stimulating hormone (FSH), luteinizing hormone (LH), prolactin, oestradiol (E), thyroid stimulating hormone, cortisol, 21-desoxycortisol, 17-hydroxypregnenolone, 17-hydroxyprogesterone, dehydroepiandrosterone, dehydroepiandrosteronesulphate, androstenedione, testosterone (T), and dihydrotestosterone. The results of the spermiograms were found to be related to the concentrations of the following hormones: FSH, LH, T, and E. Thyroid and adrenal function in men without signs of endocrinological diseases failed to influence spermatic parameters.

Hormone load tests in infertile male patients

The recognition that discreet hormonal abnormalities may cause ovulation disorders in women suggested that the male partner of infertile women might also suffer from unrecognized hormonal dysfunction amendable to substitution therapy. We obtained a combined stimulation test with gonadotropin-releasing hormone (GnRH), thyreotropin-releasing hormone (TRH), and ACTH in 225 males with childless spouses, when the couple sought to have children for at least one year. The following hormone levels were determined: estradiol (E), thyroid-stimulating hormone (TSH), prolactin, testosterone (T), dihydrotestosterone (DHT), androstenedione(A), 17-OH-pregnenolone (17-OH-Preg), 17-OH-progesterone (17-OHP), dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulfate (DHEAS), cortisone (F), and 21-desoxycortisone (21DF). Basal and stimulated, and adrenal-testicular steroids with and without ACTH stimulation failed to demonstrate a relevant relationship to semen parameters. Gonadotropin levels had a significant negative correlation to all important semen parameters (testicular volume, sperm count, motility, morphology, and vitality) and were positively correlated to spermiogenetic defects. Stimulated LH values were more clearly associated with spermiogenetic defects than basal LH. Nonetheless, basal FSH concentrations were more informative than LH. Stimulated prolactin values were positively correlated with both gonadotropin and with sperm morphology. E concentrations had a significant positive correlation with both basal and poststimulation DHEAS values, and showed a highly negative correlation with sperm count, morphology, and vitality. In comparison, good sperm parameters were associated with high poststimulation T concentrations. The results of this study suggest that basal FSH and E concentrations, as well as the stimulated LH, T, and prolactin determinations, should be included in the evaluation of male sterility.

Pituitary-thyroid relationships in hypothyroidism

The pituitary gland is undoubtedly a target for thyroid hormone. It is the tissue with the highest density of T3 receptors and contains Type II T4 5' deiodinase which are involved in the secretion of TSH and other pituitary hormones. In the case of TSH, this knowledge has resulted in a better understanding of a number of conditions such as the adaptation to reduced thyroid reserve, and in an improvement in the way we treat hypothyroidism. But the pituitary being a target tissue for thyroid hormones has additional consequences. A direct effect of T3 on various secretions of the gland has been documented, and in the case of other pituitary hormones, directly or indirectly, thyroid hormone has some effect. T3 has a broad spectrum of metabolic and physiological effects that may, by themselves, account for a large proportion of the variability of the clinical presentation of hypothyroidism. The multiplicity of pituitary hormones and the multiplicative action of these various hormones through their target glands make the pituitary gland another key element in the variability of clinical manifestations of hypothyroidism. While this variability poses a diagnostic challenge in that hypothyroidism should be considered in a large number of conditions, the abnormalities resulting from the lack of thyroid hormone in the pituitary are equally challenging from a therapeutic point of view, since they respond promptly to the correction of the hypothyroidism. We should try to identify and treat those that are both life-threatening and not corrected rapidly by the administration of thyroid hormone.