Effect of testosterone propionate treatment on thyrotropin secretion of young and old rats in vitro

Borges, Patricia P.; Curty, F. H.; Pazos‐Moura, Carmen C.; Moura, E.G.

doi:10.1016/s0024-3205(98)00175-1

Cited by 21 publications

(21 citation statements)

References 22 publications

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“…Therefore, it was speculated that a difference in serum TSH between males and females is, at least, partly due to change in DIO1 enzyme activity. It is well known that castration of young adult males significantly reduces circulating levels of TSH (Christianson et al 1981, Bagchi et al 1984, Borges et al 1998, Marassi et al 2007). However, in line with the results of this study, those who examined the effects of castration in older males demonstrated no effect on TSH level in circulation (Bagchi et al 1984, Chen 1984.…”

Section: Discussionmentioning

confidence: 99%

Orchidectomy of middle-aged rats decreases liver deiodinase 1 and pituitary deiodinase 2 activity

Šošić‐Jurjević

Filipović

Renko

et al. 2012

Journal of Endocrinology

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Endogenous androgens are involved in regulation of thyroid function and metabolism of thyroid hormones. As serum testosterone level progressively declines with age, this regulation may change. We tested how androgen deprivation, achieved by orchidectomy, affects thyroid homeostasis in middle-aged rats. Fifteen-month-old Wistar rats were orchidectomized (Orx) or sham-operated under ketamine anesthesia (15 mg/kg body weight). Five weeks after the surgery, animals were decapitated. Thyroids were used for histomorphometric and ultrastructural examinations and together with livers and pituitaries for real-time quantitative PCR and deiodinase (DIO) activity measurements. Serum testosterone, TSH, L-thyroxine (T 4 ), and cholesterol (Chol) levels were determined. As expected, middle-aged control rats had lower (P!0 . 05) testosterone and T 4 compared with 3-month-old males. In the Orx middle-aged group, we detected diminished serum testosterone (P!0 . 05), no change in TSH and T 4 levels, and higher Chol level (P!0 . 05), in comparison with age-matched controls. Histomorphometric analysis of thyroid tissue revealed decreased relative volume densities of follicles and colloid (P!0 . 05). Relevant gene expressions and DIO1 enzyme activity were not changed in the thyroids of Orx rats. Liver Dio1 gene expression and DIO1 activity were decreased (P!0 . 05) in comparison with the control values. Pituitary levels of TSHb, Dio1, and Dio2 mRNAs did not change, while DIO2 activity decreased (P!0 . 05). In conclusion, orchidectomy of middle-aged rats affected thyroid structure with no effect on serum T 4 and TSH. However, decreased liver DIO1 and pituitary DIO2 enzyme activities indicate compensatoryadaptive changes in local T 3 production.

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Section: Discussionmentioning

confidence: 99%

Orchidectomy of middle-aged rats decreases liver deiodinase 1 and pituitary deiodinase 2 activity

Šošić‐Jurjević

Filipović

Renko

et al. 2012

Journal of Endocrinology

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“…In our study, the same period of leptin treatment in male rats did not change gland weight, neither serum thyroid hormones nor TSH. Some authors observed the sex steroid effects upon hypothalamic-pituitary-thyroid axis (Mason et al, 1996;Lisboa et al, 1997;Moreira et al, 1997;Borges et al, 1998;Correa da Costa et al, 2001;Lisboa et al, 2001;Moura et al, 2001;Moreira et al, 2005). Then, it is possible that gender influences leptin action upon thyroid function.…”

Section: Discussionmentioning

confidence: 99%

Acute and chronic leptin effect upon in vivo and in vitro rat thyroid iodide uptake

et al. 2007

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“…Progesterone (Pg) has been reported to have no effect (3) or to stimulate (4) TSH secretion, although there are very few reports on this subject. Testosterone seems to be a stimulatory factor of TSH secretion in castrated male rats (5). Many reports suggest that an excess of glucocorticoids decreases TSH release (6), although their physiological role in TSH regulation is still unclear.…”

Section: Introductionmentioning

confidence: 98%

Effect of medroxyprogesterone acetate on thyrotropin secretion in adult and old female rats

Moreira

Borges

Lisboa

et al. 2000

Braz J Med Biol Res

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Steroid hormones have been implicated in the modulation of TSH secretion; however, there are few and controversial data regarding the effect of progesterone (Pg) on TSH secretion. Medroxyprogesterone acetate (MPA) is a synthetic a-hydroxyprogesterone analog that has been extensively employed in therapeutics for its Pg-like actions, but that also has some glucocorticoid and androgen activity. Both hormones have been shown to interfere with TSH secretion. The objective of the present study was to investigate the effects of MPA or Pg administration to ovariectomized (OVX) rats on in vivo and in vitro TSH release and pituitary TSH content. The treatment of adult OVX rats with MPA (0.25 mg/100 g body weight, sc, daily for 9 days) induced a significant (P<0.05) increase in the pituitary TSH content, which was not observed when the same treatment was used with a 10 times higher MPA dose or with Pg doses similar to those of MPA. Serum TSH was similar for all groups. MPA administered to OVX rats at the lower dose also had a stimulatory effect on the in vitro basal and TRH-induced TSH release. The in vitro basal and TRH-stimulated TSH release was not significantly affected by Pg treatment. Conversely, MPA had no effect on old OVX rats. However, in these old rats, ovariectomy alone significantly reduced (P<0.05) basal and TRH-stimulated TSH release in vitro, as well as pituitary TSH content. The results suggest that in adult, but not in old OVX rats, MPA but not Pg has a stimulatory effect on TSH stores and on the response to TRH in vitro.

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Effect of testosterone propionate treatment on thyrotropin secretion of young and old rats in vitro

Cited by 21 publications

References 22 publications

Orchidectomy of middle-aged rats decreases liver deiodinase 1 and pituitary deiodinase 2 activity

Orchidectomy of middle-aged rats decreases liver deiodinase 1 and pituitary deiodinase 2 activity

Acute and chronic leptin effect upon in vivo and in vitro rat thyroid iodide uptake

Effect of medroxyprogesterone acetate on thyrotropin secretion in adult and old female rats

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