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N M Czekala

Publications and source records attributed to N M Czekala.

33 records · Page 2Linked to original sources
PubMed1986

Monitoring gonadotropin-releasing hormone administration by measurement of urinary steroid conjugates.

The use of measuring urinary steroid conjugates in nontimed, randomly collected morning urine samples expressed as a function of creatinine concentration was assessed to monitor ovarian response to pulsatile administration of gonadotropin-releasing hormone in ambulatory patients. This method of evaluating ovarian steroid production provided a convenient, inexpensive, and noninvasive means of monitoring responses to gonadotropin-releasing hormone treatments and documents that clomiphene-resistant amenorrheic patients can be induced to ovulate with appropriate gonadotropin-releasing hormone therapy. Different ovarian responses in the same woman to similar doses and frequencies of gonadotropin-releasing hormone indicate that discrete adjustments of individual doses may be required to facilitate consistent ovulatory responses. The strategy presented here allows for subsequent gonadotropin-releasing hormone therapy in the individual patient to be determined by an objective and quantifiable ovarian response to an initial treatment.

Adult↗
PubMed1985

HPLC separation of anti-estrogen and estrogen receptor binding components of mouse plasma.

Proestrous mouse plasma and urine were subjected to diethyl ether extraction, enzyme hydrolysis and HPLC separation of estrogen components. Radioimmunoassay of the treated proestrous samples with a broad spectrum anti-estrogen serum failed to detect estradiol-17 beta, estrone or estriol. HPLC chromatograms contained two peaks of immunoreactive and estrogen receptor binding material with polarities between those of estriol and estradiol-17 beta. Similar peaks were detected in HPLC chromatograms of urinary extracts from ovariectomized and ovariectomized-adrenalectomized mice. The least polar of the two peaks produced a mass spectrum identical to that of authentic equol [7-hydroxy-3-(4'-hydroxyphenyl)chroman], a phytoestrogen metabolite. The presence of significant quantities of circulating equol in all strains studied, combined with apparently low plasma levels of endogenous classical estrogens during proestrus, confound attempts to study estrogen secretion in the mouse.

Animals↗
PubMed1984

Identification of a non-steroidal estrogen, equol, in the urine of pregnant macaques: correlation with steroidal estrogen excretion.

Macaque urinary estrogens at late pregnancy were separated by high performance liquid chromatography and quantified, both with radioimmunoassay and an in vitro uterine estrogen receptor assay. Five estrogens were measured. Four were steroids: estriol, estrone, 17 beta-estradiol, and 16 alpha-hydroxyestrone. The fifth was a flavonoid, equol, a metabolite of plant isoflavonoids, formononetin and genistein. By mass, estrone and equol were the predominant urinary estrogens, with equol reaching levels of microgram/mg creatinine in three of 8 pregnancies studied. Both quality and quantity of urinary estrogen excretion in the rhesus (Macaca mulatta) was compared to those in 4 other species (Macaca fascicularis, Macaca nemestrina, Macaca radiata and Macaca silenus). All 5 estrogens present in the rhesus were also present in the other 4. Variability in mass of each estrogen excreted appeared no greater between species than within the rhesus. In a longitudinal study, urinary equol levels were most highly correlated with those of estrone, the predominant excretory steroid of macaque pregnancy. We conclude endogenous steroidal estrogen is related to production of equol in macaques, however, equol is not dependent on the feto-placental unit as low levels of equol were also present in male macaque urine.

Animals↗
PubMed1983

Urinary estrogen excretion during pregnancy in the gorilla (Gorilla gorilla), orangutan (Pongo pygmaeus) and the human (Homo sapiens).

Urinary estrogen components were separated, identified and quantified throughout the pregnancy of the gorilla (Gorilla gorilla) and orangutan (Pongo pygmaeus) and compared to estrogen levels in normal human pregnancies. Fetal and neonatal adrenals from each species were also compared in terms of weight and relative amounts of fetal zone. The results demonstrate that gorillas and chimpanzees excrete 4- to 5-fold less estrogen during pregnancy than the human and orangutan which are similar to each other. The lower estrogen excretion appears to be related to a smaller fetal adrenal in both the gorilla and chimpanzee which reveal both a reduced adrenal weight and increased definitive to fetal zone ratio when compared to either the human or orangutan.

Adrenal Glands↗
PubMed1983

Urinary estrogens during pregnancy of the ruffed lemur (Lemur variegatus).

Pregnancy in the ruffed lemur (Lemur variegatus) was monitored by analyses of urinary estrogens. Urine samples were collected weekly throughout pregnancy (gestation: 100 +/- 1.6 days) from ten females analyzed for total immunoreactive estrogen (Et) and indexed by creatinine (Cr). Maternal urinary total estrogen excretion remained low until the last half of gestation at which time excretion increased steadily, reaching values 1000 times greater than those observed at estrus. Chromatographic separation after enzyme hydrolysis of lemur urine indicates that estrone is the major estrogenic component of pregnancy in the ruffed lemur, with the remaining components consisting of equal amounts of estradiol-17 alpha and -17 beta.

Animals↗
PubMed1983

Monitoring ovulation and implantation in the lion-tailed macaque (Macaca silenus) through urinary estrone conjugate evaluations.

Urine samples were collected daily during ten nonfertile and four fertile ovarian cycles of four adult female lion-tailed macaques (Macaca silenus). Urine was analyzed for concentrations of total immunoreactive estrogen (Et), estrone conjugates, and bioactive luteinizing hormones (LH). The estrone conjugates of selected samples were separated by high-performance liquid chromatography (HPLC) to evaluate the relative proportions of estrone glucuronide (E1 G) to estrone sulfate (E1 S) contributing to the sum total of the conjugate measured in the samples. The estrone conjugate profile was found to accurately reflect the preovulatory estrogen peak in both nonfertile and fertile cycles as well as the early pregnancy increase which was found to be statistically significant on Day + 14 postovulation (P = 0.003). Estrone conjugate levels rose in the early follicular phase from 126.00 +/- 24.07 (SEM) ng/mg creatinine to a preovulatory peak of 471.90 +/- 62.95 ng/mg creatinine. Fertile cycles exhibited a postovulatory climb to a peak of 515.00 +/- 38.00 ng/mg creatinine on Day + 19, in contrast to the secondary rise observed in nonfertile cycles that peaked at 148.11 +/- 13.80 ng/mg creatinine on Day + 10. Bioactive LH evaluations confirmed ovulation and, in the fertile cycles, reflected the subsequent elevation of chorionic gonadotropin on Day + 18. The estrone conjugate profile of fertile cycles and early pregnancy compared favorably to the Et profile: both showed the same time course and increases in estrogen excretion.

Animals↗
PubMed1982

Fetal-maternal gradients of steroid hormones in the nine-banded armadillo (Dasypus novemcinctus).

Gonadal and adrenal steroid hormone levels in plasma were measured in pregnant, non-pregnant and fetal armadillos. Progesterone demonstrated the largest placental gradient with levels 6 to 10-fold higher in the fetus. Testosterone levels were higher in male and lower in female fetuses, when compared to the respective maternal serum values. Dehydroepiandrosterone, and cortisol were consistently high in maternal as compared to matched fetal serum samples whereas the reverse was true for androstenedione. Tissue incubations with labelled pregnenolone indicated the major source of progesterone production to be the fetal adrenal whereas the fetal testes demonstrated a major conversion product consistent with dehydroepiandrosterone.

Animal Population Groups↗
PubMed1981

Pregnancy monitoring in diverse primate species by estrogen and bioactive luteinizing hormone determinations in small volumes of urine.

Immunoreactive estrogen and luteinizing hormone/chorionic gonadotropin (LH/CG) bioactivity have been measured throughout pregnancy in diverse primate species with a sample methodological approach utilizing small volumes of urine collected randomly. Total immunoreactive estrogen levels and the relative abundance of component estrogens (estrone, estradiol and estriol) at various stages of gestation were compared in the human, orangutan, pygmy chimpanzee, Douc langur and capuchin. Measurement of urinary LH/CG bioactivity enables an earlier detection of pregnancy when compared to the nonhuman primate pregnancy test. The methods described provide a practical and non-stressful way to detect and monitor pregnancy in widely divergent primate species.

Animals↗
PubMed1981

Comparison of urinary oestrogen excretion in South American primates.

Changes in the excretion of immunoreactive oestrogens and biologically active LH were assessed from measurements on small samples of urine collected from a capuchin, a tamarin, a spider monkey and a squirrel monkey. The hormone profiles were used to time matings of the capuchin and spider monkey; conception and pregnancy ensued. Detailed analysis of one urine sample from each female by using partition chromatography and reverse-phase high-pressure liquid chromatography showed that oestrone was more abundant than oestradiol-17 beta and oestriol combined, but the relative contribution of individual oestrogens to the total oestrogen complement differed. In the sample from the capuchin, an immunoreactive oestrogen slightly less polar than oestradiol appeared to be the most abundant urinary oestrogen.

Animals↗
PubMed1980

Annual circulating testosterone levels in captive and free-ranging male armadillos (Dasypus novemcincuts).

Mean circulating concentrations and seasonal changes in plasma testosterone over 3 years were similar in free-ranging and captive male armadillos. The highest concentrations were seen in the summer months, i.e. at the time of maximum breeding, but the relatiely high values at other times and the inability of ACTH to restore dexamethasone-suppressed testosterone concentrations confirms that testicular function continues throughout the year. There was a gradual rise in plasma testosterone to adult levels from the 5th to the 9th month of life in captive-born males, indicating that sexual maturity is reached within the first year of life and that captivity is not deleterious to Leydig cell function.

Adrenal Glands↗
PubMed1980

Monitoring the female reproductive cycle of great apes and other primate species by determination of oestrogen and LH in small volumes of urine.

A practical approach for monitoring the reproductive cycle of primates is described. Ovulation, implantation, gestation and post-partum amenorrhoea were identified from measurements of total immunoreactive oestrogen and LH bioactivity in incomplete daily urine samples collected from various species, including a gorilla, a chimpanzee and an orang-utan. Oestrogen values were determined by radioimmunoassay of hydrolysed urine using a non-specific oestriol antiserum and LH was assessed by measuring testosterone output from dispersed rat Leydig cells. Both hormone measurements were indexed by urinary creatinine levels to help adjust for differences in urine concentration and volume.

Animals↗
PubMed1979

Estrogen and luteinizing hormone secretion in diverse primate species from simplified urinary analysis.

A practical approach for monitoring urinary estrogen and luteinizing hormone (LH) in various primate species is described. Total immunoreactive estrogen (Et) levels, measured without chromatography, provided a convenient estimation of estrone, estradiol and estriol as the sum of their separated parts. Bioactive LH in urine was measured by the rat interstitial cell testosterone (RICT) in vitro bioassay. Correction for urinary creatinine content allowed for the comparison of hormone production from small volumes of urine collected from single daily voidings. Using these methods, urinary Et and LH profiles through the reproductive cycles of a human, gorilla, chimpanzee and capuchin monkey have been determined.

Animals↗
PubMed1975

Circulating gonadotropins, estrogens, and androgens in polycystic ovarian disease.

Serum gonadotropin, estrogen, and androgen levels were measured in samples obtained from 19 patients with polycystic ovarian disease (PCO) and from 10 normal women on day 2 to 4 of their menstrual cycles. In patients with PCO, the mean (plus or minus S.E.) concentration was significantly higher (P smaller than 0.001) than the concentrations found in the normal subjects for LH (35 plus or minus 4.6 vs. 12.7 plus or minus 2.6 m.I.U. per milliliter), but not for FSH (10.3 plus or minus 0.7 vs. 8.7 plus or minus 0.9 m.I.U. per milliliter). Estrone (E1) levels (92 plus or minus 4 vs. 52 plus or minus 5 pg. per milliliter) were also significantly higher (P smaller than 0.001), while estradiol (E2) concentrations (58 plus or minus 4 vs. 63 plus or minus 8 pg. per milliliter) were comparable. Testosterone (T) (468 plus or minus 41 vs. 325 plus or minus 34 pg. per milliliter, P smaller than 0.05), androstenedione (delta) (2,083 plus or minus 138 vs. 1,123 plus or minus 153 pg. per milliliter, P smaller than 0.001), and dehydroepiandrosterone sulfate (3.4 plus or minus 0.4 vs. 2.0 plus or minus 0.37 mug per milliliter, P smaller 0.02) were also significantly increased over the values in normal controls. The mean dehydroepiandrosterone (DHEA) was elevated in the patients with PCO (11.3 plus or minus 1.7 vs. 7.5 plus or minus 1.2 mug per milliliter), but was not significantly different. A positive correlation was found between LH levels and both E2 and E1 concentrations in the patients with PCO. These data show a distinct profile of gonadotropin, estrogen, and androgen levels in patients with PCO.

Adolescent↗
PubMed1975

Circulating estradiol, estrone and gonadotropin levels following the administration of orally active 17beta-estradiol in postmenopausal women.

Ingestion of a single tablet containing 2 mg micronized 17beta-estradiol (E-2) produced marked increases in the serum concentrations of E-2 and estrone (E-1) in 9 postmenopausal women. The rise in circulating E-2 became significant within 2 h, reached a maximum (110 pg/ML; 437% increase) at 5 h, and remained significantly elevated at 8 h posttreatment. By 24 h, the serum E-2 concentration was not significantly different than baseline. In contrast, a more rapid (within 1 h) and pronounced (4-fold) increase in the serum concentration of E-1 was observed. This rise continued until a peak (467 pg/ml; 2000%) was reached 6 h posttreatment. Thereafter, the serum E-1 concentration declined progressively but was still significantly elevated (140 pg/ml; P smaller than 0.01) 24 h after treatment. Serum concentrations of FSH AND LH were significantly decreased within 6 and 3 h, respectively and both gonadotropins remained significantly suppressed 24 h following the ingestion of E-2. The ratios of circulating E-1: E-2 reported herein (ca. 3-6) were much higher than those observed by other investigators following iv E-2 (I.E., smaller than 1). Thus the data indicate that micronized E-2 peros is readily absorbed and that during this process a significant portion of the hormone is converted to E-1 by the gstrointestinal tract. In addition, 2 mg oral E-2 exerts significant biologic activity as assessed by serum gonadotropin suppression.

Administration, Oral↗