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Determination of Reproductive Competence by Confirming Pubertal Onset and Performing a Fertility Assay in Mice and Rats
Published on: October 13, 2018
Catecholamines in hypothalamus, ovaries and uteri of rats with precocious puberty
O K Ivanisević-Milovanović1, V Pantic, M Demajo
1Laboratory for Molecular Biology and Endocrinology, Institute of Nuclear Sciences, Beograd, Yugoslavia.
Insights
Hypothalamic lesions in female rats induced precocious puberty, altering catecholamine levels in reproductive organs and the hypothalamus. These changes suggest a role for catecholamines in regulating the timing of puberty onset.
Area of Science:
- Neuroendocrinology
- Reproductive Biology
Background:
- The precise mechanisms regulating the onset of puberty are complex and not fully understood.
- Catecholamines are neurotransmitters implicated in various physiological processes, including reproductive function.
Purpose of the Study:
- To investigate the role of catecholamines in the regulation of puberty.
- To examine hypothalamic, ovarian, and uterine catecholamine concentrations in female rats with experimentally induced precocious puberty.
Main Methods:
- Female rats received hypothalamic lesions on the day of birth to induce precocious puberty.
- Catecholamine concentrations (norepinephrine, epinephrine, dopamine) were measured in the hypothalamus, ovaries, and uterus.
- Data were compared between lesioned rats (at precocious puberty), pubertal controls, and age-matched infantile controls.
Main Results:
- Animals with hypothalamic lesions exhibited precocious vaginal opening (around 25.7 days) compared to controls (around 40.1 days).
- Ovarian and uterine mass were significantly lower in lesioned rats compared to pubertal controls.
- Norepinephrine and epinephrine levels were elevated in the ovaries and uteri of lesioned and infantile rats compared to pubertal controls.
- Hypothalamic dopamine and norepinephrine levels were higher in lesioned and pubertal rats than in infantile controls.
Conclusions:
- Early hypothalamic damage alters catecholamine levels in reproductive organs and the hypothalamus.
- These findings suggest that catecholamines play a significant role in the neuroendocrine regulation of puberty onset.
Abstract:
The concentration of catecholamines in the hypothalamus and reproductive organs of rats with hypothalamic lesions placed on the day of birth was investigated. In an attempt to contribute to the discussion concerning the role of catecholamines in regulation of puberty, the aim of this study was to examine the content of hypothalamic, ovarian and uterine catecholamines in female rats with precocious vaginal opening. The animals were sacrificed on the day of precocious puberty, which occurred at the age of 25.71 +/- 0.98 days. The data obtained were compared with intact (pubertal) controls obtained on the day of vaginal opening (40.13 +/- 1.35 days) as well as in infantile intact controls of corresponding age of the lesioned animals. In the ovaries of both animals (i.e. lesioned and sacrificed on day of vaginal opening and the infantile controls of corresponding age), small and medium sized follicles were present. Ruptured follicles were evident only in the pubertal controls. The mass of ovaries and uteri from lesioned rats was also significantly lower than in the pubertal controls. Concentrations of norepinephrine in both ovaries and uteri on the day of vaginal opening of the animals with posterior hypothalamic lesions and of infantile controls, was significantly higher than in pubertal controls on the day of vaginal opening. Epinephrine was significantly higher in the uterine tissues of lesioned and infantile controls as compared to pubertal animals. The levels of dopamine and norepinephrine in the hypothalamus of lesioned and pubertal controls on the day of vaginal opening were significantly higher than in infantile controls.(ABSTRACT TRUNCATED AT 250 WORDS)
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