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Biomedical subjects

S C Chattoraj

Publications and source records attributed to S C Chattoraj.

At least 19 recordsLinked to original sources
PubMed2001

Urinary excretion pattern of catecholestrogens in preovulatory LH surge during the 4-day estrous cycle of rats.

The formation of catecholestrogens represents a major pathway of estrogen metabolism and catecholestrogens are regarded as the main estrogen metabolite in non-pregnant state of various mammalian systems. In the present investigation, level of 2-hydroxyestrone, the major catecholestrogen excreted in rat urine, was measured by radioimmunoassay following acid hydrolysis and column chromatography of the 24-h urine samples of female Sprague Dawley non-pregnant rats during their 4-day estrous cycle. Urinary levels of estrone, estradiol and estriol were measured. Unlike the plasma level, urinary 2-hydroxyestrone showed a marked increase during the pre-ovulatory LH surge suggesting a plausible role of catecholestrogen in the mid-cycle elevation of the gonadotropin level in normal cycling rats.

Animals↗
PubMed1999

Correlation of neomycin, faecal neutral and acid sterols with colon carcinogenesis in rats.

High fat diets have been implicated in incidence of colon cancer both in epidemiological and animal studies. Present investigation deals with the incidence, location and numbers of large and small bowel tumours induced by 1,2-dimethyl hydrazine (DMH) in rats fed high fat diets and neomycin. Neomycin was used to modify the faecal sterol metabolism and the relationship of the high fat diet and faecal neutral and acid sterols to the large bowel tumorigenesis was evaluated. DMH administered rats were fed with (a) 20% safflower oil; (b) 20% safflower oil and neomycin; (c) 20% safflower oil, cholesterol and cholic acid; and (d) 20% safflower oil, cholesterol, cholic acid and neomycin. Neomycin was found to be associated with both increase and decrease of tumour numbers. The faecal sterols lithocholic and deoxycholic acids were found to have no participation, while cholesterol and cholic acid were found to decrease with increase in tumour numbers. However, faecal coprostanol has been found to have a significant positive correlation with tumorigenesis in all dietary groups. Therefore coprostanol might possibly be associated with colon carcinogenesis in DMH-fed rats and cholesterol metabolism in gut appears to be related to the development of tumours.

1,2-Dimethylhydrazine↗
PubMed1991

Do catechol estrogens participate in the initiation of labor?

To assess the role of catechol estrogens in the initiation of labor, we compared the levels in amniotic fluid during the second and third trimesters and from women undergoing cesarean section at term not in labor and those with spontaneous labor at term. Catechol estrogen concentrations in amniotic fluid increased significantly with the progress of pregnancy. Further, concentrations (mean +/- SE) were significantly higher in spontaneous labor at term (468.6 +/- 29.5 pg/ml) compared with those obtained during cesarean section (242.6 +/- 22.3 pg/ml) at term not in labor. We suggest that catechol estrogens, through their stimulating effects on prostaglandin synthesis, participate in the initiation of labor.

Adult↗
PubMed1991

Identification of 19-norprogesterone in pregnant rat urine.

The existence of biosynthetic pathways leading to the formation of 19-nor-androgens and corticoids have been established in animals and humans. The exact biologic function of the products of these pathways in vivo has yet to be established; however, it has been shown that they possess pronounced biologic activity when administered exogenously. This report describes the identification of 19-nor-progesterone isolated from the urine of pregnant rats. The procedures used included isolation as the underivatized material and methoxime derivative by thin-layer and high-performance chromatography. The identity was further confirmed by gas chromatography/mass spectral analysis of the isolated product as the 3,20-bis-methoxime derivative. The spectra obtained from the urinary product and the authentic 19-norprogesterone-3,20-bis-methoxime were identical. A possible biologic role for 19-norprogesterone or its precursors is discussed.

Animals↗
PubMed1991

Temporal relationships among the excretory patterns of 2-hydroxyestrone, estrone, estradiol, and progesterone during pregnancy in the rat.

The urinary excretion pattern of 2-hydroxyestrone, estradiol, estrone, and progesterone was examined in rats during early, mid, and late pregnancy. Progesterone increased from early to mid pregnancy and declined significantly 2 to 3 days prior to parturition, corresponding to changes observed in blood levels by others. 2-Hydroxyestrone, the major estrogen in rat urine, increased significantly 4 days prior to delivery and remained elevated until it further increased sharply the day of parturition. Urinary estradiol and estrone levels showed little change until the day of parturition, when they increased significantly. Multiple correlation analysis of the data implied that 2-hydroxyestrone and estradiol were negatively correlated at the time of implantation. The results suggest that catechol estrogens, through their effect on prostaglandin synthesis, may participate in the process of implantation as well as in the mechanism involved in the onset of labor.

Animals↗
PubMed1988

Catechol estrogen concentrations in maternal and umbilical circulation at different modes of delivery.

To investigate the role of catechol estrogens in human parturition, these steroids were analyzed in samples from the maternal venous and umbilical venous and arterial plasma at vaginal (n = 28) and abdominal (n = 28) delivery. To ensure the appropriateness of collection of umbilical artery and venous blood samples, progesterone content was also determined. Although there is no significant difference in maternal vein content of catechol estrogens between the two groups, the umbilical venous (p = 0.03) and arterial (p = 0.002) plasma concentrations are significantly higher at vaginal delivery than those measured at abdominal delivery. In view of the present data and the importance of catechol estrogens in prostaglandin synthesis and in potentiating the activity of catecholamines through competitive inhibition of catechol-O-methyltransferase, it is suggested that catechol estrogens may play a role in triggering the events involved in the onset of labor and delivery in humans.

Cesarean Section↗
PubMed1983

The absence of a catechol estrogen effect on blood pressure in the male rat.

Since catechol estrogens are potent competitive inhibitors of catechol-O-methyl transferase (COMT), it has been suggested that they may prolong the half-life of catecholamines which in turn can cause hypertension. Thus, experiments were carried out to study the effect of catechol estrogens on blood pressure in the male rat following chronic administration. Results demonstrate that 2-hydroxyesterone (2,3-dihydroxyestra-1,3,5(10)-trien-17-one) and 2-hydroxy-estradiol (estra-1,3,5(10)-triene-2,3,17 beta-triol) even when administered in high doses do not alter blood pressure.

Animals↗
PubMed1983

Urinary catechol estrogens in cycles stimulated by human menopausal gonadotropin.

Catechol estrogens, estrogen metabolites of potential physiologic significance, were measured in infertile women undergoing ovulation induction with human menopausal gonadotropins. Urinary 2-hydroxyestrone (2-OH-E1) specimens were obtained from 12 women in one or more stimulated cycles. The actual time for the administration of human chorionic gonadotropin to induce ovulation was based on serial plasma estradiol (E2) specimens. A significant correlation between plasma E2 and urinary 2-OH-E1 was demonstrated, similar but more pronounced than that seen in normal cycling women. This confirms previous work that showed that 2-OH-E1 is the major urinary estrogen metabolite in the nonpregnant state and further suggests that urinary catechol estrogens are a useful index of ovarian function.

Estradiol↗
PubMed1983

Radioimmunoassay of 2-hydroxyestrone in plasma during the estrous cycle of the rat: interrelationships with estradiol, progesterone, and the gonadotropins.

A RIA for 2-hydroxyestrone (2-OHE1) in rat plasma has been developed. The assay employs an antiserum that is specific for catechol estrogens. Specificity is further ensured by purification of plasma extracts on Sephadex LH-20 columns before RIA. Blood was collected at 0 C in the presence of ascorbic acid to prevent oxidation. Under these conditions, the conversion of 2-OHE1 to methylated derivatives was found to be negligible. Plasma 2-OHE1, LH, FSH, PRL, estradiol, and progesterone were measured at 3-h intervals throughout the 4-day estrous cycle of the rat. The 2-OHE1 concentration varied from undetectable to 11 pg/ml plasma. No clearly defined relationship with the other hormones analyzed was observed. Thus, it is unlikely that changes in circulating 2-OHE1 levels are involved in the regulation of the gonadotropin surge and ovulation.

Animals↗
PubMed1979

Deuterium-labeled steroids for study in humans. II. Preliminary studies on estrogen production rates in pre- and post-menopausal women.

6,7-Dideuterio-3-hydroxy-1,3,5(10)-estratrien-17-one (dideuterio-estrone) and 4-deuterio-1,3,5(10)-estratriene-3,17 beta-diol (monodeuterio-17 beta-estradiol) were used for the estimation of estrogen production rates in pre- and post-menopausal women. The results are concordant with those obtained by radioisotope administration as reported in the literature. This preliminary study suggests that one or more steroids labeled with one or multiple deuterium and/or other stable isotopes may be employed for the measurement of production rates of steroid hormones which are derived from multiple precursors.

Adult↗
PubMed1978

A radioimmunoassay method for urinary catechol estrogens.

A radioimmunoassay method for urinary catechol estrogens is described; The specific nature of the antisera allows direct analyses of acid hydrolyzed urine. A LH-20 Sephadex column chromatography can be employed for individual determinations of 2-hydroxyestrone and 2-hydroxyestradiol. The excretion of catechol estrogens during menstrual cycles ranged from 14.48 to 50.15 microgram per 24 hours, whereas, during the last trimester of pregnancies, the values ranged from 129.30 to 1758. 20 microgram per 24 hours.

Antibody Specificity↗
PubMed1976

The significance of urinary free cortisol and progesterone in normal and anencephalic pregnancy.

Urinary free cortisol and progesterone were determined by radioimmunoassay in 18 normal and 16 anencephalic pregnancies and urinary free cortisol levels in 9 nonpregnant women. In normal pregnancy the urinary free cortisol (46.89 +/- 34.02 mug per 24 hours) was significantly higher (P less than 0.001) than that found with anencephaly (17.19 +/- 13.20 mug per 24 hours) and 2 1/2 times (P less than 0.001) the nonpregnant value (18.47 +/- 5.44 mug per 24 hours). In 12 of the anencephalic pregnancies, urinary free cortisol levels (11.05 +/- 5.56 mug per 24 hours) were significantly lower than in nonpregnant women (P less than 0.001). Urinary progesterone levels in normal pregnancy (15.57 +/- 9.66 mug per 24 hours) and anencephaly (18.54 +/- 12.69 mug per 24 hours) were comparable. The cortisol excretion values associated with anencephaly indicate that the normal fetus contributes substantially to the maternal plasma cortisol pool. Urinary free cortisol determinations may be a useful index of fetal adrenal dysfunction.

Adrenal Glands↗
PubMed1976

Urinary progesterone as an index of ovulation and corpus luteal function.

Urinary excretions of progesterone (P) during normal menstrual cycle have been measured by radioimmunoassay. The excretion pattern mimics that of plasma P. Measurements of P in a single voided urine may be a reliable substitute for plasma analyses in the evaluation of ovulation and corpus luteal function.

Corpus Luteum↗