Distribution, metabolism, and fetal uptake of pentavalent arsenic in pregnant mice following oral or intraperitoneal administration

Pregnant CD-1 mice were treated with 20 (i.p.) or 40 (p.o.) mg/kg sodium arsenate on gestation day 18 (plug = day 1). Individual fetuses, pooled placentas and maternal blood, urine, liver, and kidneys were obtained from three or more litters at intervals up to 24 hours following treatment. Acid-digested samples were analyzed for total arsenic by hydride generation atomic absorption spectrophotometry. The rate of arsenic elimination from maternal samples was not influenced by administration route. First-order elimination followed a brief period of distribution, and the biological half-life was approximately 10 hours. Arsenic was found in most samples, with mean peak concentrations expressed as micrograms As/gm (wet wt.) or /ml (values listed are post-treatment sampling times in minutes or hours and concentrations for i.p. and for p.o. treated groups, respectively) as follows: fetuses-2, 3.5; 6, 0.8, placentas-2, 9.3; 1, 2.3, blood-10 minutes, 6.9; 1, 2.0, urine-1, 712; 2, 342, kidney-20 minutes, 25.4; 1, 11.0, liver-0.5, 7.9; 1, 11.7. By 24 hours, arsenic levels in fetuses and placentas had declined to 0.22 microgram/gm and 0.74 microgram/gm for i.p. and 0.33 microgram/gm and 0.57 microgram/gm for p.o. treatments, respectively. Fetal arsenic uptake and loss were more rapid following i.p. than p.o. treatments, and although the i.p. dose was only half that used p.o., peak fetal As+5 was almost fivefold higher following i.p. treatment. These results agree with the finding that oral dosing of pregnant mice with arsenate has less effect on the conceptus than does treatment by injection.(ABSTRACT TRUNCATED AT 250 WORDS)     

Pharmacokinetics of iloprost and cicaprost in mice.

Iloprost and cicaprost are two PGI2-mimetics, which are chemically stable and highly pharmacologically potent. Both compounds differ by their susceptibility to metabolic degradation. While iloprost contains a pentanoic acid upper side chain, which is subject to beta-oxidative degradation, cicaprost is metabolically stabilized by the introduction of an oxygen atom at position 3 of the pentanoic acid chain, preventing beta-oxidation. Both compounds have been characterized concerning their pharmacological and pharmacokinetic profile in a number of animal species and in man. In the present set of experiments both drugs were characterized in terms of pharmacokinetics in mice, an animal species quite routinely used in long-term toxicity studies on cancerogenicity, by iv and ig administration of 0.2 mg/kg (iloprost) and 0.01 mg/kg (cicaprost) using tritiated substances. Iloprost was rapidly inactivated after iv dosing with plasma levels declining from 247 to 0.27 ng/ml within 60 min. Disposition half-lives were 3 and 14 min. Total clerance accounted for 152 ml/min/kg. Total radiolabel exhibited a clearance of 35 ml/min/kg, its AUC in plasma was 146 ng-equiv.h/ml. After ig administration Iloprost peak plasma levels of 9.2 ng/ml occurred after 5 min. Bioavailability was 10%. AUC of total radiolabel was 152 ng-equiv.h/ml, showing complete absorption. Excretion of 3H-label was 41%/57% of dose (iv) and 36%/47% o.d. (ig) with the urine and 32%/18% o.d. (iv) and 36%/25% o.d. (ig) in male/female animals and proceeded for > 90% of dose fraction recovered with half-lives of 0.2-0.3 d. Metabolic patterns revealed the known profile consisting of unchanged drug, dinor- and tetranor-metabolites in plasma and mainly, tetranor-products in urine and feces. After iv dosing of cicaprost total radiolabel plasma levels declined biphasically with half-lives of approx. 0.05 h and 0.31 h. Extrapolated AUC was 1.6 ng-equiv. h/ml and total clearance accounted for 108 ml/min/kg. After ig treatment peak radioactivity plasma levels of 0.7 and 1 ng-equiv./ml were observed at 0.16 and 1 h postdose, probably due to differences between animal groups. Extrapolated AUC was 1 ng-equiv.h/ml. Excretion of 3H-label was mainly biliary: With the feces 83%/89% o.d. (iv) and 93%/92% o.d. (ig) were excreted by male/female animals, while 8.3%/5.7% o.d. (iv) and 2.6%/5.5% were recovered in the urine. More than 90% of the excreted radiolabel was found in samples collected up to 24 h postdose. Metabolic patterns in plasma revealed that after both routes of administration 3H-cicaprost was the dominant radiolabel fraction accounting for up to 90% of total radiolabel chromatographed.(ABSTRACT TRUNCATED AT 400 WORDS)     

Development of a high-performance liquid chromatographic method to determine the concentration of karenitecin,a novel highly lipophilic camptothecin derivative,in human plasma and urine

Karenitecin is a novel, highly lipophilic camptothecin derivative with potent anticancer potential. We have developed a sensitive high-performance liquid chromatographic method for the determination of karenitecin concentration in human plasma and urine. Karenitecin was isolated from human plasma and urine using solid-phase extraction. Separation was achieved by gradient elution, using a water and acetonitrile mobile phase, on an ODS analytical column. Karenitecin was detected using fluorescence detection at excitation and emission wavelengths of 370 and 490 nm, respectively. Retention time for karenitecin was 16.2±0.5 min and 8.0±0.2 min for camptothecin, the internal standard. The karenitecin peak was baseline resolved, with the nearest peak at 3.1 min distance. Using normal volunteer plasma and urine from multiple individuals, as well as samples from the 50 patients analyzed to date, no interfering peaks were detected. Inter- and intra-day coefficients of variance were <4.4 and 7.1% for plasma and <4.9 and 11.6% for urine. Assay precision, based on an extracted karenitecin standard plasma sample of 2.5 ng/ml, was +4.46% with a mean accuracy of 92.4%. For extracted karenitecin standard urine samples of 2.5 ng/ml assay precision was +2.35% with a mean accuracy of 99.5%. The mean recovery of karenitecin, at plasma concentrations of 1.0 and 50 ng/ml, was 81.9 and 87.8% respectively. In urine, at concentrations of 1.5 and 50 ng/ml, the mean recoveries were 90.3 and 78.4% respectively. The lower limit of detection (LLD) for karenitecin was 0.5 ng/ml in plasma and 1.0 ng/ml in urine. The lower limit of quantification (LLQ) for karenitecin was 1 ng/ml and 1.5 ng/ml for plasma and urine, respectively. Stability studies indicate that when frozen at −70°C, karenitecin is stable in human plasma for up to 3 months and in human urine for up to 1 month. This method is useful for the quantification of karenitecin in plasma and urine samples for clinical pharmacology studies in patients receiving this agent in clinical trials.     

A radio-gas chromatographic method for the determination of 11-oxotestosterone in fish plasma: its use in confirming estimations by radioimmunoassay

A radio-gas chromatographic method has been devised for the estimation of 11-oxotestosterone (17beta-hydroxyandrost-4-ene-3, 11-dione) in fish plasma samples which provides an independent means of validating the radioimmunoassay described earlier. Estimates of the concentration of 11-oxotestosterone in a sample of male rainbow trout plasma by radio-gas chromatography using peak height and peak weight measurements were 6.9 microgram/100 ml and 7.4 microgram/100 ml respectively, in good agreement with that of 7.1 microgram/100 ml determined by radioimmunoassay.     

Determination of amdinocillin in plasma and urine by high-performance liquid chromatography

A rapid, sensitive and specific high-performance liquid chromatographic (HPLC) assay was developed for the determination of amdinocillin (formerly mecillinam) in human plasma and urine. The assay is performed by direct injection of a plasma protein-free supernatant or a dilution of urine. A 10-μm μBondapak phenyl column with an eluting solvent of water—methanol—1 M phosphate buffer, pH 7 (70:30:0.5) was used, with UV detection of the effluent at 220 nm. Azidocillin potassium salt [potassium-6-(d-(-)-α-azidophenyacetamido)-penicillanate] was used as the internal standard and quantitation was based on peak height ratio of amdinocillin to that of the internal standard. The assay has a recovery of 74.4 ± 6.3% (S.D.) in the concentration ranges of 0.1–20 μg per 0.2 ml of plasma with a limit of detection equivalent to 0.5 μg/ml plasma. The urine assay was validated over a concentration range of 0.025–5 mg/ml of urine, and has a limit of detection of 0.025 mg/ml (25 μg/ml) using a 0.1-ml urine specimen per assay.The assay was applied to the determination of plasma and urine concentrations of amdinocillin following intravenous administration of a 10 mg/kg dose of amdinocillin to two human subjects. The HPLC and microbiological assays were shown to correlate well for these samples.     

大熊猫生殖生物学研究:Ⅰ.大熊猫发情期血清和尿液中促黄体素、孕酮和17β-雌二醇含量的变化

作者用放射免疫法和生物测定法对4只大熊猫发情期血清和尿液中的促黄体素、孕酮和17β-雌二醇的含量进行分析。结果表明:3只大熊猫在发情高峰期均出现雌二醇和促黄体素高峰;LH峰值出现在E_2峰值之后。根据雌兽在发情期血清和尿液中这二种激素含量的变化可为选择人工授精的最佳时间提供可靠的理论依据。     

Liquid chromatography-tandem mass spectroscopy assay for quercetin and conjugated quercetin metabolites in human plasma and urine

A sensitive and specific method was developed and validated for the quantitation of quercetin in human plasma and urine. The application of liquid chromatography-tandem mass spectrometry (LC/MS/MS) with a TurboIonspray (TIS) interface in negative mode under multiple reactions monitoring was investigated. Chromatographic separation was achieved on a C12 column using a mobile phase of acetonitrile/water with 0.2% formic acid (pH 2.4) (40/60, v/v). The detection limit was 100 pg/ml and the lower limit of quantification was 500 pg/ml for plasma samples; the detection limit was 500 pg/ml and the lower limit of quantification was 1 ng/ml for urine samples. The calibration curve was linear from 1 to 800 ng/ml for plasma samples and was linear from 1 to 200 and 50 to 2000 ng/ml for urine samples. All the intra- and inter-day coefficients of variation were less than 11% and intra- and inter-day accuracies were within +/-15% of the known concentrations. This represents a LC/MS/MS assay with the sensitivity and specificity necessary to determine quercetin in human plasma and urine. This assay was used to determine both parent quercetin and the quercetin after enzymatic hydrolysis with beta-glucuronidase/sulfatase in human plasma and urine samples following the ingestion of quercetin 500 mg capsules.     

Volume expansion during NOS substrate donation with L-arginine: regulatory offsetting of renal response?

The responses to infusion of nitric oxide synthase substrate (L-arginine 3 mg.kg(-1).min(-1)) and to slow volume expansion (saline 35 ml/kg for 90 min) alone and in combination were investigated in separate experiments. L-Arginine left blood pressure and plasma ANG II unaffected but decreased heart rate (6 +/- 2 beats/min) and urine osmolality, increased glomerular filtration rate (GFR) transiently, and caused sustained increases in sodium excretion (fourfold) and urine flow (0.2 +/- 0.0 to 0.7 +/- 0.1 ml/min). Volume expansion increased arterial blood pressure (102 +/- 3 to 114 +/- 3 mmHg), elevated GFR persistently by 24%, and enhanced sodium excretion to a peak of 251 +/- 31 micromol/min, together with marked increases in urine flow, osmolar and free water clearances, whereas plasma ANG II decreased (8.1 +/- 1.7 to 1.6 +/- 0.3 pg/ml). Combined volume expansion and L-arginine infusion tended to increase arterial blood pressure and increased GFR by 31%, whereas peak sodium excretion was enhanced to 335 +/- 23 micromol/min at plasma ANG II levels of 3.0 +/- 1.1 pg/ml; urine flow and osmolar clearance were increased at constant free water clearance. In conclusion, L-arginine 1) increases sodium excretion, 2) decreases basal urine osmolality, 3) exaggerates the natriuretic response to volume expansion by an average of 50% without persistent changes in GFR, and 4) abolishes the increase in free water clearance normally occurring during volume expansion. Thus L-arginine is a natriuretic substance compatible with a role of nitric oxide in sodium homeostasis, possibly by offsetting/shifting the renal response to sodium excess.     

beta-hydroxy-beta-methylbutyrate (HMB) kinetics and the influence of glucose ingestion in humans

The dietary supplement, beta-hydroxy-beta-methylbutyrate (HMB), has been shown to decrease muscle proteolysis during the stress of exercise and disease. The aim of this investigation was to determine the time course kinetics of HMB and to determine whether oral glucose ingestion alters the kinetics. In Study 1, eight males (32 +/- 10 yrs) participated in two randomize trials: 1) oral ingestion of 1g of HMB with water in capsule form (HMB), and 2) placebo. Blood samples were obtained prior to ingestion of treatment and at 30, 60, 90, 120, 150, and 180 min for the measurement of plasma HMB. Additional blood samples were obtained at 6, 9, and 12 hr. Urine was collected prior to ingestion and at 3, 6, 9, and 12 h for the measurement of urinary HMB. In Study 2, eight males (25 +/- 6 yrs) followed the same study design and testing procedure as for Study 1. Treatments were 1) modified glucose tolerance test (75 g glucose) (GLU), 2) oral ingestion of 3 g of HMB with water (HMB), and 3) ingestion of 3 g of HMB with 75 g of glucose (HMB+GLU). Blood samples were analyzed for insulin, glucose, and HMB. Additional blood samples were obtained at 24h and 36h for the measurement of HMB. Additional urine samples were collected at 24h and 36h. In Study 1, plasma HMB peaked at 120 nmol/ml at 2.0 +/- 0.4 hr in HMB trial. Half-life was 2.37 +/- 0.1 hr. Following the consumption of 1g of HMB, approximately 14% of the HMB consumed accumulated in the urine. In Study 2, plasma glucose and insulin levels were significantly greater in GLU and HMB+GLU treated subjects compared to HMB treated subject at minutes 30, 60 and 90. Plasma HMB peaked at 487.9 +/- 19.0 nmol/ml at 1.0 +/- 0.1 hr in the HMB treated subjects and at 352.1 +/- 15.3 nmol/ml at 1.94 +/- 0.2 hr when subjects consumed HMB+GLU. The time to reach peak was different (P <0.001) between HMB and HMB+GLU. The plasma HMB half-life was less (P = 0.08) 2.38 +/- 0.1 hr in HMB trial compared to 2.69 +/- 0.2 hr in HMB+GLU trial. Area under the plasma HMB curve during the first 3 hr was less (P = 0.002) in the HMB+GLU trial compared to the HMB trial. From 3 h through 36 h the area under the HMB curve tended to be less (P = 0.106) for the HMB+GLU compared to the HMB alone. HMB accumulation in the urine as well as the area under the curve were similar with both HMB (94875.8 +/- 15159.5 nmol/36 hrs) and HMB+GLU (80678.2 +/- 3863.1 nmol/36 hrs). The percentage of the HMB dose that accumulates in the urine was 27% for HMB+GLU and 29% for HMB alone. In conclusion, HMB plasma levels peak within 60 to 120 min depending on the amount of HMB consumed and whether glucose is consumed with HMB. The plasma half-life is approximately 2.5 hr. Plasma HMB reaches baseline levels at approximately 9 hr following ingestion. However, 70 to 85% of the ingested oral HMB is retained in the body for further metabolism.     

Gentamicin: use of a programmable calculator to determine dosages from pharmacokinetic data for individual patients.

Gentamicin, an antibiotic frequently used in the treatment of gram-negative infections, has a narrow therapeutic index, so the correct prediction of its serum concentrations is important. Recent studies have emphasized the dubious accuracy of commonly used formulas, and computer programs that provide pharmacokinetic data for individual patients from multiple blood samples have helped to adjust dosages but are expensive. This study tested the applicability of a method using only two blood samples and a programmable calculator to estimate pharmacokinetic parameters for individual patients and adjust dosages to aim at peak and trough serum levels of 6 and 1 micrograms/ml respectively. In the 48 patients with normal renal function this method produced peak serum concentrations of gentamicin within 1 microgram/ml of the desired level in 22 (46%) and therapeutic peak concentrations (between 4 and 10 micrograms/ml) in all the patients. In 10 patients with renal failure it produced peak serum concentrations within 1 microgram/ml of the desired value in 4 and therapeutic serum concentrations in 7. Two patients had peak concentrations below 4 micrograms/ml and one had a peak concentration above 10 micrograms/ml. Two of the three patients whose serum levels were outside the therapeutic range had unstable renal insufficiency. Thus, patients with renal insufficiency need continued monitoring of the serum level of gentamicin, particularly when their renal function is changing.     

Determination of alpha-naphthylisothiocyanate and metabolites alpha-naphthylamine and alpha-naphthylisocyanate in rat plasma and urine by high-performance liquid chromatography

A rapid and sensitive high-performance liquid chromatographic (HPLC) assay for the determination of alpha-naphthylisothiocyanate (1-NITC) and two metabolites alpha-naphthylamine (1-NA) and alpha-naphthylisocyanate (1-NIC) in rat plasma and urine has been developed. The chromatographic analysis was carried out using reversed-phase isocratic elution with a Partisphere C(18) 5-microm column, a mobile phase of acetonitrile-water (ACN-H(2)O 70:30, v/v), and detection by ultraviolet (UV) absorption at 305 nm. The lower limits of quantitation (LLQ) in rat plasma, urine, and ACN were 10, 30, and 10 ng/ml for 1-NITC; 30, 100, and 30 ng/ml for 1-NA; and 30 ng/ml in ACN for 1-NIC. At low (10 ng/ml), medium (500 ng/ml), and high (5000 ng/ml) concentrations of quality control samples (QCs), the range of within-day and between-day accuracies were 95-106 and 97-103% for 1-NITC in plasma, respectively. Stability studies showed that 1-NITC was stable at all tested temperatures in ACN, and at -20 and -80 degrees C in plasma, urine, and ACN precipitated plasma and urine, but degraded at room temperature and 4 degrees C. 1-NA was stable in all of the tested matrices at all temperatures. 1-NIC was unstable in plasma, urine, and ACN precipitated plasma and urine, but stable in ACN. The degradation product of 1-NITC and 1-NIC in universal buffer was confirmed to be 1-NA. 1-NITC and 1-NA were detected and quantified in rat plasma and urine, following the administration of a 25 mg/kg i.v. dose of 1-NITC to a female Sprague-Dawley rat.     

Circadian and circannual rhythms of melatonin in plasma of male white-tailed deer and the effect of oral administration of melatonin

Circadian levels of melatonin (M) were determined in plasma of four male white-tailed deer sampled hourly in September for 24 h via indwelling jugular catheter. Concentrations of M, detected by the radioimmunoassay rise with the onset of darkness, peak at 1.00 h (265 pg/ml) and then quickly decline to baseline levels (60 to 70 pg/ml) maintained during the scotophase. Orally administered M (5 mg, given at 13:00 h) induced a rapid elevation of plasma M (peak 980 pg/ml at 15:00 h) followed by a decline to baseline (100 pg/ml) reached at 22:00 h. The usual midscotophase peak was abolished by exogenous M administration. Seasonal midscotophase levels of M (determined in three samples taken 45 min apart between 23:00 and 1:00 h reach maximum in December (1530 pg/ml) followed by decline to minimum (69 to 90 pg/ml) observed between May and July. The data indicate that: 1) similarly to other mammals, deer exhibit peak levels of M during the dark phase; 2) 5 mg of M given orally caused a rapid elevation of M levels in blood followed by a depression of the normally present night-time peak; and 3) midscotophase levels of M exhibit very pronounced seasonal fluctuations which might be related to yearly cycles, such as the reproduction, hair molt, and antler growth.     

Competitive protein-binding radioassay of corticosterone in the plasma of the frog, Rana esculenta L. (author's transl)]

1. Plasma corticosterone levels were measured in the plasma of the edible frog, Rana esculenta, by a competitive protein-binding radioassay method using baboon plasma as CBG source. 2. This technique was sensitive enough to make the assessment of corticosterone levels in 50 microliter plasma samples possible. The assay sensitivity threshold reached 0.5 ng per tube and the corticosterone rate assessment was correct between 0 and 5 ng. The specificity was tested, using 12 different steroids (fig. 2) : baboon CBG had very slight avidity for aldosterone, the second circulating steroid in frog plasma. 3. Using this technique, we have shown that plasma corticosterone underwent seasonal variations. Plasma corticosterone levels, in animals captured in nature during February and June, were 1.51 +/- 0.06 microgram/100 ml (n = 60) and 2.76 +/- 0.14 microgram/100 ml (n = 36), respectively, as appeared in table III. 4. It appeared that the interrenal gland of the frog was not totally dependent on pituitary ACTH, since total hypophysectomy reduced, but did not suppress, corticosterone secretion (table III).     

Gas chromatographic determination of novel valproyl taurinamide derivatives in mouse and dog plasma

Valproyl taurinamides are a novel group of compounds that possess anticonvulsant activity. In this study a gas chromatographic micromethod was developed for the quantification of selected valproyl taurinamides and some of their metabolites in biological samples. Valproyl taurinamide (VTD), N-methyl valproyl taurinamide (M-VTD), N,N-dimethyl valproyl taurinamide (DM-VTD) and N-isopropyl valproyl taurinamide (I-VTD) were analyzed in mouse and dog plasma and in dog urine using gas chromatography. Flame ionization detection and mass spectrometric detection were compared. The plasma samples were prepared by solid-phase extraction using C(18) cartridges. The urine samples were prepared by liquid-liquid extraction. The sample volume used was 100 microl of dog plasma, 50 microl of mouse plasma and 20 microl of dog or mouse urine. The quantification range of the method was 1.5-50 mg/l in dog plasma (VTD only), 2.5-250 mg/l in mouse plasma (0.7-90 pmol injected) and 0.04-2 mg/ml in dog urine (VTD only). The inter-day precision in plasma and urine samples was around 10% for all quantified concentrations except LOQ (15-20%). The accuracy for all four compounds was between 90 and 110% within the entire concentration range. The developed method was suitable for quantification of a series of CNS-active valproyl taurineamide derivatives in biological samples at relevant in vivo concentrations.     

Determination of myo-inositol in biological samples by liquid chromatography-mass spectrometry

A high-performance liquid chromatographic method using liquid-liquid extraction was developed for the determination of 1-(3-fluoro-4-hydroxy-5-mercaptomethyl-tetrahydrofuran-2-yl)-5-methyl-1H-pyrimidine-2,4-dione (l-FMAUS; I) in rat plasma and urine. A 100 microl aliquot of distilled water containing l-cysteine (100 mg/ml) was added to a 100 microl aliquot of biological sample. l-Cysteine was employed to protect binding between the 5'-thiol of I and protein in the biological sample. After vortex-mixing for 30s and adding a 50 microl aliquot of the mobile phase containing the internal standard (10 microg/ml of 3-aminophenyl sulfone), 1 ml of ethyl acetate was used for extraction. After vortex-mixing, centrifugation, and evaporating the ethyl acetate, the residue was reconstituted with a 100 microl aliquot of the mobile phase. A 50 microl aliquot was injected onto a C(18) reversed-phase column. The mobile phases, 50 mM KH(2)PO(4) (pH = 2.5):acetonitrile (85:15, v/v) for rat plasma and 50 mM KH(2)PO(4) (pH 2.5):acetonitrile:methanol (85:10:5, v/v/v) for urine samples, were run at a flow-rate of 1.2 ml/min. The column effluent was monitored by an ultraviolet detector set at 265 nm. The retention times for I and the internal standard were approximately 9.7 and 12.5 min, respectively, in plasma samples and the corresponding values in urine samples were 16.8 and 14.9 min. The quantitation limits of I in rat plasma and urine were 0.1 and 0.5 microg/ml, respectively.     

Social suppression of ovarian cyclicity in captive and wild colonies of naked mole-rats, Heterocephalus glaber

To investigate the endocrine cause of reproductive suppression in nonbreeding female naked mole-rats, animals from 35 colonies were studied in captivity. Urinary and plasma progesterone concentrations were elevated in pregnant females (urine: 10.0-148.4 ng/mg Cr, 27 samples from 8 females; plasma: 3.6-30.0 ng/ml, 5 samples from 5 females; Days 21-40 of pregnancy) and cyclic breeding females (urine: 0.5-97.8 ng/mg Cr, 146 samples from 7 females; plasma: less than 1.0-35.4 ng/ml, 25 samples from 7 females). The latter group showed cyclic patterns of urinary progesterone, indicating a mean ovarian cycle length of 34.4 +/- 1.6 days (mean +/- s.e.m.) with a follicular phase of 6.0 +/- 0.6 days and a luteal phase of 27.5 +/- 1.3 days (19 cycles from 9 breeding females). In non-breeding females urinary and plasma progesterone values were undetectable (urine: less than 0.5 ng/mg Cr, 232 samples from 64 females; plasma: less than 1.0 ng/ml, 7 samples from 6 females). Breeding females had higher (P less than 0.001) plasma LH concentrations (3.0 +/- 0.2 mi.u./ml, 73 samples from 24 females) than did non-breeding females (1.6 +/- 0.1 mi.u./ml, 57 samples from 44 females). Urinary and plasma progesterone concentrations in non-breeding females from wild colonies situated near Mtito Andei, Kenya, were either below the assay sensitivity limit (urine: less than 0.5 ng/mg Cr, 11 females from 2 colonies; plasma: less than 1.0 ng/ml, 25 females from 4 colonies), or very low (plasma: 1.6 +/- 0.6 ng/ml, 15 females from 4 colonies). In captivity, non-breeding females removed from their colonies (i.e. the dominant breeding female) and either paired directly with a non-breeding male (N = 2), or removed and housed singly for 6 weeks before pairing with a non-breeding male (N = 5) may develop a perforate vagina for the first time in as little as 7 days. Urinary progesterone concentrations rose above 2.0 ng/mg Cr (indicative of a luteal phase) for the first time 8.0 +/- 1.9 days after being separated. These results suggest that ovulation is suppressed in subordinate non-breeding female naked mole-rats in captive and wild colonies, and show that plasma LH concentrations are significantly lower in these non-breeding females. This reproductive block in non-breeding females is readily reversible if the social factors suppressing reproduction are removed.     

Liquid chromatography-tandem mass spectrometry analysis of oleuropein and its metabolite hydroxytyrosol in rat plasma and urine after oral administration

We describe a liquid chromatography-electrospray ionisation tandem mass spectrometry method for the qualitative and quantitative determination of the secoiridoid oleuropein and its bioactive metabolite hydroxytyrosol in rat plasma and urine. Samples were prepared by liquid-liquid extraction using ethyl acetate with a recovery for both compounds of about 100% in plasma and about 60% in urine. The chromatographic separation was performed with a RP-ODS column using a water-acetonitrile linear gradient. The calibration curve was linear for both biophenols over the range 2.5-1000 ng/ml (LOD 1.25 ng/ml) for plasma and 5-1000 ng/ml (LOD 2.5 ng/ml) for urine. Plasma concentrations of oleuropein and hydroxytyrosol were measured after oral administration of a single dose (100 mg/kg) of oleuropein. Analysis of treated rat plasma showed the presence of unmodified oleuropein, reaching a peak value of 200 ng/ml within 2 h, with a small amount of hydroxytyrosol, whereas in urine, both compounds were mainly found as glucuronides.     

Effect of in vivo prostaglandin treatment on 3H-PGF2alpha uptake in hamster corpora lutea.

Pregnant hamsters were administered (SC) prostaglandin or vehicle on the morning of the 4th day of pregnancy. Serum progesterone was significantly depressed (p less than .01) at 0.5, 2, and 6 hours after treatment with 100 microgram PGF2alpha. Serum progesterone levels were unchanged 2 hours and 6 hours after treatment with 100 microgram PGF2beta and 2 hours after treatment with 1 mg PGF2beta. Progesterone levels were depressed to less than 1 ng/ml 6 hours after treatment with 1 mg PGF2beta. The specific uptake of 3H-PGF2alpha in whole hamster corpora lutea was significantly depressed 2 hours and 6 hours following 100 microgram PGF2alpha treatment. A 15% depression in specific uptake occurred 0.5 hour post-treatment. Treatment with 100 microgram PGF2beta resulted in no change. Administration of 1 mg PGF2beta resulted in depressed 3H-PGF2alpha uptake at both 2 and 6 hours post-treatment. Prostacyclin (PGI2) treatment resulted in no change in either 3H-PGF2alpha specific uptake or serum progesterone 2 hours after 100 microgram treatment SC. These parameters were both reduced approximately 30% 6 hours post-treatment. Treatment with 6-keto-PGF1alpha resulted in a complete lack of measurable 3H-PGF2alpha uptake and serum progesterone levels less than 1 ng/ml at both 2 and 6 hours after treatment with 1 mg SC.     

Detection and pharmacokinetics of alginate oligosaccharides in mouse plasma and urine after oral administration by a liquid chromatography/tandem mass spectrometry (LC-MS/MS) method

A sensitive and simple liquid chromatography/tandem mass spectrometry (LC-MS/MS) method was developed for the detection of alginate oligosaccharides (AOs) in mouse plasma and urine after oral administration. In an AO mixture, dimer, trimer, and tetramer were detected by LC-MS/MS equipped with an anion-exchange column with extremely high sensitivity. By this method, we detected certain levels of AOs in samples prepared from mouse plasma and urine after a single oral administration of the AO mixture. Based on a calibration curve made with an AO trimer peak area as a standard, the maximum plasma and urine concentrations of AOs were estimated to be 24.5 microg/ml at 5 min and 425.5 microg/ml at 30 min, respectively. These results suggest that the LC-MS/MS method is well suited to pharmacokinetic analysis of AOs in an in vivo system, and that some of orally administered AOs, at least from dimer to tetramer, are absorbed by digestive organs promptly, and that unaltered, these oligomers were excreted into an urine after a single oral administration to a mouse.     

Anomalies in mineralization of low concentrations of organic compounds in lake water and sewage

The rates of mineralization of nitrilotriacetic acid (NTA), 2,4-dichlorophenoxyacetic acid (2,4-D), p-nitrophenol, aniline, and isopropyl N-phenylcarbamate (IPC) at one or more concentrations ranging from 100 pg/ml to 1.0 microgram/ml were proportional to chemical concentrations in samples of three lakes. The rates at 100 pg of NTA, 2,4-D, p-nitrophenol, and aniline per ml in samples of one or more lakes were less than predicted, assuming the rates were linearly related to the concentration. Neither NTA nor 2,4-dichlorophenol at 2.0 ng/ml was mineralized in some lake waters, but higher levels of the two chemicals were converted to CO2 in samples of the same waters. In samples from two lakes, little or no mineralization of IPC or 2,4-D occurred at 1.0 microgram/ml, but 10 ng/ml or lower levels of the herbicides were mineralized. The mineralization in sewage of 1.0 microgram of NTA per ml was biphasic; about 20% of the substrate was mineralized in 20 h, and mineralization was only reinitiated after a period of 130 h. The biphasic transformation was not a result of the accumulation of organic products, and it was still evident if protozoan activity was inhibited. NTA also underwent a biphasic mineralization in lake waters, and the biphasic pattern was not altered by additions of growth factors and inorganic nutrients. From 40 to 60% of the carbon of aniline added to lake water at levels of 100 pg/ml to 1.0 microgram/ml was mineralized, but more than 90% of the carbon of NTA, 2,4-D, or p-nitrophenol added to lake water at 10 ng/ml or 1.0 microgram/ml was mineralized.(ABSTRACT TRUNCATED AT 250 WORDS)