Biomedical subjects

B L Lasley

Publications and source records attributed to B L Lasley.

At least 37 records · Page 2Linked to original sources

PubMed2000

Anti-nidatory effect of vaginally administered (Ala8,13, 18)-magainin II amide in the rhesus monkey.

The hypothesis that timed application of a potent anti-microbial, anti-tumor agent like magainin peptides can inhibit blastocyst implantation was examined in the present study using the rhesus monkey as the primate model. Incidence of pregnancy, vaginal bleeding patterns, serum levels of progesterone, estrogen and monkey chorionic gonadotropin were examined following vaginal administration of (Ala8,13,18)-magainin II amide, a synthetic analogue of magainin 2, via tampon during days 20 to 26 of mated cycles. Implantation occurred in two out of three animals following administration of 0.25 mg magainin, while administration of 0.5 mg (Ala8,13,18)-magainin II amide resulted in inhibition of implantation in all females with no change in lengths of treatment cycles, and subsequent cycles. It appears from the present study that, besides being a local microbicidal agent, intravaginal administration of (Ala(8,13,18))-magainin II amide is a potential anti-implantation strategy for intercepting pregnancy.

Administration, Intravaginal↗

PubMed2000

Anti-nidatory effect of vaginally administered fumagillin in the rhesus monkey.

In the present study, fumagillin, which is an antibiotic with potent angiostatic activity secreted from Aspergillus fumigatus was administered intravaginally during peri-implantation stage in the rhesus monkey and its effects on ovarian function, blastocyst implantation and pregnancy outcome in the rhesus monkey were investigated. Female monkeys (n = 18) showing normal menstrual cycles were vaginally inserted with tampons containing fumagillin (0 mg/animal in group 1; 1 mg/animal in group 2; 2 mg/animal in group 3; 4 mg/animal in group 4) on cycle day 20 of the mated treatment cycle, and these were removed on day 26 of the treatment cycle. Pregnancy was found to occur in animals treated with 1 mg and 2 mg fumagillin. However, animals treated with 4 mg fumagillin remained non-pregnant along with decreased (p <0.001) concentration of progesterone in circulation during the luteal period compared with that in normal, non-mated, ovulatory cycle.

Administration, Intravaginal↗

PubMed2000

Effects of progesterone receptor blockers on human granulosa-luteal cell culture secretion of progesterone, estradiol, and relaxin.

We have developed culture methods for human luteinizing granulosa cells (GLC) that support the timely and dynamic secretion of estrogen (estradiol-17beta; E(2)), progesterone (P(4)), and relaxin (Rlx) in patterns that mimic serum hormone concentrations during the luteal phase of the menstrual cycle. Additional hCG, to simulate rescue of the corpus luteum, prevented the normal decline in GLC hormone production. To test the importance of the P(4) receptor in P(4) production, GLC were treated in vitro with two P(4) receptor antagonists. Human GLC received one of two hCG support protocols: a Baseline group simulating the normal luteal phase or a Rescue group simulating early pregnancy. Baseline and Rescue groups were treated with either RU-486 or HRP2000 either early or late in the cell culture period. The effects of treatments or control on ovarian steroid and peptide hormone production were determined (significant difference was P < 0.05). In the Rescue group, late treatment resulted in an immediate and dramatic decline in E(2), P(4), and Rlx secretion to nearly nondetectable levels within 1 day after treatment, and hormones remained depressed for the remaining 10 days of culture. In contrast, early treatment resulted in a decline in steroid hormone secretion that returned to control levels within 5 days of cessation of treatment, and Rlx secretion was delayed for approximately 5 days more than in controls. The data support the hypothesis that P(4) may be a required autocrine factor, not only for its own production but also for the maintenance of full endocrine function of the corpus luteum.

Cells, Cultured↗

PubMed2000

2,3,7,8-tetrachlorodibenzo-p-dioxin decreases estradiol production without altering the enzyme activity of cytochrome P450 aromatase of human luteinized granulosa cells in vitro.

This study was designed to examine the in vitro effects of 2,3,7, 8-tetrachlorodibenzo-p-dioxin (TCDD) on steroid production in human luteinizing granulosa cells (hLGC). TCDD (10 nM) or its solvent was added at the time of changing medium, directly to the cells, every 48 h for 8 days. To test the hypothesis that TCDD reduces estradiol (E(2)) synthesis by an effect on cytochrome P450 aromatase, aromatase protein and aromatase activity were evaluated. E(2) decreased without changing either aromatase protein or its enzyme activity, suggesting that the target of toxicity of TCDD is upstream of aromatase in the steroidogenic pathway. When hLGC were incubated in the presence of labeled E(2), no changes in the metabolism of E(2) by treatment were observed. Since TCDD did not change progesterone or 17alpha-hydroxyprogesterone, the inhibition of E(2) synthesis by TCDD would seem not to involve steps such as cholesterol transport. Furthermore, the TCDD effect on E(2) concentration in these cells disappeared in the presence of excess androgens. We conclude that the inhibition of E(2) secretion by TCDD involves intermediate steps, specifically, the provision of androgens for aromatization.

17-alpha-Hydroxyprogesterone↗

PubMed1999

Application of an enzyme immunoassay for urinary follicle-stimulating hormone to describe the effects of an acute stressor at different stages of the menstrual cycle in female laboratory macaques.

An enzyme-linked immunosorbent assay (ELISA) for human urinary beta follicle-stimulating hormone (FSH) subunit was validated for use in the laboratory macaque (Macaca mulatta and Macaca fasicularis). This ELISA is based on the dissociation of the FSH heterodimer in urine and the subsequent measurement of the beta subunit as a representation of total urinary FSH. This assay was then used to describe the gonadotropin escape following ovarian senescence in post-menopausal macaques. In addition, the assay was used to observe the impact of an acute stressor on the pituitary-gonadal axis and how the impact of this stressor varies when experienced at different stages of the menstrual cycle. The study design involved the measurement of ovarian steroids and FSH in urine collected daily during a period of time when animals experienced a well-defined event on two occasions consisting of capture, restraint, and anesthesia. This unique study design was made possible by the ability to monitor both ovarian and pituitary function in the absence of confounding daily captures and restraint for blood collection. There was a high correlation between urinary FSH measured in macaques with the beta FSH subunit ELISA and serum FSH measured in paired blood samples by radioimmunoassay (n=39, r2=0.878, P<0.001) and the composite urinary FSH profile obtained from normal, premenopausal macaques exhibited the expected dynamics with a transient rise of FSH during the luteal-follicular transition as well as an acute rise of FSH at mid-cycle. This pattern was lost in castrate and post-menopausal monkeys in which FSH levels were significantly increased (P<0.0001) above those of intact males and young females, respectively. In the stress study, we found that stressors occurring during the luteal-follicular transition not only resulted in acute perturbations of FSH but also led to abnormalities in the subsequent menstrual cycle in 50% of the cases.

Animals↗

PubMed1999

Studies on the origin of ovarian interstitial tissue and the incidence of endometrial hyperplasia in domestic and feral cats.

Ovarian interstitial cells (OICs) are a common feature of mammalian gonads but little is understood concerning their origin or functional significance. This study investigated the development and steroidogenic potential of OIC in feral and colony-reared feline queens. Reproductive tracts, collected from a total of 50 female colony and feral cats, were fixed and analyzed by morphometry. Ovarian sections were also immuno-stained for the expression of the steroidogenic enzymes 17alpha-hydroxylase/17,20 lyase cytochrome P450 (P450c17), 3beta-hydroxysteroid dehydrogenase/Delta5-Delta4 isomerase (3beta-HSD), and aromatase. These findings were related to serum estradiol and testosterone concentrations and to the degree of existing cystic endometrial hyperplasia (CEH). Feral cats had three times as many OICs as colony-reared queens (2713 +/- 855 vs 744 +/- 494 cells/mm(2), P < 0.01). These cells were lipid laden and expressed both P450c17 and 3beta-HSD at levels that were higher than those seen in the theca interna of adjacent follicles. Aromatase expression was undetectable. The pattern of enzyme expression was consistent with development of interstitial tissue from atretic follicles and the potential for continued steroid secretion during the anestrum. The incidence of CEH was higher in older (>5 years old; 88.2%) than in younger (2-4 years; 30%) colony queens (P < 0. 01), whereas no such disease was evident in any of the feral cats. Estradiol levels were higher in colony-reared than in feral cats, but testosterone levels were not different. These data are consistent with the transformation of the theca interna of atretic follicles in cats into OICs that retain a similar, or even enhanced, steroidogenic phenotype. Colony-reared cats exhibit a predisposition to CEH compared with feral queens that is associated with elevated serum estradiol concentrations. Whether or not OICs somehow prevent the development of uterine disease or otherwise reflect a gonadal response to reduced negative feedback on the hypothalamic-pituitary axis remains to be determined.

3-Hydroxysteroid Dehydrogenases↗

PubMed1999

Endocrine biomarkers of early fetal loss in cynomolgus macaques (Macaca fascicularis) following exposure to dioxin.

This study examines the endocrine alterations associated with early fetal loss (EFL) induced by an environmental toxin, TCDD (2,3,7, 8-tetrachlorodibenzo-p-dioxin), in the cynomolgus macaque, a well-documented reproductive/developmental model for humans. Females were administered single doses of 1, 2, and 4 microgram/kg TCDD (n = 4 per dose group) on gestational day (GD) 12. Urinary estrogen metabolites (estrone conjugates) were monitored to establish the day of ovulation, and serum hormones (estradiol, progesterone, chorionic gonadotropin, relaxin) were measured to assess ovarian and placental endocrine status before and after treatment. EFL occurred between GDs 22 and 32 in 10 of the 12 animals treated with TCDD. The primary endocrine alterations associated with TCDD treatment were significant decreases in serum estradiol and bioactive chorionic gonadotropin concentrations (p < 0.02). Less pronounced decreases in serum progesterone (p = 0.10) and relaxin (p < 0.08) also followed TCDD treatment. In contrast, immunoreactive chorionic gonadotropin concentrations were not reduced by TCDD exposure at any level, indicating that TCDD targets specific components of the chorionic gonadotropin synthesis machinery within the trophoblast to alter the functional capacity of the hormone. These data demonstrate the value of endocrine biomarkers in identifying a toxic exposure to primate pregnancy many days before direct signs of reproductive toxicity were apparent. The increased EFL that occurred after exposure to TCDD might reflect a toxic response initially mediated via endocrine imbalance, leading to placental insufficiency, compromised embryonic circulation, and subsequent EFL.

Abortion, Spontaneous↗

PubMed1999

Urinary follicle stimulating hormone can be used as a biomarker to assess male reproductive function.

AIM: To develop an algorithm for use in population-based studies to assess testicular function by measurements of total urinary follicle stimulating hormone (FSH). METHODS: Total concentrations of urinary FSH were measured in a group of 44 men at the University of California, Davis (UCD) and were compared to FSH measurements in serum. On the basis of these and other published data, a urinary FSH value of >2 ng/mg creatinine (Cr) was selected as the cutoff point to identify men with elevated serum FSH ( > 12 IU/L) or low sperm counts ( < 20 million/mL). RESULTS: The sensitivity and specificity of this algorithm for detecting elevated serum FSH in a group of 58 agricultural workers in the People' s Republic of China were 100% and 50%, respectively. The sensitivity and specificity of this algorithm for detecting low sperm counts in a population of 105 infertility patients at UCD were 58 % and 76 %, respectively. CONCLUSION: This test may have particular value in identifying populations with no evidence of testicular toxicity, and in which labor-intensive semen studies may not be feasible.

Biomarkers↗

PubMed1998

Pregnancy-specific elevations in fecal concentrations of estradiol, testosterone and progesterone in the domestic dog (Canis familiaris).

Estradiol (E2), testosterone (T) and progesterone (P4) concentrations were determined by enzyme-immunoassay in aqueous extracts of fecal samples obtained during anestrus, proestrus, estrus and metestrus of 11 nonpregnant and 11 pregnant bitches. Fecal hormone concentrations (ng/g) changed in relation to stage of cycle. Mean fecal steroid concentrations in 22 anestrous bitches and 3 ovariectomized bitches were low and similar for E2 (53 +/- 5 and 27 +/- 2), T (60 +/- 7 and 36 +/- 6), and P4 (62 +/- 6 and 86 +/- 15). Within 0 to 3 d of the ovulatory LH surge fecal E2 reached peak concentrations (301 +/- 38). The T peaks (281 +/- 41) were coincident or 1 to 3 d later. Fecal P4 was then elevated for approximately 2 m.o. Between Days 26 and 45 after ovulation, mean fecal P4 concentrations were higher (P < 0.05) in pregnant (401 +/- 60) than in nonpregnant bitches (164 +/- 23) and peak fecal P4 concentrations in individual animals were higher (P < 0.01) in pregnant (812 +/- 121) than in nonpregnant bitches (425 +/- 97). In the same period mean concentrations of E2 (117 +/- 13 vs 61 +/- 5) and T (102 +/- 10 vs 70 +/- 6) were also higher (P < or = 0.05) in pregnant than in nonpregnant bitches. Serum E2, T and P4 concentration were positively correlated (P = 0.1) with concentration in fecal samples obtained one day after serum collection. Although serial fecal ovarian steroid concentrations demonstrate the time course of ovulatory cycles, the diagnostic value of individual fecal samples appears limited. The ratios of peak to basal values were approximately 6, 5 and 7 for E2, T and P4, respectively, and were considerably lower than ratios of 12 to 50 previously reported for serum or plasma concentrations. The results demonstrate that there are pregnancy-specific increases in P4, E2 and T production reflected in fecal concentrations. While such increases are reflected in fecal samples, they are generally not evident in serum or plasma concentrations because of increased hemodilution, metabolism and clearance in pregnant bitches. The physiological stimulus for these increases, presumably ovarian in origin, or the potential role of prolactin is not known.

Animals↗

PubMed1998

Use of urine biomarkers to evaluate menstrual function in healthy premenopausal women.

A total of 403 healthy, premenopausal women, residing near Santa Clara, California, were recruited from a large health care plan in California for a study of menstrual function. After a telephone interview, participants collected daily urine samples and recorded bleeding and other information in diaries. Data were collected during 1990-1991. Urine samples were analyzed for creatinine and for estradiol and progesterone metabolites by enzyme-linked immunoassay. Computer algorithms were developed to derive menstrual segment length, ovulatory status, day of ovulation, and other parameters from the urine and diary data. (We use "segment" rather than "cycle" to avoid implying that normal cycling occurred.) The average length of participation was 141 (standard deviation, 45) days. The mean segment length was 28.8 (standard deviation, 4.4) days; follicular phase length, 16.0 (standard deviation, 4.4) days; and luteal phase length, 12.9 (standard deviation, 1.7) days; 19 (4.7%) women experienced anovulatory episodes. In exploratory multivariate analyses, important associations included the following: age of > or = 35 years with decreased segment and follicular phase lengths; heavier weight (upper quartile) with anovulation and increased follicular phase and decreased luteal phase lengths; Hispanic ethnicity with anovulation and increased segment length; and past difficulty in achieving pregnancy with anovulation and increased length and variability of segments and follicular phases. Urine biomarkers can be used successfully to evaluate menstrual function in epidemiologic studies.

Adult↗

PubMed1998

Enzyme immunoassay method for total urinary follicle-stimulating hormone (FSH) beta subunit and its application for measurement of total urinary FSH.

OBJECTIVE: To develop and validate an enzyme-linked immunosorbent assay (ELISA) for total urinary follicle-stimulating hormone (FSH) that can be used to evaluate frozen-thawed urine samples. DESIGN: A method was developed for dissociating urinary FSH into subunits by boiling. An ELISA for the free beta subunit of FSH was used to measure total FSH in urine samples collected from male and female volunteers. The urinary FSH values were compared with serum FSH concentrations in paired samples. SETTING: A clinical research laboratory. PATIENT(S): Serum and urine samples from normal male and female volunteers and from men with infertility were used to develop and validate an assay for total urinary FSH. INTERVENTION(S): None. RESULT(S): Urinary FSH concentrations in frozen-thawed urine were highly correlated to matched serum FSH concentrations. CONCLUSION(S): A microtiter plate ELISA for FSH beta subunit provides an economical method for evaluating FSH secretion in men and women. This method has practical applications for population-based epidemiologic studies in which urine samples are collected in the field and stored frozen before analysis.

Adult↗

PubMed1998

Maternal serum androgens in human pregnancy: early increases within the cycle of conception.

Previous studies have demonstrated elevations in testosterone and androstenedione initiated within the cycle of conception in pregnant non-human primates, and minimal data in the human support the same picture. In the present study we have investigated a group of patients scheduled for artificial insemination with regular menstrual cycles. For this study all patients provided blood samples at 5 days after the luteinizing hormone (LH) surges and daily through the luteal phase and into early pregnancy (n = 12). Patients who did not become pregnant served as normal controls (n = 9). We have measured 17-hydroxyprogesterone (17-OHP) as a marker of luteal activity not obscured by progesterone within the cycle of conception and testosterone and androstenedione as the major androgens. There were no significant changes in testosterone and androstenedione in the non-pregnant controls, but both testosterone and androstenedione were significantly elevated in the pregnant luteal phase, with the first increases occurring at 15 and 14 days respectively after the LH surge. Three of 12 pregnant patients did not demonstrate a dramatic increase in either testosterone or androstenedione and when examined more carefully a corresponding lack of increase in 17-OHP in those same subjects indicated less than optimal luteal activity, suggesting that these androgens were products of the corpus luteum. In three subjects in which consecutive non-pregnant and pregnant cycles were followed there was a dramatic increase from the non-pregnant luteal phase to the pregnant luteal phase indicating that the more important observation may be the concentrations of androgens in the conceptive luteal phase compared to some baseline, either previous luteal phase or even follicular phase. We have also studied changes in dehydroepiandrosterone sulphate and found that there was no significant contribution to this increase in androgens in early conception. These studies demonstrate a significant increase in both testosterone and androstenedione presumably of ovarian, specifically luteal, origin and that adrenal androgen production is not a factor in these changes.

17-alpha-Hydroxyprogesterone↗

PubMed1998

Development and validation of a fecal testosterone biomarker in Mus musculus and Peromyscus maniculatus.

This is a report on the development and validation of an ELISA method to determine fecal testosterone levels, and on their evaluation as a biomarker for adverse effects of endocrine-disrupting chemicals on reproductive health using male rodents of the Peromyscus maniculatus and Mus musculus species as an animal model. The ELISA antibody had the highest specificity for testosterone (100%), followed by dihydrotestosterone (57.4%) and androstenediol (0.27%). Radiolabeled testosterone was injected i.p. into three mice. Fecal samples were collected, extracted, and analyzed by liquid scintillation counting. The ELISA was performed to characterize the excretion kinetics and metabolic fate of circulating testosterone. Solubilization of feces with 10% methanol overnight provided an extraction efficiency of 87% for all metabolites; an ethyl ether extraction was more selective for testosterone. The fecal excretion of the testosterone was a biphasic process with a majority of the radioactivity recovered in the first 24 hours. HPLC analysis revealed at least five testosterone metabolites in feces, with most metabolites being less polar than testosterone. This study forms the initial evaluation of what will become a field monitoring tool.

Androstenediol↗

PubMed1998

Reproductive hormone profile among pesticide factory workers.

Serum follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone levels, as well as urinary levels of FSH, LH, and E1C, a metabolite of testosterone, were measured to investigate the adverse reproductive effects of organophosphate pesticides among Chinese factory workers who were occupationally exposed to ethylparathion and methamidophos. Thirty-four exposed workers were randomly chosen and recruited from a large pesticide factory, and 44 unexposed workers were selected from a nearby textile factory. A quantitative pesticide exposure assessment was performed among a subset of the exposed and unexposed workers. Information on potential confounders was collected in an interview. A single blood sample was collected at the end of a work shift, when each subject also donated a semen sample. Three first-voided urine samples were collected from each worker on 3 consecutive days. Urinary p-nitrophenol level at 1 hour after the work shift correlated with serum (r = 0.71, P < 0.01) and urinary (r = 0.51, P = 0.04) FSH levels. Stratifying by the subjects' exposure status, we found a significant negative correlation among the exposed group between urinary FSH level and sperm count (r = -0.61, P < 0.01) and between urinary FSH level and sperm concentration (r = -0.53, P = 0.03). Pesticide exposure alone was significantly associated with serum LH level (beta [coefficient of exposure effect] = 0.79; 95% confidence interval [CI] = 0.42, 1.16) but not with serum FSH or testosterone or with any urinary hormone levels. With adjustment for age, rotating shift work, current cigarette smoking, and current alcohol consumption, exposure significantly increased the serum LH level by 1.1 mIU/mL (95% CI = 0.34, 1.82). Meanwhile, the serum FSH level was slightly elevated (beta [coefficient of exposure effect] = 1.38; 95% CI = -0.09, 2.85) and the serum testosterone level was decreased (beta = -55.13; 95% CI = -147.24, 37) with increased pesticide exposure. Age and rotating shift work appeared to act as confounders. We conclude that organophosphate pesticides have a small effect on male reproductive hormones, suggestive of a secondary hormonal disturbance after testicular damage.

Adult↗

PubMed1998

High frequency of luteal phase deficiency and anovulation in recreational women runners: blunted elevation in follicle-stimulating hormone observed during luteal-follicular transition.

The purposes of this investigation were to evaluate the characteristics of three consecutive menstrual cycles and to determine the frequency ofluteal phase deficiency (LPD) and anovulation in a sample of sedentary and moderately exercising, regularly menstruating women. For three consecutive menstrual cycles, subjects collected daily urine samples for analysis of FSH, estrone conjugates (E1C), pregnanediol-3-glucuronide (PdG), and creatinine (Cr). Sedentary (n=11) and exercising (n=24) groups were similar in age (27.0+/-1.3 yr), weight (60.3+/-3.1 kg), gynecological age (13.8+/-1.2 yr), and menstrual cycle length (28.3+/-0.8 days). Menstrual cycles were classified by endocrine data as ovulatory, LPD, or anovulatory. No sedentary women (0%) had inconsistent menstrual cycle classifications from cycle to cycle, but 46% of the exercising women were inconsistent. The sample prevalence of LPD in the exercising women was 48%, and the 3-month sample incidence was 79%. In the sedentary women, 90% of all menstrual cycles were ovulatory (SedOvul; n=28), whereas in the exercising women only 45% were ovulatory (ExOvul; n=30); 43% were LPD (ExLPD; n=28), and 12% were anovulatory (ExAnov; n=8). In ExLPD cycles, the follicular phase was significantly longer (17.9+/-0.7 days), and the luteal phase was significantly shorter (8.2+/-0.5 days) compared to ExOvul (14.8+/-0.9 and 12.9+/-0.3 days) and SedOvul (15.9+/-0.6 and 12.9+/-0.4 days) cycles. Luteal phase PdG excretion was lower (P < 0.001) in ExLPD (2.9+/-0.3 microg/mg Cr) and ExAnov (0.8+/-0.1 microg/mg Cr) cycles compared to SedOvul cycles (5.0+/-0.4 microg/mg Cr). ExOvul cycles also had less (P < 0.01) PdG excretion during the luteal phase (3.7+/-0.3 microg/mg Cr) than the SedOvul cycles. E1C excretion during follicular phase days 2-5 was lower (P=0.05) in ExOvul, ExLPD, and ExAnov cycles compared to SedOvul cycles and remained lower (P < 0.02) in the ExLPD and ExAnov cycles during days 6-12. The elevation in FSH during the luteal-follicular transition was lower (P < 0.007) in ExLPD (0.7+/-0.1 ng/mg Cr) cycles compared to SedOvul and ExOvul cycles (1.0+/-0.1 and 1.1+/-0.1 ng/mg Cr, respectively). Energy balance and energy availability were lower (P < 0.05) in ExAnov cycles than in other menstrual cycle categories. The blunted elevation in FSH during the luteal-follicular transition in exercising women with LPD may explain their lower follicular estradiol levels. These alterations in FSH may act in concert with disrupted LH pulsatility as a primary and proximate factor in the high frequency of luteal phase and ovulatory disturbances in regularly menstruating, exercising women.

Adolescent↗

PubMed1998

Biomarkers for assessing human female reproductive health, an interdisciplinary approach.

Identification of environmental hazards to reproductive health and characterization of the adverse outcomes necessitate a multidisciplinary approach. Epidemiologic studies are required for the identification of adverse health effects in human populations and then to confirm that specific exposures are responsible. Clinical studies are required to develop assays for reproductive biomarkers and to validate these assays prior to their application in the field. Assays for field use must be formatted and streamlined for large-scale applications and, whenever possible, computer algorithms should be developed to interpret biomarker data. Appropriate animal models must be identified, biomarker assays validated for that model, and animal experiments conducted to identify the mode of action and target organ of a putative reproductive toxicant. Finally, in vitro studies at the level of the cell and cell organelle are essential for mechanisms for toxicity to be clearly identified and understood. In this article we describe the interdisciplinary approach that we have developed for study of the effects of environmental agents on female reproductive functions. This effort requires specific skills of toxicologists, epidemiologists, physicians, biochemists, and physiologists.

Adult↗

PubMed1997

ELISA for the measurement of serum and urinary chorionic gonadotropin concentrations in the laboratory macaque.

A rapid, sensitive, enzyme-linked immunosorbant assay (ELISA) for the measurement of chorionic gonadotropin (CG) in serum and urine samples of laboratory macaques is reported. The ligand (CG) is captured by a readily available, widely used, and well-characterized monoclonal antibody (Mab, 518B7) generated against the beta subunit of bovine luteinizing hormone (LH). This Mab, while specific for LH, shows very little species specificity, and has been shown to detect LH and CG by radioimmunoassay (RIA) in both human and non-human primates. A polyclonal antiserum raised in rabbits against human chorionic gonadotropin (hCG) is conjugated to horseradish peroxidase, and is used as the second antibody signal. This anti-hCG antiserum cross reacts with CG secreted by both the human (hCG) and macaque (mCG). The ELISA utilizes hCG as the standard, and results are based on the relative concentrations of mCG in serum and urine. Total assay time is less than 5 hours. Range of the standard curve is 0.002 to 0.5 ng hCG/well, and the least detectable concentration of hCG is 0.0023 +/- 0.0007 ng/well. Pregnancy was detected in early pregnant macaques (M. fascicularis) on 9 (N = 1/16), 10 (N = 1/16), 11 (N = 1/16), 12 (N = 6/16), 13 (N = 1/16), 14 (N = 4/16), and 15 (N = 2/16) days following the pre-ovulatory urinary estrone conjugate peak. The detection of pregnancy by urinary mCG occurred approximately 24 to 72 hours after its detection in serum.

Animals↗

PubMed1997

Reproductive events of wild cotton-top tamarins (Saguinus oedipus) in Colombia.

Reproductive patterns of wild cotton-top tamarin (Saguinus oedipus) females located in La Reserva Forestal Protectora Serranía de Coraza-Montes de María in Colosó, Colombia, were examined using long-term behavioral observations and fecal steroid analysis. Using an enzyme immunoassay, we analyzed fecal samples for E1C and PdG. Comparisons of reproductive cycles of a reproductively active female and her daughters were made. An inhibition of ovarian cycles has been observed in daughters living in their families. However, daughters also exhibited normal ovarian cycling that subsequently resulted in pregnancy. Factors influencing the fertility are discussed as they relate to the reproductive strategies of wild cotton-top tamarin females.

Animals↗