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PubMed1985

The influence of male and female best friends on adolescent sexual behavior.

Using panel data from a junior high school system in an urban area of Florida, we examine whether adolescents' best same-sex and best opposite-sex friends' sexual intercourse behavior increases the likelihood that respondents who are virgins at round 1 will make the transition to intercourse between rounds of our study. We find no significant influence effects of friends of either sex for black males or females, or white males. In contrast, white females are influenced by the sexual behavior of both their best female friend and best male friend. A virgin white female whose best friends of both sexes were sexually experience at round 1 was almost certain to have sexual intercourse within the two years of our study.

Adolescent↗
PubMedDate not supplied

Adolescent pregnancy.

Explore the source record for details and available documents.

Abortion, Legal↗
PubMed1982

[Effect of p-chlorophenylalanine on LH, FSH, prolactin and ovulation in the rat].

The effect of p-chlorophenylalanine (PCPA: 300 mg/kg) on the rate of ovulation and plasma LH, FSH and prolactin secretion has been studied in rats at preovulatory periods (18th hour of diestrus) and post-ovulatory periods (9th hour of metaestrus). In both experimental groups, results showed that administration of PCPA caused an increase in both prolactin concentration and number of mature ovarian follicles (p less than 0.001). No changes were observed in FSH levels. LH concentration, however, decreased (p less than 0.001) and ovulation became totally inhibited. Rats treated at the 9th hour of metaestrus exhibited a marked luteinization as well as an increased number of corpus luteum in the ovaric tissue (p less than 0.001), whereas those treated at the 18th hour of diestrus underwent no luteinization and merely showed a greater number of mature ovarian follicles (p less than 0.001). PCPA, therefore, seems not to have a double effect on ovulation, LH, FSH, and prolactin secretion regardless of the pre or post-ovulatory periods. Changes observed in the ovaric tissue might be due to an increase in plasma prolactin concentration which appears earlier in the preovulatory than in the post-ovulatory treated animals. This difference may explain the double effect that has been attributed to the ovaric cycle and reproductive behavior.

Animals↗
PubMed1983

Contraception with levonorgestrel, 0.15 mg, and ethinyl estradiol, 0.03 mg. Clinical studies in Latin America.

Levonorgestrel, 0.15 mg, and ethinyl estradiol, 0.03 mg, an ultra-low-dose oral contraceptive product, was studied in Latin America. In total, 1,206 sexually active, fertile women in their reproductive years were followed through 9,736 cycles. Only one of eight pregnancies was attributed to failure of the medication, resulting in a corrected Pearl index of 0.13. Very good cycle regulation was achieved, with an acceptably low rate of intermenstrual bleeding. The medication was discontinued for medical reasons in only 5% of the patients. Apart from a mild case of thrombophlebitis, there were no major side effects. These studies show that this combination oral contraceptive provides effective contraception with a very low incidence of side effects.

Clinical Trials as Topic↗
PubMed1984

Menstrual history and fecundity of women exposed and unexposed in utero to diethylstilbestrol.

Sequential examination and interview of diethylstilbestrol-exposed (DES-exposed) and -unexposed women verified that DES exposure has no effect on age at menarche and indicated no differences in the age at first coitus, pregnancy and live birth. Analysis of variance indicated that there is an age-related increase in oligomenorrhea in DES-exposed women as compared to unexposed women that disappears as the patients reach their late 20s. Prospective data collection is required to substantiate this finding. There appears to be no substantial effect of in utero exposure to DES on women's ability to conceive.

Abortion, Induced↗
PubMed1983

Cholecystitis in teenage girls.

Cholecystectomy was carried out in 17 teenage girls for cholecystitis at Virginia Mason Hospital, Seattle, between 1971 and 1980. The incidence increased with increasing age. Gallbladder disease was associated with recent pregnancy or birth control pill use (71%), obesity (65%) and family history of gallbladder disease (47%). All but one patient had at least one of these risk factors. No patient had congenital anomalies, blood dyscrasias or other underlying illness. Patients most commonly had recurrent attacks of abdominal pain; seven had symptoms for more than six months. Although the clinical presentations were often mild, six patients had jaundice, three had chemical pancreatitis, one had hemorrhagic pancreatitis, one had pancreatic pseudocyst and abscess and one had a common duct stone. One patient had cholesterosis and 16 had cholelithiasis. All patients were cured by operation. During the same time period, only two boys, both aged 14 years, nonobese and with no family history of gallbladder disease, underwent cholecystectomy, both for acaculous cholecystitis.

Adolescent↗
PubMed1978

Effects of prostaglandin synthesis inhibitor, indomethacin on estrogen- and estrogen plus progesterone-induced sexual receptivity in ovariectomized rats.

Implants of crystalline PGE2 in the basal preoptic-anterior hypothalamic areas stimulates high levels of sexual receptivity in ovariectomized, estrogen-primed rats. Indomethacin, which blocks the synthesis of PGE2 failed to inhibit either estrogen- or estrogen plus progesterone-induced receptivity. Neither intracerebral nor subcutaneous administration of indomethacin diminished the display of steroid induced reproductive behavior without also causing a depression in open-field activity, and in some cases, causing gastrointestinal problems and even death. These results suggest the prostaglandin synthesis is not a required step in the mechanism by which estrogen and progesterone exert their behavioral effects. The possibility that PGE2 and LH-RH synthesis and/or release might contribute to a collateral mechanism for the induction of sexual receptivity was discussed.

Animals↗
PubMed1982

Estradiol receptor levels in rat hypothalamic and limbic nuclei.

The amount of cytoplasmic receptor for the steroid hormone, estradiol (E2), was determined in 46 nuclei and subdivisions of rat brain. Individual nuclei were removed from 300-micrometers frozen sections according to the punch-out method of Palkovits (Palkovits, M. (1973) Brain Res. 59: 449-450), and the content of E2 receptor was measured with a sensitive radioligand binding method. Cytoplasmic receptors for E2 were distributed heterogeneously throughout the rat brain. The highest level of receptor (40 fmol/mg of protein) was found in the periventricular nucleus of the preoptic area, while low (1 fmol/mg) but detectable levels of receptors were found in such limbic regions as the nucleus of the diagonal band, the olfactory tubercle, and the cingulate cortex. Regions that were devoid of detectable receptor included the medial septum, the parietal cortex, and the ventral thalamus. Our results support the notion that E2 influences reproductive behavior and neuroendocrine function by binding to receptors in discrete areas of the brain and provide the first quantitative map of E2 receptors in individual rat brain nuclei.

Animals↗
PubMed1995

Progesterone enhances an estradiol-induced increase in Fos immunoreactivity in localized regions of female rat forebrain.

In female rats, the onset of reproductive behavior depends on the sequential presence of estradiol followed by progesterone. Although treatment with high doses of estradiol has been shown to increase immunostaining for the Fos protein, an immediate early gene product that is expressed upon cellular activation, another report conflicts with this finding. However, the previous reports agree that subsequent treatment with progesterone has no apparent effect on Fos expression. In order to resolve this discrepancy and investigate possible effects of progesterone, we used Fos immunocytochemistry combined with computer-aided image analysis. In experiment one, we found that treatment with 5 micrograms of estradiol increased Fos immunoreactivity (Fos-IR) within a section of the medial preoptic area and the dorsal medial hypothalamus. Subsequent treatment with 500 micrograms of progesterone 1 hr before perfusion increased the intensity of the immunostaining within the medial preoptic area and the dorsal medial hypothalamus, although it had no significant effect on Fos-IR cell number. In experiment 2, a lower concentration of Fos antiserum was used in order to diminish the immunostaining sensitivity to a level in which no increase of Fos-IR cell number was observed after treatment with estradiol. Under these immunocytochemical conditions, subsequent treatment with progesterone increased the number of Fos-IR cells in the medial preoptic area, the dorsal medial hypothalamus and the steroid receptor-rich area lateral to the ventromedial hypothalamus. Thus, treatment with behaviorally effective doses of both estradiol and progesterone induces Fos expression in localized regions of female rat brain.

Animals↗
PubMed1994

Neuronal and non-neuronal aromatase in primary cultures of developing zebra finch telencephalon.

Estrogenic metabolites of circulating androgens have important effects on the organization and activation of neural circuits controlling reproductive behavior and physiology in males of many vertebrate species. Previous studies indicate that aromatase, the enzyme that converts androgens to estrogens, is expressed most abundantly in neurons in limbic brain regions. Songbirds are unique in that aromatase is expressed at unusually high levels throughout the telencephalon of both males and females. We assume that estrogens formed in the telencephalon itself masculinize neural circuits controlling song, since the brain is a major source of circulating estrogens in adult males. However, the cellular localization of telencephalic aromatase in songbirds remains unknown. We have established primary cultures from telencephalons of developing zebra finches and found aromatase activity (conversion of 3H-androstenedione or 3H-testosterone to 3H-estrone plus 3H-estradiol) at some of the highest levels reported for brain tissue of any species. Both neurons and glia were identified in these cultures based on cell morphology and labeling by specific immunohistochemical markers. However, when culture conditions were manipulated to reduce the incidence of either neurons or glia by varying the age of cultures or their plating density, treating with the neurotoxin kainic acid, physically shaking off loosely attached neurons, or preparing cultures in media that encouraged enrichment of neurons, high levels of aromatase persisted. Furthermore, Northern blot analysis of total RNA extracted from enriched neuronal or glial cultures indicated the presence of aromatase mRNA in both cell preparations. In situ hybridization with a zebra finch aromatase cDNA probe conjugated to digoxigenin showed the cultures contained darkly labeled neurons and lightly labeled non-neuronal cells, presumably astrocytes. We conclude that aromatase is expressed in both neuronal and non-neuronal cells in these cultures, suggesting that both cell types may also express the enzyme in vivo. The presence of aromatase outside of neurons suggests that glia may be targets of estrogen action or that glia may supply some estrogen to the estrogen-sensitive neural circuits in this species.

Aging↗