Search results for: RIA CT Progesterone
#27339652 2016/07/05 Save this To Up
Multiplexed steroid profiling of gluco- and mineralocorticoids pathways using a liquid chromatography tandem mass spectrometry method.Serum steroid assays are major tools in the clinical evaluation of adrenal disorders. The main adrenal steroids are routinely measured with immunoassays. However, chromatographic methods are known to offer better specificity. We report a liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay for simultaneous quantification of 15 adrenal steroids targeting the mineralo- and gluco-corticosteroid pathways. Serum steroids combined with deuterated internal standards were extracted using successive protein precipitation and solid phase extraction steps. Cortisol, cortisone, 11-deoxycortisol, 17-hydroxyprogesterone, 21-deoxycortisol, progesterone, 11-deoxycorticosterone, corticosterone, 11-dehydrocorticosterone, 18-hydroxycorticosterone, 18-hydroxy-11-deoxycorticosterone, aldosterone, dehydroepiandrosterone sulfate, testosterone and androstenedione were resolved in fourteen minutes using a BEH C18 column coupled to a methanol-ammonium formate gradient. Detection was performed using multiple reaction monitoring quantitation. Routinely determined steroid levels by immunoassays were compared to those measured by LC-MS/MS. This method was applied to assess steroid profiles in congenital adrenal hyperplasia (CAH) patients with 21-hydroxylase deficiency. Low quantification limits depending on each steroid (ranging from 0.015ng/mL for aldosterone to 20ng/mL for DHEAS) are adapted to the clinical use. Recoveries of steroids range from 64% for 21-deoxycortisol to 101% for cortisol and are fully corrected by internal standards. A good linearity with R>0.989 is obtained for each compound. The inter-day variation coefficients ranged from 4.7% for cortisol to 16.3% for 11-deoxycorticosterone. The immunoassay for cortisol (Immulite 2000, Siemens) showed acceptable agreement with LC-MS/MS (bias +7.2%). However, Bland-Altman plots revealed large negative bias for aldosterone (-33.4%, AldoCT, CisBio international), for 17-hydroxyprogesterone at concentrations below 2ng/mL (-74.1%, OHP-CT MP Biomedical), for androstenedione (-80.3%, RIA D4, Beckman Coulter) and for 11-deoxycortisol (-125.3%, Diasource Immunoassays). Finally, the analysis of samples from 21-hydroxylase defective patients demonstrated the potential usefulness of multiplexed steroid profiling for the diagnosis and/or monitoring of different forms of congenital adrenal hyperplasia. This LC-MS/MS method provides highly sensitive and specific assessments of mineralo- and glucocorticoids pathways from a small volume sample and is therefore a promising potent tool for clinical and experimental endocrine studies.
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#16999944 2006/11/19 Save this To Up
Low concentrations mono-butyl phthalate stimulates steroidogenesis by facilitating steroidogenic acute regulatory protein expression in mouse Leydig tumor cells (MLTC-1).Di-n-butyl phthalate (DBP) is one of the most dominant phthalate esters and is widely distributed environmental contaminant. Although previous studies have demonstrated that DBP led to a variety of male reproductive abnormalities similar to those caused by androgen receptor antagonists, DBP and its active metabolite, mono-butyl phthalate (MBP), have been demonstrated no affinity for the androgen receptor, but rather exert anti-androgenic effect by altering testosterone biosynthesis. Furthermore, all these results were obtained from very high administrations of DBP or MBP. The purpose of this study was to determine the onset and the site of action of relatively low concentration of MBP on steroidogenesis in vitro. The mouse Leydig tumor cells (MLTC-1) was employed as a cellular model to investigate the effect of MBP on steroidogenesis. Various concentrations of MBP (1, 10, 100 and 1000nmol/l) and its solvent dimethyl sulfoxide (DMSO) were added to the medium for 24h followed by stimulation of some compounds such as human chorionic gonadotrophin (hCG), cholera toxin (CT), forskolin, cAMP analog 8-Br-cAMP, 22(R)-hydroxycholesterol (22R-HC) and pregnenolone. Progesterone in the medium and amounts of intracellular cAMP were measured by RIA. Expression of steroidogenic acute regulatory protein (StAR) was monitored by real-time PCR and Western blotting. The results revealed that the increases of progesterone production in the presence of hCG, CT, forskolin and 8-Br-cAMP were augmented by MBP. In contrast, the levels of intracellular cAMP exhibited no statistical significance when MLTC-1 cells were treated as above. These results implied that the site in the steroid biosynthesis pathway affected by MBP occurs after PKA activation in MLTC-1 cells. Moreover, supplementing the medium with 22R-HC and pregnenolone as progesterone precursors for P450 side chain cleavage enzyme (P450scc) and 3beta-hydroxysteroid dehydrogenase (3beta-HSD), respectively, resulted in no rise in progesterone production, making clear that MBP did not influence the P450scc and 3beta-HSD but on the rate-limiting step, cholesterol transportation into mitochondria. In fact, the above results were confirmed by the upgraded StAR expression in MBP-treated cells. These data support that MBP promotes steroid hormone production by facilitating StAR expression in MLTC-1 cells.
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#15710193 2005/02/15 Save this To Up
Plasma progesterone response following ACTH administration during mid-gestation in the pregnant Brahman heifer.Previous reports of adrenal progesterone (P4) contributions during late gestation in cattle, and ACTH-induced P4 responses in the non-pregnant heifer, prompted a retrospective investigation to evaluate the plasma P4 response and the relative ratio of plasma cortisol (CT) to P4 following ACTH administration during mid-gestation in pregnant Brahman heifers. Twenty-three pregnant (139.0 +/- 5.0 days of gestation) Brahman heifers received one of the following treatments: 0 (saline; n = 5), 0.125 (n = 4), 0.25 (n = 5), 0.5 (n = 4), or 1.0 (n = 5)IU of ACTH per kg BW. Blood samples were collected at -15 and -0.5 (time 0), 15, 30, 45, 60, 75, 105, 135, 165, 195, and 255-min post-ACTH challenge. Plasma P4 and CT were quantified by RIA. Pre-ACTH P4 did not differ (P > 0.10) among ACTH treatment groups (pooled, 12.1 +/- 0.6 ng/mL). Among peak P4 values at 15-min post-ACTH infusion, control P4 (9.6 +/- 1.2 ng/mL) tended to be lower (P < 0.07) than 0.5 IU ACTH-treated heifers (13.3 +/- 1.1 ng/mL); and were lower (P < 0.02) than 0.25 and 1.0 IU ACTH-treated heifers (14.7 +/- 1.1 and 22.2 +/- 3.7 ng/mL, respectively). During the primary P4 response period (0 to 75-min post-ACTH), the area under the curve (AUC) was greater (P < 0.05) for 1.0 IU ACTH-treated heifers than all other groups. The CT:P4 ratios were lower (time x treatment, P < 0.01) for control heifers than all ACTH-treated heifers. Among ACTH-treated heifers, CT:P4 ratio response and CT:P4 ratio AUC were similar (P > 0.10) following ACTH challenge. In conclusion, acute increases in ACTH elevated plasma P4, likely of adrenal origin, in mid-gestation pregnant heifers, while the CT:P4 ratio (relative output) remained constant irrespective of ACTH dose (0.125-1.0 IU). Whether ACTH-induced increases in P4 in pregnant animals are of physiological significance (e.g., an accessory role in the maintenance of pregnancy during periods of acute stress) remains to be determined.
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#9547720 1998/05/15 Save this To Up
[Defects of adrenal steroidogenesis in patients with hirsutism].To determine the frequency and the type of adrenal steroidogenic abnormalities in hirsute women.
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#9304078 1997/09/24 Save this To Up
[Hormone replacement therapy (HRT). The effects at 12 months on the risk factors for menopausal osteoporosis].Cessation of ovarian activity is accompanied by a more or less marked and more or less accelerated reduction in bone mass; the degree and speed of the process--which occurs in all women--depends on individual (genetic factors influencing peak bone mass, duration of child-bearing period), iatrogenic (treatment with corticosteroids or thyroid hormones) or accidental factors (post-traumatic immobilization). Whatever the factor that triggers off the process, the end result is the destruction of bone tissue. This process may be documented by hematochemical (Nordin's test) and instrumental parameters (MOC and similar techniques). Oestroprogestin (and to a lesser extent calcitonin) hormone replacement therapy has been demonstrated to be highly efficacious in countering this involutive process. The authors report data obtained following the evaluation of 35 women in menopause undergoing. Nordin's test and measurement of the plasma level of estradiol using RIA, before and after twelve months after the start of osteoprotective treatment. Of the 35 patients 9 received only progestin, 22 an oestroprogestin combination (of these 18 patients received estrogen transdermally and 4 orally), and 4 calcitonin administered parenterally. A statistically significant positive correlation with Nordin's test was only found in the group receiving oestrogen therapy. In conclusion, it may be affirmed that in the absence of contraindications oestrogens represent the elective form of treatment for menopausal osteoporosis. Acceptable results have been reported in the literature also using calcitonin, but this treatment could not be evaluated in this study owing to the reduced number of the sample treated.
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#8049150 1994/09/06 Save this To Up
Plasma 17-hydroxyprogesterone determination with two commercial immunoassays.Plasma 17-hydroxyprogesterone (17-OH-P) was determined by two commercially available immunoassay kits, a radioimmunoassay (RIA) (OHP-CT, CIS) and an enzyme-immunoassay (EIA) (Serozyme 17 alpha-OH-progesterone, Serono). The determination by RIA was performed according to two procedures, directly on plasma or on a crude plasma extract, whereas that by EIA used only the second procedure. These determinations were carried out in 27 infants below 1 year of age and in 33 women in the follicular phase of the menstrual cycle. The results were compared to those obtained by an in-home RIA (RIA-FRH) which includes an extraction step followed by chromatography on Sephadex LH 20 column. The levels observed were overestimated by both kits. In infants, interference from 17-hydroxy-pregnenolone (17-OH-5P) sulfate occurred when the RIA (CIS) kit was used directly on plasma samples. Using plasma extracts, 17-OH-5P interfered with EIA (Serono) in the infant group and with the RIA (CIS) in the second group. The two kits do not appear to be adequate for 17-OH-P determination at least in infants and in women in the follicular phase of the menstrual cycle.
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