Biomedical subjects

G Pérez-Palacios

Publications and source records attributed to G Pérez-Palacios.

At least 19 recordsLinked to original sources

PubMed2002

Hormone-like behavioral effects of levonorgestrel and its metabolites in the male rat.

Levonorgestrel (LNG), a contraceptive progestin, exhibits, besides its progestational activity, other hormone-like effects at the peripheral level. To assess whether LNG and its metabolites exert androgenic and/or estrogenic actions at the central nervous system (CNS), their effects on male sexual behavior in castrated rats were examined. LNG, 5alpha-dihydro LNG (5alphaLNG), and the 3alpha,5alpha- and 3beta,5alpha-tetrahydro derivatives of LNG (3alphaLNG and 3betaLNG, respectively) were administered for 3 weeks either alone (1000 microg/day) or in combination (300 microg/day) with 5alpha-dihydrotestosterone (DHT, 300 microg/day) or with estradiol-17beta (E(2), 5 microg/day). Copulatory behavior was assessed twice per week and sex accessory organs weights recorded at the end of treatments. LNG restored full copulatory behavior comparable to that of testosterone treated animals, although with a slight delay, whereas 5alphaLNG induced male sexual behavior in a significantly lower number of subjects. 3betaLNG and 3alphaLNG induced mounting but failed to restore intromission and ejaculation. Combined LNG+E(2) treatment fully activated mounting and intromission, but ejaculation was only partially restored. Combined 5alphaLNG+E(2) treatment and the combinations of 3alphaLNG or 3betaLNG with E(2) were significantly less effective, activating fewer intromissions and ejaculations. 3alphaLNG and 5alphaLNG, in combination with DHT, restored male sexual behavior. LNG, but not its metabolites, induced a significant increase on the weight of sex accessory organs. The overall results demonstrated that high doses of LNG induce a potent androgen agonistic behavioral effect and that its A-ring reduction diminishes this potency and enables a shift towards a weak estrogen-like effect.

Androgens↗

PubMed2001

Assessment of the oestrogenic activity of the contraceptive progestin levonorgestrel and its non-phenolic metabolites.

Levonorgestrel (13beta-ethyl-17alpha-ethynyl-17beta-hydroxy-4-gonen-3-one), a potent contraceptive progestin stimulates growth and proliferation of cultured breast cancer cells through a receptor-mediated mechanism, even though levonorgestrel does not bind to the oestrogen receptor (ER). To assess whether the oestrogen-like effects induced by this synthetic progestin are exerted via its metabolic conversion products, we studied the binding affinity of three A-ring levonorgestrel derivatives to the ER and their capability to transactivate an oestrogen-dependent yeast system co-transfected with the human ER gene and oestrogen responsive elements fused to a beta-galactosidase reporter vector. The results demonstrated that the 3beta,5alpha reduced levonorgestrel derivative and to a lesser extent its 3alpha isomer interact with the oestrogen receptor, with a significantly lower relative binding affinity (2.4% and 0.4%, respectively) than that of oestradiol (100%), while levonorgestrel does not. Both levonorgestrel metabolites were able to activate, in a dose-dependent manner, the beta-galactosidase reporter gene in the yeast expression system, an effect that was precluded by a steroidal antioestrogen. The oestrogenic potency of levonorgestrel metabolites was significantly lower (750-fold) than that of oestradiol. Furthermore, high doses of 3beta,5alpha levonorgestrel (2.5 mg/day/6 days) induced an increase of oestrogen-dependent progestin receptor in the anterior pituitary of castrated rats. The overall data offer a plausible explanation for the weak oestrogenic effects induced by high, non-pharmacological doses of levonorgestrel.

Animals↗

PubMed2001

In vitro metabolism of gestodene in target organs: formation of A-ring reduced derivatives with oestrogenic activity.

Gestodene (13beta-ethyl-17alpha-ethynyl-17beta-hydroxy-4,5-gonadien-3-one), the most potent progestin ever synthesized, stimulates breast cancer cell growth through an oestrogen receptor-mediated mechanism, and its use in hormonal contraception has been associated with side effects attributable to oestrogenic actions. These observations have remained controversial, since gestodene does not bind to the oestrogen receptor or exert oestrogen-like activities. Recently, we have demonstrated that non-phenolic gestodene derivatives interact with oestrogen receptors and induce oestrogenic effects in cell expression systems. To assess whether gestodene is biotransformed to metabolites with intrinsic oestrogenic potency, [3H]- and [14C]-labelled gestodene were incubated in vitro with rat anterior pituitary, hypothalamus and ventral prostate homogenates under different experimental conditions. The most remarkable finding was the isolation and identification of 3beta,5alpha-tetrahydrogestodene and 3alpha,5alpha-tetrahydrogestodene as metabolic conversion products of gestodene, presumably with 5alpha-dihydrogestodene as intermediate. The overall results seem to indicate that the weak oestrogenic effects attributable to gestodene could be mediated by its tetrahydro metabolites.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗

PubMed2001

A-ring reduced metabolites of 19-nor synthetic progestins as subtype selective agonists for ER alpha.

It has previously been demonstrated that 19-nor contraceptive progestins undergo in vivo and in vitro enzyme-mediated A-ring double bond hydrogenation. Bioconversion of 19-nor progestins to their corresponding tetrahydro derivatives results in the loss of progestational activity and acquisition of estrogenic activities and binding to the ER. Herein, we report subtype-selective differences in ligand binding and transcriptional potency of nonphenolic synthetic 19-nor derivatives between ER alpha and ER beta. In this study, we have examined both ER- and PR-mediated transcriptional activity of a number of A-ring chemically reduced derivatives of norethisterone and Gestodene. Double bond hydrogenation decreased the transcriptional potency of norethisterone and Gestodene through both PR isoforms with a 100- to 1,000-fold difference, respectively. In terms of the effects of norethisterone and Gestodene and their corresponding 5 alpha-dihydro (5 alpha-norethisterone and 5 alpha-Gestodene), or 3 alpha,5 alpha-tetrahydro or 3 beta,5 alpha-tetrahydro derivatives (3 alpha,5 alpha-norethisterone/3 alpha,5 alpha-Gestodene and 3 beta,5 alpha-norethisterone/3beta,5 alpha-Gestodene, respectively) on estrogen-mediated transcriptional regulation, the 3 beta,5 alpha-tetrahydro derivatives of both norethisterone and Gestodene showed the highest induction when HeLa cells were transiently transfected with an expression vector for ER alpha. This activity could be inhibited with tamoxifen. These compounds did not activate gene transcription via ER beta, and none of them showed antagonistic activities through either ER subtype. The 3 beta,5 alpha-tetrahydro derivatives of both norethisterone and Gestodene were active in other cells in addition to HeLa cells and activated reporter expression through the oxytocin promoter. In summary, two ER alpha selective agonists have been identified. These compounds, with ER alpha vs. ER beta selective agonist activity, may be useful in evaluating the distinct role of these receptors as well as in providing useful insights into ER action.

Animals↗

PubMed2000

The oestrogenic effects of gestodene, a potent contraceptive progestin, are mediated by its A-ring reduced metabolites.

Gestodene (17 alpha-ethynyl-13 beta-ethyl-17 beta-hydroxy-4, 15-gonadien-3-one) is the most potent synthetic progestin currently available and it is widely used as a fertility regulating agent in a number of contraceptive formulations because of its high effectiveness, safety and acceptability. The observation that contraceptive synthetic progestins exert hormone-like effects other than their progestational activities, prompted us to investigate whether gestodene (GSD) administration may induce oestrogenic effects, even though the GSD molecule does not interact with intracellular oestrogen receptors (ER). To assess whether GSD may exert oestrogenic effects through some of its neutral metabolites, a series of experimental studies were undertaken using GSD and three of its A-ring reduced metabolites. Receptor binding studies by displacement analysis confirmed that indeed GSD does not bind to the ER, whereas its 3 beta,5 alpha-tetrahydro reduced derivative (3 beta GSD) interacts with a relative high affinity with the ER. The 3 alpha,5 alpha GSD isomer (3 alpha GSD) also binds to the ER, though to a lesser extent. The ability of the A-ring reduced GSD derivatives to induce oestrogenic actions was evaluated by the use of two different molecular bioassays: (a) transactivation of a yeast system co-transfected with the human ER alpha (hER alpha) gene and oestrogen responsive elements fused to the beta-galactosidase reporter vector and (b) transactivation of the hER alpha-mediated transcription of the chloramphenicol acetyl transferase (CAT) reporter gene in a HeLa cells expression system. The oestrogenic potency of 3 beta GSD was also assessed by its capability to induce oestrogen-dependent progestin receptors (PR) in the anterior pituitary of castrated female rats. The results demonstrated that 3 beta GSD and 3 alpha GSD were able to activate, in a dose-dependent manner, the hER alpha-mediated transcription of both the beta-galactosidase and the CAT reporter genes in the yeast and HeLa cells expression systems respectively. In both assays the 3 beta derivative of GSD exhibited a significantly greater oestrogenic effect than its 3 alpha isomer, while unchanged GSD and 5 alpha GSD were completely ineffective. Neither 3 beta GSD nor 3 alpha GSD exhibited oestrogen synergistic actions. Interestingly, the pure steroidal anti-oestrogen ICI-182,780 diminished the transactivation induced by 3 beta GSD and 3 alpha GSD in the yeast expression system. Furthermore, administration of 3 beta GSD resulted in a significant increase of oestrogen-dependent PR in the anterior pituitaries of castrated rats in comparison with vehicle-treated animals. The characteristics of the 3 beta GSD-induced PR were identical to those induced by oestradio benzoate. The overall results demonstrate that 3 beta GSD and its 3 alpha isomeric alcohol specifically bind to the ER and possess a weak intrinsic oestrogenic activity, whereas unmodified GSD does not. The data contribute to a better understanding of the GSD mechanism of action and allow the hypothesis to be advanced that the slight oestrogenlike effects attributable to GSD are mediated by its non-phenolic, tetrahydro reduced metabolites.

Animals↗

PubMed1999

Neonatal screening for congenital hypothyroidism in Mexico: experience, obstacles, and strategies.

OBJECTIVE: To report the experience, obstacles, and strategies of screening for congenital hypothyroidism. SETTING: Newborns in Mexico. METHODS: Thyroid stimulating hormone (TSH) was measured by enzyme immunoassay using commercial kits in 1,140,364 newborns. RESULTS: There were 464 positive cases, of whom 299 (64.4%) were girls. 236 (50.9% showed ectopic nodules, 202 (43.5%) thyroid agenesis, 21 (4.5%) dyshormonogenesis, and 5 (1.1%) an unclassified goitre. The false positive rate was 0.024% and there were 11 false negative results. Currently, 600,000 (26%) of the 2,300,000 newborns are screened. This percentage has been increased in recent years by taking samples from cord blood and will be increased further by starting congenital hypothyroidism screening at social security units and by midwives screening infants born at home. CONCLUSIONS: Mental retardation in infants in developing countries can be reduced by neonatal screening, and carefully planned strategies can steadily extend the benefits of screening.

Blood Specimen Collection↗

PubMed1997

A multicenter comparative study on the efficacy, safety, and acceptability of the contraceptive subdermal implants Norplant and Norplant-II.

In order to assess efficacy, safety, and acceptability of the contraceptive subdermal implants Norplant and Norplant-II in Mexican women, a comparative phase III clinical trial was undertaken in eight clinics across the country. The study involved 1052 women who were followed-up trimonthly for three years. Cumulative pregnancy rates were 0.29% and 0.34% for Norplant and Norplant-II implants, respectively. Similar overall cumulative discontinuation rates were observed at three years: 50.38% for Norplant capsules, and 50.44% for Norplant-II rods. The main method-related reason for termination was endometrial bleeding irregularity which led to discontinuation rates of 11.94% and 11.62% for Norplant and Norplant-II contraceptive systems, respectively. In 15,279 woman-months of experience accumulated with Norplant implants and 14,092 with Norplant-II implants, there were few adverse events reported. No difference was found between the two groups in either difficulty for implants placement and removal or women's discomfort, even though the time required for insertion and removal of Norplant capsules was longer than for Norplant-II rods. It is concluded that during the first three years of use, both implants systems are equally effective, safe, and acceptable.

Adult↗

PubMed1997

Transient alteration of the reproductive function in nephrotic rats.

The reproductive function of male and female rats with induced nephrotic syndrome was examined by assessing hormonal levels, the estrous cycle pattern and fertility. Measurements were carried out on day 10 (nephrotic stage) and on day 30 (remission stage) after treatment (a single s.c. dose of puromycin aminonucleoside 15 mg/100 g body wt.). Serum concentrations of luteinizing hormone (LH), follicle-stimulating hormone (FSH) and progesterone (P4) from both sexes as well as 17beta-estradiol (E2) in females and total testosterone (tT) in males were assayed at both phases of the illness by specific radioimmunoassays; free and urine testosterone (fT, uT) was also determined in male rats on day 10. The estrous cycle was followed alongside the study through vaginal smears, while fertility was estimated by the rate of pregnancies (females) or pregnancy induction (males), and by the litter size. The results showed that most serum hormone levels, except FSH in females, were significantly reduced at the nephrotic stage of the illness, returning to their normal values after 30 days. Besides, on day 10, fT was found reduced in nephrotic males, while uT concentrations remained unmodified. The ovulatory cycle of nephrotic rats was disrupted on day 3 and not restored until day 23; nevertheless, the reproductive function, measured as a fertility index, was fully reinstalled at the remission stage. Interestingly, the capacity of fertilization of the nephrotic males was not entirely abolished during the acute phase, since 37% of the animals were fertile. Moreover, on day 30 the reproductive function in nephrotic males was totally recovered. The data from this study show the existence of reversible endocrine disorders in rats bearing nephrotic syndrome; such changes are manifested during the acute phase of the illness as a temporary cessation of the reproductive processes.

Animals↗

PubMed1997

5alpha-reduction of norethisterone enhances its binding affinity for androgen receptors but diminishes its androgenic potency.

Norethisterone (NET), a 19-nor synthetic progestin, undergoes enzyme-mediated 5alpha-reduction and exerts potent androgenic effects in target organs. To investigate its mode of androgenic action we examined, in a comparative manner, the in vitro metabolism of NET and testosterone (T), as well as the binding affinities to androgen receptors (AR) and the androgenic potency of NET, T, and their 5alpha-reduced derivatives. Bioconversion of [3H]-NET and [3H]-T was studied in rat prostate homogenates, AR binding affinity was assessed in rat ventral prostates using [3H]-mibolerone as the radioligand, and the androgenic potency was evaluated by the increase of beta-glucuronidase activity in the mouse kidney, and by the growth of accessory sex organs in castrated male rats. The results demonstrated that 5alpha-NET displayed a higher AR binding affinity but a significantly lower androgenic potency than unchanged NET. The bioconversion studies indicated that the metabolism of NET was similar to that of T, although to a lesser extent, thus ruling out the possibility that the synthetic progestin metabolizes rapidly into less active derivatives. To investigate the nature of the paradoxical effect of 5alpha-reduction upon the NET molecule, the interaction with AR and the androgenic potency of T, 19-nortestosterone (19norT), 17alpha-ethynyl testosterone (ET) and their 5alpha-reduced derivatives were examined. The results of AR binding studies revealed that 5alpha-reduction of T and ET significantly enhanced their affinities, and that the 5alpha-derivative of 19norT displayed a similar binding affinity to that exhibited by 19norT. In terms of biological activity, the results showed that 5alpha-reduction of T and 19norT significantly increased their androgenic potency, whereas 5alpha-reduction of ET resulted in a significant diminution of its androgenicity in a manner similar to that observed with the 5alpha-reduction of NET. When NET and 19norT were simultaneously administered with 5alpha-dihydrotestosterone they exhibited a potent synandrogenic activity, an effect that was cancelled by their 5alpha-reduction. Interestingly, ET displayed an antiandrogenic activity, an effect that was also suppressed by its 5alpha-reduction. The overall results demonstrated a distinctive, paradoxical effect of 5alpha-reduction upon the NET molecule, which was different from that seen in naturally occurring androgens, and which suggests that the presence of the 17alpha-ethynyl group plays a key role in this phenomenon. The data provided further evidence that the metabolism of synthetic contraceptive progestins modulates the expression of their hormone-like actions.

Androgens↗

PubMed1997

Mutations of the 5 alpha-reductase type 2 gene in eight Mexican patients from six different pedigrees with 5 alpha-reductase-2 deficiency.

BACKGROUND AND OBJECTIVE: Male pseudohermaphroditism due to 5 alpha-reductase deficiency was originally described in 1974. Recently, 5 alpha-reductase Type 2 gene defects have been found generally to be due to point mutations within the 5 exons of the 5 alpha-reductase-2 gene. In this report, we describe the molecular study of patients with 5 alpha-reductase deficiency. DESIGN: Previously diagnosed patients with 5 alpha-reductase deficiency were sampled in order to perform molecular studies. PATIENTS: Eight 5 alpha-reductase deficient individuals from 6 unrelated families. MEASUREMENTS: Single-strand conformational polymorphism and DNA sequencing were performed after polymerase chain reaction amplification of each of the 5 exons of the gene. RESULTS: Five different missense mutations were found. In 4 patients a cytosine to guanine substitution was observed at codon 212 in exon 4. Two siblings presented a cytosine to adenine substitution at codon 207 in exon 4. Another patient exhibited a guanine to adenine substitution at codon 34 in exon 1, whilst one individual presented 2 mutations: a guanine to adenine substitution at codon 115 in exon 2 and a guanine to adenine substitution at codon 203 in exon 4 (previously undescribed mutation). CONCLUSIONS: The presence of the same mutation in 4 patients from 3 families indicates the increased prevalence of this mutation in a particular ethnic group, suggesting a common ancestry for the gene defect in these patients. The existence of hot spots is supported by the mutations in codons 34 and 207 which have also been found in other ethnic groups. Interestingly, the patient who presented 2 different mutations, one of them previously undescribed, was reared as a male and exhibited a more masculine phenotype. Further studies in patients with this and other mutations will be needed to verify genotype-phenotype correlation.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗

PubMed1996

Molecular analysis in true hermaphrodites with different karyotypes and similar phenotypes.

True hermaphroditism is characterized by the development of ovarian and testicular tissue in the same individual. Müllerian and Wolffian structures are usually present, and external genitalia are often ambiguous. The most frequent karyotype in these patients is 46,XX or various forms of mosaicism, whereas 46,XX is very rarely found. The phenotype in all these subjects is similar. We studied 10 true hermaphrodites. Six of them had a 46,XX chromosomal complement: 3 had been reared as males and 3 as females. The other 4 patients were mosaics: 3 were 46,XX/46,XY and one had a 46,XX/47,XXY karyotype. One of the 46,XX/46,XY mosaics was reared as a female, whereas the other 3 mosaics were reared as males. The sex of assignment in the 10 patients depended only on labio-scrotal differentiation. Molecular studies in 46,XX subjects documented the absence of Y centromeric sequences in all cases, arguing against hidden mosaicism. One patient presented Yp sequences (ZFY+, SRY+), which contrast with South African black 46,XX true hermaphrodites in whom no Y sequences were found. Molecular analysis in the subjects with mosaicism demonstrated the presence of Y centromeric and Yp sequences confirming the presence of a Y chromosome. Gonadal development, endocrine function, and phenotype in the 10 patients did not correlate with the presence of a Y chromosome or Y-derived sequences in the genome, confirming that true hermaphroditism is a heterogeneous condition.

Adolescent↗

PubMed1995

SRY alone can induce normal male sexual differentiation.

Most individuals with the rare 46,XX male "syndrome" arise due to an unequal interchange between Xp and Yp termini during paternal meiosis. The pattern of Y-sequences in these patients varies considerably, but very few cases have been reported showing only SRY. The phenotype in these patients is also variable ranging from severe impairment of the external genitalia through hypospadias and/or cryptorchidism to occasional normal male phenotype. We report a Mexican 46,XX male patient without genital ambiguities in whom DNA analysis showed the presence of SRY and the absence of ZFY. We conclude that in this case SRY alone was enough for complete male sexual differentiation.

DNA-Binding Proteins↗

PubMed1995

Molecular mechanisms of the antihormonal and antiimplantation effects of norethisterone and its A-ring reduced metabolites.

Norethisterone (NET) has been used as a contragestational postcoital agent. It is biotransformed to 5 alpha dihydro-NET (5 alpha-NET) and 3 beta,5 alpha tetrahydro-NET (3 beta,5 alpha-NET) in target tissues. The participation of these metabolites in NET effects is unknown. We have examined the antiimplantation and antiprogestational effects of NET and its metabolites, in adult mated female rabbits, by assessing the number of implantation sites and the expression products of the uteroglobin (UTG) gene in the uterus, and by comparing them with those of RU-486 and estradiol. Steroids were daily administered s.c. at several doses for 7 consecutive days, starting 24 hr after coitus. To assure that fertilization occurred in all animals, the presence of early pregnancy factor was determined. The results demonstrated that high doses (5 mg/kg) of NET reduced both implantation and the expression of the UTG gene. On the other hand, lower doses (1.5 mg/kg) of 5 alpha-NET produced an antiimplantation effect and suppressed UTG synthesis and its mRNA. These effects were similar to those of RU-486. At lower doses (1 mg/kg), both estradiol and the estrogenic metabolite 3 beta,5 alpha-NET were also effective in inhibiting implantation and UTG gene expression. The overall results suggest that NET metabolites exert antiimplantation and antiprogestational effects through their interaction with progesterone and estrogen receptors, and provide an explanation for the molecular mechanisms involved in the postcoital contraceptive action of NET.

Animals↗

PubMed1995

Male pseudohermaphroditism due to primary 5 alpha-reductase deficiency: variation in gender identity reversal in seven Mexican patients from five different pedigrees.

In the present study, we describe the clinical, endocrinological, psychosexual and biochemical features of 7 Mexican male pseudohermaphrodites with primary 5 alpha-reductase deficiency in whom heterogeneity in the pattern of gender identity change at puberty was observed. The patients belonged to 5 different pedigrees from diverse locations in Mexico. Six of them were admitted to the Hospital during or after puberty. The one prepubertal subject was the sibling of a previously studied patient. Basal serum gonadotropins were determined by double antibody radioimmunoassay. Basal and choriogonadotropin (CG)-stimulated concentrations of androstenedione (A), testosterone (T) and dihydrotestosterone (DHT) were determined by radioimmunoassay after extraction and separation by celite chromatography. Urinary aetiocholanolone, androsterone and C19 and C21 5 beta/5 alpha metabolite ratios were analyzed by capillary gas chromatography. Enzyme activity and androgen receptors were studied in fibroblasts cultured from genital skin. Psychological assessment was performed using the Bender-Gestalt Wechsler Adult Intelligence Scale, the Rorschach Ink Blot and the Thematic Apperception Tests. All 7 patients were unambiguously reared as females; three spontaneously changed their gender identity and role from female to male after puberty, another one changed during psychotherapy at the end of puberty. Two patients (one prepubertal and the other pubertal) have been under therapy during 1.5 years, but due to familial and social factors a female gender has prevailed. The remaining patient consulted at age 15 because of virilization; her female gender identity did not change after more than one year of treatment and due to the fact she was depressed and had suicidal tendencies, the penis and testes were removed.(ABSTRACT TRUNCATED AT 250 WORDS)

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗

PubMed1995

Molecular interactions of levonorgestrel and its 5 alpha-reduced derivative with androgen receptors in hamster flanking organs.

The 5 alpha-reduction of levonorgestrel (LNG) as well as its binding capacity to the androgen receptors of the hamster flank organ were investigated. Furthermore, the effects of LNG and its 5 alpha-reduced metabolite in the flank organ test and on [U-14C]glucose incorporation into lipids by this tissue were determined. Homogenates from female hamster flank organs were incubated in the presence of [3H]LNG at pH 7.4. The radioactive 5 alpha-LNG metabolite was isolated and its purity was assessed. Competition experiments for androgen binding receptors were carried out with 1.38 nM [3H-7 alpha-17 alpha]dimethyl-19- nortestosterone (DMNT), Kd, plus a range of increasing concentrations of the different unlabeled steroid hormones. The flank organ test was performed in vivo, and [U-14C]glucose incorporation into lipids was determined under organ culture conditions. The 5 alpha-LNG had the same binding capacity to androgen receptors (AR) as LNG in male flank organs. The flank organ test demonstrated that 5 alpha-LNG activity was similar to that observed for levonorgestrel and testosterone (T) on gonadectomized male hamster flank organs. Topical applications of LNG or 5 alpha-LNG increased [U-14C]glucose incorporation into lipids in a way similar to that of T. The overall data indicate that LNG and 5 alpha-LNG produced androgenic activity in the lipid pathway of male flank organs, and that 5 alpha-reduction is not essential for the LNG effect on this tissue.

Animals↗

PubMed1995

Clinical traits and molecular findings in 46,XX males.

46,XX maleness is characterized by the presence of testicular development in subjects who lack a Y chromosome. The majority of affected persons have normal external genitalia, but 10-15% show various degrees of hypospadias. Several hypotheses have been proposed to explain the etiology of this constitution: translocation of the testis-determining factor (TDF) from the Y to the X chromosome, mutation in an autosomal or X chromosomal gene which permits testicular determination in the absence of TDF, and undetected mosaicism with a Y-bearing cell line. We report the phenotypic data and results of molecular analyses performed in six sporadic Mexican males with 46,XX karyotype. Molecular studies revealed Yp sequences in two individuals (ZFY+ SRY+) with different phenotypes, a third one presented with a smaller segment of Yp (ZFY- SRY+) and complete virilization, while the remaining three were Y-negative and showed hypospadias. In all subjects a hidden mosaicism with a Y-bearing cell line was ruled out due to the absence of Y-centromeric sequences. Our data demonstrate that the phenotype does not always correlate with the presence or absence of Y-sequences in the genome, and confirm that 46,XX maleness is a genetically heterogeneous condition.

Adolescent↗

PubMed1995

Pituitary-ovarian dysfunction in rats with induced nephrotic syndrome.

The reproductive hormonal profile was evaluated in female rats with experimental nephrotic syndrome induced with a single subcutaneous dose of puromycin aminonucleoside (PAN). Serum concentrations of luteinizing hormone (LH), follicle-stimulating hormone (FSH), progesterone (P4), testosterone and 17 beta-estradiol (E2) were determined sequentially in control and experimental groups on days 1, 3, 7 and 10 after PAN administration. Prolactin levels were also assessed on day 10. In both groups, vaginal smears were taken daily throughout the study to evaluate cyclic histological changes. At the end of the experiment the histological appearance of the ovaries was evaluated by light microscopy. Nephrotic rats had a rapid loss of the estrous cycle starting on day 4, which set them at diestrus. At the same time the hormonal evaluation indicated a gradual decrease in E2, LH and P4 concentrations, starting from days 3, 7 and 10, respectively. No significant changes were noted in FSH or testosterone values. Besides, on day 10, prolactin concentrations remained unmodified. Even though most hormonal levels were found low on day 10, all values except E2 (undetectable) corresponded to the interval reported for the diestrus phase. Likewise, histological examination of ovarian tissue from nephrotic rats showed a considerable increase in the number of atretic follicles. These findings indicate that female rats with nephrotic syndrome develop an important endocrine dysfunction that probably involves steroidogenic tissues (ovary and/or adrenal gland), and suggest the existence of a hypothalamic-hypophyseal impairment.

Animals↗

PubMed1995

In vitro molecular assessment of the mechanisms of action of 19-nor progestins used as contragestational agents.

Norethisterone (NET) and levonorgestrel (LNG) are synthetic progestins used as contragestational agents. Both compounds are biotransformed at target tissues into A-ring reduced metabolites which possess different pharmacological properties. The aim of this study was to determine the molecular mechanisms of the progestational and antiprogestational effects of NET, LNG and their metabolites by using a highly efficient, sensitive in vitro molecular assay based on the detection of a reporter gene expression (the bacterial chloramphenicol acetyltransferase (CAT) inserted downstream of a minimal promoter containing two progesterone responsive elements (PRE2) and the TATA box. For this purpose we used CV-1 monkey kidney cells, which do not possess steroid receptors. These cells were cotransfected with a progesterone receptor expression vector and the reporter vector PRE2-TATA-CAT. Data obtained using this model showed that NET and LNG induced CAT activity in a manner similar to that of the potent progestin R5020. NET and LNG metabolites exhibited a weak progestational activity; however, when 5 alpha-NET metabolite was simultaneously administered with R5020, a clear antiprogestational effect similar to that of the antiprogestin RU486 was observed. Therefore, the results clearly demonstrate that the use of the reporter CAT vector containing hormone responsive elements is a suitable assay for the screening and evaluation of new synthetic steroids with agonist or antagonist progestational activities in transfected CV-1 cell line.

Animals↗