scholarly journals 5α-dihydroprogesterone concentrations and synthesis in non-pregnant mares

2018 ◽  
Vol 238 (1) ◽  
pp. 25-32 ◽  
Author(s):  
A J Conley ◽  
E L Scholtz ◽  
E L Legacki ◽  
C J Corbin ◽  
H K Knych ◽  
...  
Keyword(s):  
Hepatic Microsome ◽  
Pregnant Uterus ◽  
Chromatography Tandem Mass Spectrometry ◽  
Hepatic Microsomes ◽  
Before And After ◽  
Liquid Chromatography Tandem Mass ◽  
Highly Correlated ◽  
Progesterone Metabolite

In vivo and in vitro evidence indicates that the bioactive, 5α-reduced progesterone metabolite, 5α-dihydroprogesterone (DHP) is synthesized in the placenta, supporting equine pregnancy, but its appearance in early pregnancy argues for other sites of synthesis also. It remains unknown if DHP circulates at relevant concentrations in cyclic mares and, if so, does synthesis involve the non-pregnant uterus? Jugular blood was drawn daily from cyclic mares (n = 5). Additionally, ovariectomized mares (OVX) and geldings were administered progesterone (300 mg) intramuscularly. Blood was drawn before and after treatment. Incubations of whole equine blood and hepatic microsomes with progesterone were also investigated for evidence of DHP synthesis. Sample analysis for progesterone, DHP and other steroids employed validated liquid chromatography–tandem mass spectrometry methods. Progesterone and DHP appeared a day (d) after ovulation in cyclic mares, was increased significantly by d3, peaking from d5 to 10 and decreased from d13 to 17. DHP was 55.5 ± 3.2% of progesterone concentrations throughout the cycle and was highly correlated with it. DHP was detected immediately after progesterone administration to OVX mares and geldings, maintaining a relatively constant ratio with progesterone (47.2 ± 2.9 and 51.2 ± 2.7%, respectively). DHP was barely detectable in whole blood and hepatic microsome incubations. We conclude that DHP is a physiologically relevant progestogen in cyclic, non-pregnant mares, likely stimulating the uterus, and that it is synthesized peripherally from luteal progesterone but not in the liver or blood. The presence of DHP in pregnant perissodactyla as well as proboscidean species suggests horses may be a valuable model for reproductive endocrinology in other exotic taxa.

scholarly journals Bile Acids Quantification by Liquid Chromatography–Tandem Mass Spectrometry: Method Validation, Reference Range, and Interference Study

Diagnostics ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 462 ◽  
Author(s):  
Elisa Danese ◽  
Davide Negrini ◽  
Mairi Pucci ◽  
Simone De Nitto ◽  
Davide Ambrogi ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Healthy Subjects ◽  
Reference Range ◽  
Tandem Mass ◽  
Chromatography Tandem Mass Spectrometry ◽  
Liquid Chromatography Tandem Mass ◽  
Interference Study

Bile acids (BA) play a pivotal role in cholesterol metabolism. Their blood concentration has also been proposed as new prognostic and diagnostic indicator of hepatobiliary, intestinal, and cardiovascular disease. Liquid chromatography tandem mass spectrometry (LC–MS/MS) currently represents the gold standard for analysis of BA profile in biological samples. We report here development and validation of a LC–MS/MS technique for simultaneously quantifying 15 BA species in serum samples. We also established a reference range for adult healthy subjects (n = 130) and performed a preliminary evaluation of in vitro and in vivo interference. The method displayed good linearity, with high regression coefficients (>0.99) over a range of 5 ng/mL (lower limit of quantification, LLOQ) and 5000 ng/mL for all analytes tested. The accuracies were between 85–115%. Both intra- and inter-assay imprecision was <10%. The recoveries ranged between 92–110%. Each of the tested BA species (assessed on three concentrations) were stable for 15 days at room temperature, 4 °C, and −20 °C. The in vitro study did not reveal any interference from triglycerides, bilirubin, or cell-free hemoglobin. The in vivo interference study showed that pools obtained from hyper-cholesterolemic patients and hyper-bilirubinemic patients due to post-hepatic jaundice for benign cholestasis, cholangiocarcinoma and pancreatic head tumors had clearly distinct patterns of BA concentrations compared with a pool obtained from samples of healthy subjects. In conclusion, this study proposes a new suitable candidate method for identification and quantitation of BA in biological samples and provides new insight into a number of variables that should be taken into account when investigating pathophysiological changes of BA in human diseases.

ZUR FRAGE DER BIOSYNTHESE VON ALDOSTERON UND 11-DESOXYCORTICOSTERON IN DER NEBENNIERE UND IM ADENOM BEI EINEM PATIENTEN MIT PRIMÄREM ALDOSTERONISMUS

1969 ◽  
Vol 62 (3) ◽  
pp. 425-437 ◽  
Author(s):  
K. Dahm ◽  
H. Breuer ◽  
J. M. Bayer
Keyword(s):  
Urinary Excretion ◽  
Normal Values ◽  
Normal Range ◽  
Adrenal Tissue ◽  
Before And After ◽  
Normal Adrenal Tissue ◽  
Progesterone Metabolite ◽  
Very High

ABSTRACT In a 19-year old male patient, suffering from primary aldosteronism, the biosynthesis of 11-deoxycorticosterone and aldosterone was studied in slices of normal and adenomatous adrenal tissue; [4-14C] progesterone and [4-14C] 17α-hydroxyprogesterone were used as substrates. In addition, the urinary excretion of 1 1-deoxycorticosterone, tetrahydro-11-deoxycorticosterone and aldosterone was determined before and after operation. As compared with normal adrenal tissue, a very high activity of the 21-hydroxylase towards progesterone (metabolite: 11-deoxycorticosterone) as well as 17α-hydroxyprogesterone (metabolite: 17α-hydroxy-11-deoxycorticosterone) was found in the adenoma. In contrast, the activity of the 11β-hydroxylase was much less in the adenoma than in the normal adrenal tissue. In the absence of cofactors, only traces of aldosterone were detected in the experiments with slices of the adenoma, whereas a normal rate of production was observed in the experiments with the adrenal slices. The excretion of aldosterone in urine varied between 29.4 and 70.7 μg/24 h before operation; it was unaffected by dietetic measures, thus indicating an autonomy of the tumour. After operation, the concentration of aldosterone in urine fell to normal values (6.1–9.1 μg/24 h). The excretion of free 11-deoxycorticosterone (0.2–2.0 μg/24 h) and of its tetrahydroderivative (31.7–40.4 μg/24 h) was in the normal range before as well as after operation. The increased formation of 11-deoxycorticosterone and the decreased formation of aldosterone in the adenoma under in vitro conditions stand in contrast to the normal excretion of 11-deoxycorticosterone and the increased excretion of aldosterone in urine before operation. This discrepancy may be explained by the deficiency of cofactors in the slices of the adenoma. The results obtained support the view that, in steroid producing organs with high activities, only limited conclusions can be drawn from in vitro experiments to the situation in vivo.

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