Effects of gonadotropins on testis cell subpopulations of newly hatched chicks treated during embryonic development.

The aim of the present study was to evaluate histological and stereological changes, as well as the variations in the number and size of cells from diverse cell subpopulations in testes of newly hatched chicks treated with follicle stimulating hormone (FSH) and luteinizing hormone (LH) during embryonic development. Stereological results indicated that in FSH-treated chicks total volume of the tubular compartment constitutes most of the testis. In contrast, the total volume of interstitial tissue constitutes most of the testis of LH-treated chicks.

Changes in the immunohistochemical localization of estrogen receptor alpha and in the stereological parameters of the testes of mature and aged chickens (Gallus domesticus).

The aim of this study was to detect through immunohistochemistry the presence of the estrogen receptor alpha (ER-α) in different cell subpopulations, as well as to evaluate the histological and stereological changes of the testes of mature and aged chickens. Histological results demonstrated several changes in the tubular compartment and interstitial tissue in aged chicken testis as compared to mature chicken testis. Stereological results revealed that the mature chicken testis increases in volume as well as the total volume of the tubular compartment, whereas the total volume of the interstitial tissue and the total volume of Leydig cells diminishes as compared to aged chicken testis.

Expression of sex hormone receptors in the brain of male and female newly hatched chicks.

Chromosomal sex and steroid hormones play a determining role in brain sexual differentiation during chick embryonic development. Hormone effects on the brain are associated with the expression pattern of their intracellular receptors, which is sexually dimorphic in many species. We determined by Western blot the content of progesterone, estrogen, and androgen receptors (PR-A and PR-B, ERα, and AR, respectively) in the cortex, cerebellum, tectum, and hypothalamus of female and male newly hatched chicks.

Changes in progesterone receptor isoforms expression and in the morphology of the oviduct magnum of mature laying and aged nonlaying hens.

The aim of this study was to evaluate changes in the morphology and expression of progesterone receptor (PR) isoforms in different cell subpopulations of the magnum region of the left oviduct of mature laying and aged nonlaying hens through histomorphometric and immunohistological methods. Histological results demonstrated several changes in the oviduct magnum of mature and aged hens, mainly in the mucosal tissue. Immunohistochemical analysis showed that both PR isoforms are expressed in all cell types of the oviduct magnum of mature laying hens.

Immunohistochemical localization of progesterone receptor isoforms and estrogen receptor alpha in the chicken oviduct magnum during development.

In this work, the immunohistochemical expression of progesterone receptor (PR) isoforms and estrogen receptor alpha (ER-α), as well as the histomorphometric changes of the magnum region of the left oviduct from 8-day-old chicken embryos to one-month-old chickens were evaluated. Results indicate evident histological changes in the oviduct magnum during development mainly in the magnum's mucosa. Immunohistochemical analysis showed that the oviduct magnum from 8-day-old chicken embryos to one-day-old chickens did not present any PR isoform, but the oviduct magnum of one-week and one-month-old chickens expressed PR in the nuclei of all cell types.

Progesterone induces the growth and infiltration of human astrocytoma cells implanted in the cerebral cortex of the rat.

Progesterone (P4) promotes cell proliferation in several types of cancer, including brain tumors such as astrocytomas, the most common and aggressive primary intracerebral neoplasm in humans. In this work, we studied the effects of P4 and its intracellular receptor antagonist, RU486, on growth and infiltration of U373 cells derived from a human astrocytoma grade III, implanted in the motor cortex of adult male rats, using two treatment schemes. In the first one, fifteen days after cells implantation, rats were daily subcutaneously treated with vehicle (propylene glycol, 160  μ L), P4 (1 mg), RU486 (5 mg), or P4 + RU486 (1 mg and 5 mg, resp.

Changes in the cellular localization of estrogen receptor alpha in the growing and regressing ovaries of Gallus domesticus during development.

In this work, the presence of estrogen receptor alpha (ER-α) was determined in different cell subpopulations in the left growing and right regressing ovaries of Gallus domesticus from 13-day-old chicken embryos to one-month-old chickens by immunohistochemistry. Results revealed positive ER-α immunostaining in both ovaries during development, but the percentage, staining intensity, and cellular distribution of ER-α immunostaining changes according to whether it is the left or right ovary and with the animal's age. In the left ovary, the ER-α was localized in the nuclei of the germinal epithelium and in germ cells of the ovarian cortex, as well as in the interstitial cells, undifferentiated cells, and epithelial cells of the lacunar channels of the ovarian medulla in all ages.

Changes in the content of sex steroid hormone receptors in the growing and regressing ovaries of Gallus domesticus during development.

Sex steroids participate in the regulation of reproduction in female chickens. In this work, we determined the content of androgen receptor (AR), intracellular progesterone receptor isoforms (PR-A and PR-B), membrane progesterone receptor γ (mPRγ) and estrogen receptor α (ER-α) in the left growing and right regressing ovaries of Gallus domesticus from 13-day-old chicken embryos to 1-month-old chickens by western blot analysis. A marked difference in the morphological characteristics of the left and the right ovaries during development was observed.

Histological and stereological changes in growing and regressing chicken ovaries during development.

The aim of this study was to evaluate the sequence of the histological and stereological changes that occur in diverse components of left growing and right regressing ovaries of Gallus domesticus as well as the variations in the number and size of the different cell subpopulations from 8-day-old chicken embryo to 4-week-old chickens. Results indicate a bilateral asymmetry in favor of the left ovary at all ages studied. The left ovary shows cortex and medulla, but the right ovary has no cortex, only a medulla.

Histological and stereological studies on Leydig cells in the testes of Gallus domesticus from pre-hatching to sexual maturity.

The present study was aimed at evaluating the sequence of the histological and quantitative changes that occur in diverse components of the interstitial tissue, as well as the variations in the number and volume of Leydig cells of the testes of Gallus domesticus from 8-day-old embryo to 28-week-old chickens. Results indicate an increase in total volume of all components of the interstitial tissue: Leydig cells, blood vessels, and interstitium of chicken testes with advancing development. The proportion of each component differs markedly according to the age of the animal.

Histological and sex steroid hormone receptor changes in testes of immature, mature, and aged chickens.

Sex steroid hormone receptors play a central role in the regulation of reproduction in male chickens. In this work, we evaluated by histomorphometric methods and Western blot analysis changes in the number of the different cell populations and in the content of sex steroid hormone receptors in testes from immature (1.5-month-old), mature (12-month-old), and aged (48-month-old) chickens.

Changes in progesterone receptor isoforms content in the brain of immature, mature and aged male and female chickens.

Progesterone participates in the regulation of several reproductive functions in birds through its interaction with intracellular progesterone receptors (PR) which exhibit two isoforms (PR-A and PR-B) with different function and regulation. We determined the content of PR isoforms in several brain regions of immature (1.5 months-old), mature (12 months-old) and aged (48 months-old) male and female chickens by Western blot analysis.

Immunohistochemical detection of estrogen receptor alpha in the growing and regressing ovaries of newly hatched chicks.

The aim of this study was to detect the presence of estrogen receptor alpha in different cell subpopulations of the growing left and regressing right ovaries from newly hatched chicks, by immunohistochemical methods, using an indirect immunoperoxidase technique. Newly hatched chicks were killed by decapitation and the growing left and regressing right ovaries were removed and processed for histological and immunohistochemical studies. The percentage of estrogen receptor alpha (ERalpha) immunostained cells and the staining intensity were determined.