Effects of ovariectomy and chronic estradiol administration on pituitary–thyroid axis in adult rats

Šošić‐Jurjević, Branka; Filipović, Branko; Milošević, Verica; Nestorović, Nataša; Negić, Nataša; Sekulić, Milka

doi:10.1016/j.lfs.2006.03.001

Cited by 19 publications

(16 citation statements)

References 28 publications

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“…Moreover, another reason that also probably prevented us from identifying significant menstrual cycle-related variations in thyroid-related hormone levels is that we happened to compare thyroid-related hormone levels between the two phases under similar estrogen concentrations. It has been reported that thyroid hormone levels fluctuate in relation to circulating estrogen levels during the menstrual cycle (5,16) and that estrogen may influence thyroid-related hormone levels via changing T 4 -binding globin levels and the sensitivity of TSH cells to negative feedback regulation of thyroid hormones (1,2,44,59). Therefore, the absence of changed thyroid-related hormone levels during the menstrual cycle in our study is not inconsistent with the concept that the menstrual cycle can influence thyroid function.…”

Section: Correlations Between Nonlinear and Linear Hrv Measuressupporting

confidence: 50%

Influence of the menstrual cycle on nonlinear properties of heart rate variability in young women

Bai

Li²,

Zhou³

et al. 2009

American Journal of Physiology-Heart and Circulatory Physiology

148

108

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This study was designed to assess the changes in nonlinear properties of heart rate (HR) variability (HRV) during the menstrual cycle by means of complexity measures, including sample entropy (SampEn) and correlation dimension (CD), and explore probable physiological interpretations for them. In 16 healthy women (mean age: 23.8 +/- 2.7 yr), complexity measures along with the spectral components of HRV (sympathovagal markers) were analyzed over 1,500 R-R intervals recorded during both the follicular phase (day 11.9 +/- 1.4) and the luteal phase (day 22.0 +/- 1.4) of each woman's menstrual cycle. Simultaneously, serum ovarian hormone (estradiol-17 and progesterone) and thyroid-related hormone [free triiodothyronine, free thyroxine (T(4)), and thyroid-stimulating hormone] concentrations were measured. With regard to HRV measures, SampEn, CD, and high-frequency (HF) components decreased from the follicular phase to the luteal phase, whereas normalized low-frequency (LF) components and the LF-to-HF ratio as well as resting HR increased. In regard to hormone levels, whereas progesterone was increased, the other hormone concentrations were unchanged. Furthermore, across the menstrual cycle, both SampEn and CD were well correlated with the spectral indexes and free T(4) concentrations, and SampEn also showed significant correlations with the ratio of estradiol-17 to progesterone concentrations. These results suggest that the nonlinear properties in HRV are altered during the regular menstrual cycle and that the autonomic nervous system, ovarian hormone balance, and free T(4) may be involved in nonlinear HR control in healthy women. All of these factors may enrich the physiological meanings of complexity measures.

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Section: Correlations Between Nonlinear and Linear Hrv Measuressupporting

confidence: 50%

Influence of the menstrual cycle on nonlinear properties of heart rate variability in young women

Bai

Li²,

Zhou³

et al. 2009

American Journal of Physiology-Heart and Circulatory Physiology

148

108

View full text Add to dashboard Cite

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“…According to the fact that the tissue concentrations of proteins do not causally relate with their secretion and the mRNA levels of secretory proteins as the indicator of alterations in the biosynthesis may serve as a more reliable indicator of long-term change in their secretion and release [15,35], therefore it is most likely that upon the short-term administration to adult male rats equol may inhibit pituitary thyrotrophs via interfering with TSH β-subunit gene expression only at the step of transcription but not the posttranslational modifications in such a way that low peripheral thyroid hormone levels cannot be compensated by the increase in the biosynthesis and secretion of TSH. There are also previous descriptions of this effect in adult rats upon the treatments with estradiol [38] as well as octylmethoxycinnamate, which is an endocrine disruptor [13]. In addition, the reductions in circulating total T4 and T3 concentrations were observed along with the increase in relative liver weights in the rats treated with flutamide.…”

Section: Discussionmentioning

confidence: 70%

The influence of equol on the hypothalamic–pituitary–thyroid axis and hepatic lipid metabolic parameters in adult male rats

2015

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“…This pattern was previously described as normal histological features in rat thyroid and not in humans [37,38] . The peripheral follicles mainly serve as a pool of old hormone, whereas the smaller, centrally distributed ones are responsible for thyroid hormone secretion [39] . Therefore, central follicles were chosen for morphometric measurements.…”

Section: Discussionmentioning

confidence: 99%

Histological study on the possible protective effect of curcumin on potassium dichromate induced hypothyroidism in adult male albino rats

Aboul-Fotouh

El-Nour

Farag

et al. 2018

Egyptian Journal of Histology

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Introduction: Potassium dichromate, a widely used heavy metal in several industries induces hypofunction and tissue insult of the thyroid gland via oxidative stress. Curcumin; is a natural commonly used spice has a strong anti-inflammatory and antioxidant properties. Aim of the work: To investigate the possible protective effect of curcumin on the hypothyroidism induced by potassium dichromate in albino rats. Materials and Methods: Thirty-five adult male albino rats were divided into five groups, 15 rats in group I (control) and 5 rats in each of group II, III, IV and V. Group II (curcumin group) received curcumin orally (100 mg /kg/bw) daily for 4 weeks. Group III (potassium dichromate induced hypothyroidism) received i.p injection of potassium dichromate (2 mg/kg/ bw) daily for 2 weeks. Group IV (recovery group) received potassium dichromate as group III then left untreated for another 2 weeks. Group V(curcumin and potassium dichromate group) received curcumin concomitant with potassium dichromate as in groups II and III, respectively daily for 2 weeks and only curcumin was continued for another 2 weeks. T3, T4 and TSH were assessed. Thyroid sections were subjected to toluidine blue, H&E, PAS and PCNA immunohistochemical stains. Morphometric and statistical studies were done. Results: Thyroid tissue insult and hypofunction with significantly decreased T3, T4 and increased TSH were detected in group III. Additionally, there was a significant increase in the mean values of follicular cell height, follicular diameter, mean number of PCNA positive nuclei and a significant decrease in the mean value of area percent of colloid versus group I, II and V with non-significant differences versus group IV. In group V, there was an obvious serological and histological improvement compared to group III and IV. Conclusion: Curcumin had protective effect against hypothyroidism and thyroid tissue damage induced by potassium dichromate.

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Effects of ovariectomy and chronic estradiol administration on pituitary–thyroid axis in adult rats

Cited by 19 publications

References 28 publications

Influence of the menstrual cycle on nonlinear properties of heart rate variability in young women

Influence of the menstrual cycle on nonlinear properties of heart rate variability in young women

The influence of equol on the hypothalamic–pituitary–thyroid axis and hepatic lipid metabolic parameters in adult male rats

Histological study on the possible protective effect of curcumin on potassium dichromate induced hypothyroidism in adult male albino rats

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