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C J Munro

Publications and source records attributed to C J Munro.

14 recordsLinked to original sources
PubMed1997

Steroid-level response to insulin-like growth factor-1 in oocytes matured in vitro.

The objective was to establish the influence of insulin-like growth factor-1 (IGF-1) on steroid production and nuclear maturation during oocyte in vitro maturation (IVM). Immature-selected rabbit follicular oocytes, divided as cumulus-oocyte complexes (COC) and denuded oocytes (DO), were cultured in Brackett's medium with different concentrations of IGF-1 at 0, 50, 100 and 200 ng/ml. After 8 and 16 h of culture, the oocytes were assessed for nuclear maturation by acetic-orcein stain, and media were analyzed by enzyme-immunoassay (EIA) for 17 beta-estradiol (E), progesterone (P), androstenedione (A) and testosterone (T) content. After culture treatments with IGF-1 significantly increased (P < 0.01) the incidence of nuclear activation (germinal vesicle breakdown stage, GVBD) and nuclear maturation (metaphase II stage); maximum stimulation occurred at 100 ng IGF-1/ml (86.9 vs. 49.3% in control). Compared to controls, the presence of IGF-1 in cultures was associated with a significant increase of E and A production by COCs (P < 0.01). However, P and T levels were not significantly influenced by the IGF-1. In addition, positive correlations between E/T and E/A ratios and nuclear maturation rates were only found in the IGF-1 treatments. Regarding the DOs, neither positive effects in nuclear maturation rates nor increase of steroid levels in culture were observed for any treatment. These results suggest that: (1) IGF-1 had a significant effect on E and A production during oocyte maturation; (2) the addition of IGF-1 enhanced nuclear maturation significantly in rabbit oocytes; and (3) all these effects are only possible in oocytes surrounded by cumulus cells.

Androstenedione↗
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↗
PubMed1996

An enzyme immunoassay for serum and urinary levonorgestrel in human and non-human primates.

A microtiter plate enzyme immunoassay (EIA) is reported for the measurement of levonorgestrel (LNG) in serum and urine samples of human and non-human primates, and the results are compared to data obtained by radioimmunoassay (RIA). Rabbit polyclonal antibodies were raised against the bovine serum albumin conjugate of the 3-O-carboxymethyl oxime (CMO) derivative of LNG. The enzyme label was produced by the conjugation of horseradish peroxidase to LNG at the 3-position by the same CMO bridge used for the immunogen. The assay requires 2.5 hours to perform using 2.2-azino-di-(3-ethylbenzthiazoline sulfonic acid) diammonium salt as the chromogenic substrate. Serum (100 microliters) is extracted with petroleum ether prior to assay, whereas urine samples (25 microliters) are diluted and measured directly. The sensitivity of the assay is 0.25 pg/well with a 50% displacement of label at 7.5-9.5 pg and a linear response through 250 pg/well. Minimum levels of 8.7 and 10.0 pg/ml can be detected in serum and urine samples, respectively. Changes in serum LNG concentrations were measured in women and non-human primates following LNG implantation or injection. In the non-human primate study, serum LNG concentrations began to rise rapidly following i.m. injection of LNG, with peak levels occurring on days 3 to 5, then decreasing to approximately 25-35% of peak levels for the duration of the study. Circulating concentrations of 1.86 +/- 0.18 ng/ml LNG were reached in women the first week post-insertion of Norplant implants and decreased by 50% at 7-10 days, 75% after 14-21 days, followed by a steady decrease during the next 60-70 days to constant low levels that exhibited a high individual variation. Correlation coefficients of EIA and RIA results were 0.988 for human serum, 0.926 for human urine, and 0.972 for non-human primate serum.

Adolescent↗
PubMed1996

Development of a simple, rapid sandwich enzyme immunoassay for the measurement of serum rat LH.

The present study describes the development and validation of a rapid, sensitive, specific and precise enzyme immunoassay (EIA) sandwich suitable for measuring luteinizing hormone (LH) in rat serum. Ninety-six well polystyrene microtiter plates were coated with 100 microliters (250 ng/ml) of a well-characterized monoclonal antibody (518B7, Roser, UC Davis) generated against bovine LH. A polyclonal antiserum raised in rabbits against ovine FSH (G4-215B, Papkoff) was conjugated to sodium periodate-activated horseradish peroxidase (HRP), and used as the second antibody of the sandwich assay. This anti-ovine FSH antiserum cross-reacted more than 200% with rat LH. Standards (r-LH-RP-3, NIADDK, range 0 pg/well to 2.5 ng/well or 100 microliters) diluted in a 3(N-Morpholino) propane sulfonic acid (MOPS) buffer, or serum, were incubated with the solid phase antibody for 2 hours. Plates were washed and the anti-oFSH:HRP (100 microliters) in MOPS buffer was added and incubated a further 2 hours before a second wash and the addition of the substrate (TMB, 3,3',5,5'-tetramethylbenzidine dihydrochloride and H2O2). The least detectable concentration of LH was 16.1 +/- 1.42 pg/ml. The recovery of known concentrations of LH added to several samples was 93.5 +/- 1.70%. Mean intra-assay and inter-assay coefficients of variation (%) were less than 10% (n = 20). The anti-FSH:HRP showed less than 8.0% cross reactivity with rFSH in this LH EIA system. The correlation coefficient (r) of samples analyzed by EIA in parallel with RIA was r = 0.90 (p < 0.001, n = 26). Results showed levels between 105.21 and 633.87 pg/ml. This new LH EIA sandwich offers a stable, rapid, and improved EIA system for the measurement of serum LH concentrations of this species over previously reported methods.

Animals↗
PubMed1991

A prototype for ovulation detection: pros and cons.

A noninstrumented enzyme immunoassay for urinary estrone conjugates was adapted from an instrumented microtiter plate enzyme immunoassay assay. The end point of the assay was a color change from green to clear, which was visible to the unaided eye. The visible color change was adjusted to allow 80 ng/ml estrone conjugates (on the basis of a sample size of 6.5 microliters urine) to be distinguished from an infinite dilution without instrumentation. The evaluation of human urine collected from ovulatory ovarian cycles demonstrated that early follicular phase concentrations (35.9 +/- 6.8 to 79.4 +/- 14.7 ng/ml, n = 10) produced a dark-green color, whereas late follicular phase concentrations (162.9 +/- 20.1 ng/ml, n = 10) produced no color. Daily urine samples throughout 10 ovulatory ovarian cycles produced parallel profiles when compared to measurements of estradiol in paired blood samples. Complete analysis of the data indicated that ovarian follicular dynamics can be accurately monitored through the noninstrumented analysis of daily estrone conjugates in urine samples.

Adult↗
PubMed1991

An oestrogen conjugate enzyme immunoassay for monitoring pregnancy in the mare: limitations of the assay between days 40 and 70 of gestation.

A direct enzyme immunoassay was developed to measure conjugated oestrogens in the plasma of pregnant mares. The antibody was produced in rabbits using oestrone-3-glucuronide (E1G) conjugated to bovine serum albumin. The enzyme conjugate was E1G conjugated to horseradish peroxidase. A sharp increase in plasma E1G concentrations occurred between Days 35 and 40 of gestation. Values declined slightly to Day 45, remained relatively constant to around Day 70 and rose sharply thereafter. Fetal death before Day 35 had no effect on plasma concentrations of E1G. Fetal death after Day 35 in conjunction with endotoxin-induced regression of the corpus luteum (CL) resulted in a decrease in plasma E1G levels to non-pregnant values within 3-4 days. Endotoxaemia without fetal death between Days 35 and 70 resulted in marked, but transient, decreases in plasma E1G concentrations. Fetal death without CL regression after Day 35 did not produce an immediate decline in plasma E1G concentrations and existing levels were maintained for 10-14 days. These findings indicate that between Days 35 and 70 of pregnancy, plasma E1G concentrations are not directly correlated with fetal viability; they appear to reflect increased oestrogen secretion by the CL under the influence of chorionic gonadotropin. After Day 70, E1G concentrations begin to reflect directly the production of oestrogen by the developing feto-placental unit.

Animals↗
PubMed1991

Relationship of serum estradiol and progesterone concentrations to the excretion profiles of their major urinary metabolites as measured by enzyme immunoassay and radioimmunoassay.

Paired daily blood and urine samples were collected from 10 apparently healthy premenopausal women to compare the hormone profiles of estradiol (E2) and progesterone in serum with those of estrone conjugates (E1Conj) and pregnanediol-3-glucuronide (PdG) in urine. Serum hormones were measured by radioimmunoassay (RIA) kits, whereas the urinary steroid metabolites were assessed by both RIA and enzyme immunoassay (EIA). RIA and EIA values for urinary E1Conj and PdG were not different, and both methods produced urinary profiles that paralleled the profile of the parent steroid in serum. However, the simplicity, flexibility, and economy of EIA will make this method more widely applicable. Mean E1Conj values lagged behind concentrations of serum E2 by one day or less, whereas daily urinary PdG profiles lagged behind serum progesterone by one to two days. Mean urinary profiles of E1Conj were similar whether or not creatinine was used to adjust for urine volume; however, creatinine indexing was beneficial when urinary profiles in individual cycles were compared with changes of serum E2.

Adult↗
PubMed1982

Prolactin response in beef cows and heifers suckling one or two calves.

Blood was collected, at 5-min intervals for 3 h, via jugular cannulation every 14 days during the first 4 months post partum from beef cows and heifers, 4 suckling 2 calves and 4 suckling 1 calf. Calves were isolated from the dams to prevent suckling for approximately 4 h before and 2 1/2 h during sampling to obtain baseline values for prolactin, measured by radioimmunoassay. During the last 30 min of sampling, calves were allowed to suck. Milk samples were also collected at 28-day intervals from 60 females, 30 with twins and 30 with single calves. beginning 2 weeks after calving and continuing until calves were weaned at 180 days of age. No differences were observed between dams with 1 and 2 calves for baseline plasma prolactin level or for prolactin response to the suckling stimulus by 1 or 2 calves. However, milk prolactin concentration was significantly higher (P less than 0.01) for dams with 2 calves, probably reflecting the more frequent suckling that occurs with twins. Milk prolactin value in this study was not highly correlated with the post-partum interval to first ovulation from another study on these animals. It is concluded that prolactin is not significantly higher (P less than 0.01) for dams with 2 calves, probably reflecting the more frequent suckling that occurs with twins. Milk prolactin value in this study was not highly correlated with the post-partum interval to first ovulation from another study on these animals. It is concluded that prolactin is not significantly higher (P less than 0.01) for dams with 2 calves, probably reflecting the more frequent suckling that occurs with twins. Milk prolactin value in this study was not highly correlated with the post-partum interval to first ovulation from another study on these animals. It is concluded that prolactin is not the primary factor controlling the longer post-partum interval to first ovulation in beef cattle with twins.

Animals↗
PubMed1981

Photoperiod induction of fertile oestrus and changes in LH and progesterone concentrations in yearling dairy goats (Capra hircus).

Oestrus and ovulation were induced in a group of 19 yearling dairy goats which had been maintained for 70 days on a 19 h/day photoperiod regimen. Six yearling females, raised under natural photoperiod, served as controls. An intact, light-treated male was introduced to each group 42 days after termination of the artificial lighting. Behavioural, endocrine and kidding observations indicated that 15 of the experimental females (79%) ovulated within 21-30 days after introduction of the male, that 12 (63%) conceived at the induced ovulation, and that 10 (53%) gave birth to live kids, while none of the controls ovulated during this time. The breeding season was advanced between 60 and 80 days. In experimental and control nannies there was a brief, small surge (320 +/- 42 pg/ml) of plasma progesterone which occurred 19.5 days after introduction of the male and which closely preceded oestrus in the nannies that ovulated and at 25 days in control females. Ovulatory surges of LH (to 70 ng/ml plasma) were closely associated with oestrus, and remained above basal levels for 9.0 +/- 0.75 h, in 7 experimental females. Two of 6 control nannies also showed LH surges but they did not ovulate.

Animals↗