Regulation of adenohypophyseal messenger RNAs in female rats by age, hypothyroidism, estradiol and neonatal androgenization

Jonassen, Julie A.; Mullikin‐Kilpatrick, Debra; Hoogasian, Janet; Benoit, Stephen E.; Leeman, Susan E.

doi:10.1016/0303-7207(92)90071-d

Cited by 12 publications

(7 citation statements)

References 47 publications

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“…We further reported that hyperthyroidism and hypothyroidism diminished serum E2 concentrations in immature rats. Similarly, it was previously reported that serum E2 level decreased in hypothyroid immature rats [21]. The results of the current study clearly showed cell-specific expression of TRa1 in the immature rat ovary.…”

Section: Discussionsupporting

confidence: 85%

Nitric oxide and thyroid hormone receptor alpha 1 contribute to ovarian follicular development in immature hyper- and hypo-thyroid rats

Zheng

Sulieman

et al. 2015

Reproductive Biology

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Section: Discussionsupporting

confidence: 85%

Nitric oxide and thyroid hormone receptor alpha 1 contribute to ovarian follicular development in immature hyper- and hypo-thyroid rats

Zheng

Sulieman

et al. 2015

Reproductive Biology

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“…This possibility could be tested experimentally. Estradiol treatment of normal female rats had no influence on TSH ß mRNA abundance (11,12), but was able to reduce the effect of hypothyroidism (11,12) and to amplify the T3-induced suppression of TSH ß mRNA in hypothyroid rats (12). These findings suggest that estradiol might have a negative influence on ß TSH gene expression.…”

Section: Discussionmentioning

confidence: 63%

“…In normal female rats, estradiol treatment decreased the pituitary hormonal content (8)(9)(10) without changing serum TSH (8,9). It was also reported that estradiol augments the suppressive effects of thyroid hormones on TSH synthesis (11,12) and secretion (12). Early studies (13,14) in which bioassays were employed to quantify TSH have suggested that estradiol has a biphasic effect on plasma and pituitary TSH, being stimulatory at lower doses and inhibitory at higher doses.…”

Section: Introductionmentioning

confidence: 99%

“…Early studies (13,14) in which bioassays were employed to quantify TSH have suggested that estradiol has a biphasic effect on plasma and pituitary TSH, being stimulatory at lower doses and inhibitory at higher doses. In more recent years, as reviewed previously (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12), both positive and negative modulatory effects of estrogen have been reported. However, the studies did not focus on dose-related effects, a fact that may partially explain the conflicting results.…”

Section: Introductionmentioning

confidence: 99%

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Dose-dependent effects of 17-ß-estradiol on pituitary thyrotropin content and secretion in vitro

Moreira

Lisboa

Curty

et al. 1997

Braz J Med Biol Res

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We studied the basal and thyrotropin-releasing hormone (TRH) (50 nM) induced thyrotropin (TSH) release in isolated hemipituitaries of ovariectomized rats treated with near-physiological or high doses of 17-ß-estradiol benzoate (EB; sc, daily for 10 days) or with vehicle (untreated control rats, OVX). One group was sham-operated (normal control). The anterior pituitary glands were incubated in Krebs-Ringer bicarbonate medium, pH 7.4, at 37 o C in an atmosphere of 95% O 2 /5% CO 2 . Medium and pituitary TSH was measured by specific RIA (NIDDK-RP-3). Ovariectomy induced a decrease (P<0.05) in basal TSH release (normal control = 44.1 ± 7.2; OVX = 14.7 ± 3.0 ng/ml) and tended to reduce TRH-stimulated TSH release (normal control = 33.0 ± 8.1; OVX = 16.6 ± 2.4 ng/ml). The lowest dose of EB (0.7 µg/ 100 g body weight) did not reverse this alteration, but markedly increased the pituitary TSH content (0.6 ± 0.06 µg/hemipituitary; P<0.05) above that of OVX (0.4 ± 0.03 µg/hemipituitary) and normal rats (0.46 ± 0.03 µg/hemipituitary). The intermediate EB dose (1.4 µg/ 100 g body weight) induced a nonsignificant tendency to a higher TSH response to TRH compared to OVX and a lower response compared to normal rats. Conversely, in the rats treated with the highest dose (14 µg/100 g body weight), serum 17-ß-estradiol was 17 times higher than normal, and the basal and TRH-stimulated TSH release, as well as the pituitary TSH content, was significantly (P<0.05) reduced compared to normal rats and tended to be even lower than the values observed for the vehicle-treated OVX group, suggesting an inhibitory effect of hyperestrogenism. In conclusion, while reinforcing the concept of a positive physiological regulatory role of estradiol on the TSH response to TRH and on the pituitary stores of the hormone, the present results suggest an inhibitory effect of high levels of estrogen on these responses.

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“…In a previous study we demonstrated that neonatal androgenisation profoundly reduced pituitary leptin mRNA levels [23]. Exposure of neonatal female rodents to testosterone reliably induces hormonal changes in hypothalamus [31, 32]and pituitary gene expression [33, 34]. It remains possible that pituitary resistin mRNA in male mice is testosterone dependent.…”

Section: Discussionmentioning

confidence: 99%

Pituitary Resistin Gene Expression: Effects of Age, Gender and Obesity

Morash¹,

Ur²,

Wiesner³

et al. 2004

Neuroendocrinology

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Resistin is a new adipocytokine which is expressed in rat, mouse and possibly human adipose tissue. Its putative role as a mediator of insulin resistance is controversial. We hypothesized that resistin, like leptin, would have multiple roles in non-adipose tissues and we reported that resistin is expressed in mouse brain and pituitary. Moreover, resistin expression in female mouse pituitary is developmentally regulated and maximal expression occurs peripubertally. Although the role of endogenous resistin in mouse brain and pituitary has not been determined, our data suggest that resistin could be important in the postnatal maturation of the hypothalamic-pituitary system. In the present study we compared the ontogeny of resistin gene expression in the pituitary of male and female mice using semi-quantitative RT-PCR analysis. We show that resistin expression is developmentally regulated in the pituitary of male and female CD1 mice. However, significant gender differences were evident (male > female at postnatal day 28 and 42) and this was not modified by neonatal treatment of female pups with testosterone. Since resistin expression in adipose tissue is also influenced by obesity, we evaluated resistin expression in fat, brain and pituitary of the obese ob/ob mouse. Resistin mRNA was significantly increased in both visceral and subcutaneous adipose depots in postnatal day 28 ob/ob mice compared to controls, but pituitary resistin expression was significantly reduced. In contrast to the prepubertal levels, and in agreement with other reports, adipose resistin expression was reduced in adult ob/ob mice. In a third set of experiments we examined the influence of food deprivation on pituitary and fat resistin mRNA. Resistin gene expression was severely down-regulated by a 24-hour fast in adipose and pituitary tissue but not in hypothalamus. In conclusion, pituitary resistin expression is age- and gender-dependent. In ob/ob mice, and in fasted mice, resistin is regulated in a tissue-specific manner. Thus in visceral fat obesity increases but starvation decreases resistin mRNA. In contrast, pituitary levels are decreased in the presence of both high (ob/ob) and low (fasting) adipose stores. Further studies are required to define the unexpected hormonal regulation of resistin gene expression in the pituitary.

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Regulation of adenohypophyseal messenger RNAs in female rats by age, hypothyroidism, estradiol and neonatal androgenization

Cited by 12 publications

References 47 publications

Nitric oxide and thyroid hormone receptor alpha 1 contribute to ovarian follicular development in immature hyper- and hypo-thyroid rats

Nitric oxide and thyroid hormone receptor alpha 1 contribute to ovarian follicular development in immature hyper- and hypo-thyroid rats

Dose-dependent effects of 17-ß-estradiol on pituitary thyrotropin content and secretion in vitro

Pituitary Resistin Gene Expression: Effects of Age, Gender and Obesity

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