Biomedical subjects

C Guerra-Araiza

Publications and source records attributed to C Guerra-Araiza.

7 recordsLinked to original sources

PubMed2003

Changes in progesterone receptor isoforms content in the rat brain during the oestrous cycle and after oestradiol and progesterone treatments.

We studied the effects of oestradiol and progesterone on progesterone receptor (PR) isoform content in the brain of ovariectomized rats and in intact rats during the oestrous cycle by Western blot analysis. In the hypothalamus and the preoptic area of ovariectomized rats, PR-A and PR-B content was increased by oestradiol, whereas progesterone significantly diminished the content of both PR isoforms after 3 h of treatment in the hypothalamus, but not in the preoptic area. In the hippocampus, only PR-A content was significantly increased by oestradiol while progesterone significantly diminished it after 12 h of treatment. In the frontal cortex, no treatment significantly modified PR isoform content. During the oestrous cycle, the lowest content of PR isoforms in the hypothalamus was observed on diestrus day and, by contrast, in the preoptic area, the highest content of both PR isoforms was observed on diestrus day. We observed no changes in PR isoform content in the hippocampus during the oestrous cycle. These results indicate that the expression of PR isoforms is differentially regulated by sex steroid hormones in a regionally specific manner.

Animals↗

PubMed2001

Progesterone receptor isoforms expression in the prepuberal and adult male rat brain.

Progesterone receptor (PR) isoforms expression was determined in several regions of the prepuberal and adult male rat brain by using reverse transcription coupled to polymerase chain reaction. Rats under a 14:10-h light-dark cycle, with lights on at 0600 h were used. We found that in the hypothalamus of prepuberal animals the expression of both PR isoforms was similar, whereas PR-A expression was higher than that of PR-B in adults. In the cerebellum PR-B expression was predominant in both prepuberal and adult rats. In both ages PR-A and PR-B exhibited a non-significant tendency to be predominant in the hippocampus and the preoptic area respectively. In the frontal cortex and the olfactory bulb PR isoforms were expressed at a similar level. These results indicate a differential expression pattern of PR isoforms in the male rat brain and suggest that the tissue-specific expression of PR-A and PR-B is important for the appropriate response of each cerebral region to progesterone.

Age Factors↗

PubMed2000

Progesterone receptor isoforms expression pattern in the rat brain during the estrous cycle.

Progesterone receptor (PR) isoforms expression was determined in the hypothalamus, the preoptic area, the hippocampus and the frontal cerebral cortex of the rat at 12:00 h on each day of the estrous cycle by using reverse transcription coupled to polymerase chain reaction. Rats under a 14:10 h light-dark cycle, with lights on at 06:00 h were used. We found that PR-B isoform was predominant in the hypothalamus, the preoptic area and the frontal cerebral cortex. Both PR isoforms were similarly expressed in the hippocampus. The highest PR-B expression was found on proestrus day in the hypothalamus; on metestrus in the preoptic area; and on diestrus in the frontal cortex. We observed no changes in PR isoforms expression in the hippocampus during the estrous cycle. These results indicate that PR isoforms expression is differentially regulated during the estrous cycle in distinct brain regions and that PR-B may be involved in progesterone actions upon the hypothalamus, the preoptic area and the frontal cortex of the rat.

Animals↗

PubMed1998

Progesterone receptor isoforms are differentially regulated by sex steroids in the rat forebrain.

We studied the effects of estradiol (E2) and progesterone (P4) on expression of genes coding for PR isoforms in the forebrain of ovariectomized rats by RT-PCR analysis. In the hypothalamus the expression of both PR isoforms was induced by E2 and down-regulated by P4. In the preoptic area these changes were only observed in the PR-B isoform. In contrast, in the hippocampus PR induction by E2 was only observed for PR-A. In this region P4 did not modify the expression of any PR isoform. These results indicate that PR isoforms expression is differentially regulated by sex steroid hormones in distinct forebrain regions and suggest that the tissue-specific regulation of either PR-A or PR-B may be involved in the physiological actions of P4 upon the rat brain.

Animals↗

PubMed1998

C-fos expression pattern in the hypothalamus and the preoptic area of the rat during proestrus.

c-fos gene expression in the hypothalamus, the preoptic area, the hippocampus and the frontal cerebral cortex of the rat was determined every two hours from 09:00 h to 19:00 h on the day of proestrus by using reverse transcription coupled to polymerase chain reaction. Rats under a 14:10 h light-dark cycle, with lights on at 06:00 h were used. We found a marked increase in c-fos gene expression in the studied regions but the hippocampus at 13:00 h, followed by a significant diminution in the subsequent hours of proestrus day. The high expression of c-fos gene at 13:00 could be associated to the increase in estradiol seric levels observed both at 11:00 h and at 13:00 h. Our results correlate with the increase in the number of FOS immunoreactive cells in some forebrain areas in proestrus afternoon related to gonadotropin releasing hormone secretion.

Animals↗

PubMed1998

Changes in progesterone receptor mRNA content in the rabbit lung during early pregnancy and after sex steroid hormone treatment.

In this work we determined progesterone receptor (PR) mRNA content in female rabbit lung during the first 5 days of pregnancy and in ovariectomized animals after subcutaneous injection of oestradiol benzoate (25 micrograms/kg) for 2 days or oestradiol benzoate (25 micrograms/kg) for 2 days plus a single dose of progesterone (5 mg/kg) on day three. On each day (0-5) of pregnancy and 24 h after the last dose in the case of the treated animals, animals were killed and lung was excised; total RNA was extracted and processed for Northern blot analysis. The results showed three main PR mRNA transcripts (6.1, 4.4 and 1.8 kb) in rabbit lung. The 4.4 kb species was the most abundant. PR mRNA content was markedly increased by oestradiol benzoate and downregulated by progesterone. It significantly increased on the first day of pregnancy and then diminished progressively, reaching its lowest value on day 5. These findings suggest that PR mRNA content in the rabbit lung is regulated by sex steroid hormones and changes according to the physiological concentrations of oestradiol and progesterone.

Animals↗

PubMedDate not supplied

[Progesterone receptor isoforms: function and regulation].

Progesterone participates in the regulation of several physiological processes in mammals. The biological response to progesterone is mediated by two forms of the progesterone receptor (PR) denominated PR-A and PR-B. The difference between them is that 164 amino acids of N-terminal of PR-B are absent in PR-A. Both PR isoforms are derived from a single gene but are generated from either alternative transcriptional or translational start sites, and are regulated by different estrogen-induced promoters. PR-B acts as a transcriptional activator in different cellular contexts whereas PR-A functions as a strong inhibitor of transcriptional activity. PR isoforms expression and function vary among target tissues such as the uterus, the mammary gland and the brain. The knowledge of the molecular mechanisms involved in the regulation of expression and function of PR isoforms will contribute to the understanding of fundamental biological processes such as sexual behavior and reproduction, and it will open the possibility of alternative therapies in fertility control as well as in the treatment of breast, endometrial and cerebral tumors.

Central Nervous System↗