Neuronal organelles and nuclear pores of hypothalamic ventromedial neurons are sexually dimorphic and change during the estrus cycle in the rat

• Type: Article in International Scientific Journal
• Date: 2005

Authors

Sa, SI (Author) Other; Madeira, MD (Author) FMUP

Journal

Title: Neuroscience

Vol. 133

Pages: 919-924

ISSN: 0306-4522

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 16 Citations

Scopus - 16 Citations

Scientific classification

FOS: Medical and Health sciences > Basic medicine

Other information

Authenticus ID: P-000-6BA

DOI: 10.1016/j.neuroscience.2005.02.033

Abstract (EN): Neurons in the ventrolateral division of the hypothalamic ventromedial nucleus (VMNvI) become hypertrophied when exposed to high estrogen levels, an effect that has been observed after estrogen treatment of ovariectomized rats as well as during the proestrus stage of the ovarian cycle. In an attempt to examine whether the neuronal hypertrophy noticed in these conditions reflects metabolic activation of the neurons we have examined, using quantitative methods, the cytoplasmic organelles involved in protein synthesis and the nuclear pores of VMNvI neurons from females on proestrus, when estrogen levels are high, and on diestrus, when estrogen levels are low. Because VMNvI neurons are sexually dimorphic with respect to their size we have performed, in parallel, similar analyses in neurons from age-matched male rats. Our results show that the volume and the surface area of the rough endoplasmic reticulum (RER) and Golgi apparatus are increased at proestrus. They also show that the density of nuclear pores is greater in males than in females whereas the volume and the surface area of the RER and Golgi apparatus are sexually dimorphic only at specific phases of the ovarian cycle: the male-female differences are notorious in the RER when females are on diestrus and in the Golgi apparatus when they are on proestrus. Given that the size of the RER and of the Golgi apparatus correlates with the level of neuronal protein synthesis, data obtained in this study suggest that the sex-related differences and the estrus cycle variations in neuronal size reflect corresponding differences and fluctuations in the metabolic activity of VMNvI neurons.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 6