Investigations into the Course of Progesterone‐, Oestrogen‐ and eCG‐concentrations During Normal and Impaired Pregnancy in the Mare*

Hoffmann, Bernd; Gentz, F.; Failing, Klaus

doi:10.1111/j.1439-0531.1996.tb01444.x

Cited by 42 publications

(63 citation statements)

References 21 publications

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“…For instance, the increase in 17OH-progesterone and androstenedione, together with progesterone, coincided with the expected stimulation of the primary CL and induction of accessory luteal structures by eCG from the endometrial cups (Allen 1969, Squires et al 1974a. Previous studies have found strong positive correlations between progesterone and eCG concentrations between weeks 5 and 20 of gestation in mares (Squires, et al 1979, Hoffmann et al 1996. The decline in progesterone after week 12 corresponded with the period during which endometrial cups regress and eCG concentrations decline (Allen 1969, Squires et al 1979.…”

Section: Discussionmentioning

confidence: 60%

“…A variety of techniques have been used to measure steroid concentrations in the pregnant mare (Short 1959, van Niekerk et al 1973, Smith 1974, Squires et al 1974a, Burns & Fleeger 1975, Ganjam et al 1975, Holtan et al 1975a, Seren et al 1981, Tsumagari et al 1991, Hoffmann et al 1996. Some investigators utilized assays validated in part by incorporating chromatography in sample preparation (van Niekerk et al 1973, Barnes et al 1975, Ganjam et al 1975, Holtan et al 1975a, Atkins et al 1976 to reduce the potential interference from cross-reacting steroids but the resolution of separation was often limited compared with more contemporary chromatographic methods.…”

Section: Introductionmentioning

confidence: 99%

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The dynamic steroid landscape of equine pregnancy mapped by mass spectrometry

Legacki¹,

Scholtz²,

Ball³

et al. 2016

Reproduction

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Liquid chromatography-tandem mass spectrometry (LC-MS/MS) allowed comprehensive analysis of various steroids detectable in plasma throughout equine gestation. Mares (nZ9) were bled serially until they foaled. Certain steroids dominated the profile at different stages of gestation, clearly defining key physiological and developmental transitions. The period (weeks 6-20) coincident with equine chorionic gonadotropic (eCG) stimulation of primary corpora lutea and subsequent formation of secondary luteal structures was defined by increased progesterone, 17OH-progesterone and androstenedione, all D4 steroids. The 5a-reduced metabolite of progesterone, dihydroprogesterone (DHP) paralleled progesterone secretion at less than half the concentration until week 12 of gestation when progesterone began to decline but DHP concentrations continued to increase. DHP exceeded progesterone concentrations by week 16, clearly defining the luteo-placental shift in pregnane synthesis from primarily ovarian to primarily placental. The period corresponding to the growth of fetal gonads was defined by increasing dehydroepiandrosterone and pregnenolone (D5 steroids) concentrations from week 14, peaking at week 34 and declining to term. Metabolites of DHP (including allopregnanolone) dominated the steroid profile in late gestation, some exceeding DHP by weeks 13 or 14 and near term by almost tenfold. Thus D4 steroids dominated during ovarian stimulation by eCG, inversion of the ratio of progesterone: DHP (increasing 5a-pregnanes) marked the luteo-placental shift, D5 steroids defined fetal gonadal growth and 5a-reduced metabolites of DHP dominated the steroid profile in mid-to late-gestation. Comprehensive LC-MS/MS steroid analysis provides opportunities to better monitor the physiology and the progress of equine pregnancies, including fetal development.

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Section: Discussionmentioning

confidence: 60%

Section: Introductionmentioning

confidence: 99%

The dynamic steroid landscape of equine pregnancy mapped by mass spectrometry

Legacki¹,

Scholtz²,

Ball³

et al. 2016

Reproduction

View full text Add to dashboard Cite

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“…To ensure redissolution of the extracted estrogens in an aqueous medium after evaporation of the organic solvent, 80 ml 0.1 M NaOH with 0.1% BSA were added to the glass vials with the dried extracts, which were then allowed to stand for 10 min at 37 8C. By adding 10 ml M HCl and 0.12 ml concentrated phosphate buffer (2.686 g KH 2 PO 4 ; 8.356 g Na 2 HPO 4 ; and 0.325 g NaN 3 ad 200 ml H 2 O), neutralization and an adjustment to RIA conditions were achieved (Hoffmann et al 1996). The mean interassay coefficient of variation (CV) was 12.4% at a relative binding (B/B 0 ) of 50%.…”

Section: Sample Collection From Hcg-stimulated Boarsmentioning

confidence: 99%

Free and sulfated steroids secretion in postpubertal boars (Sus scrofa domestica)

et al. 2014

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Sulfated steroids have been traditionally regarded as inactive metabolites. However, they may also serve as precursors for the production of active free steroids in target cells. In this study, we used the boar as a model to study the metabolism, transport, and function of steroid sulfates due to their high production in the porcine testicular-epididymal compartment, of which the role is unknown. To characterize the secretion of free and sulfated steroids, plasma samples were collected from six postpubertal boars over 6 h every 20 min from the jugular vein. Long-term secretion profiles were also established in seven boars stimulated with human chorionic gonadotropin. To directly characterize the testicular output, samples were collected from superficial testicular arterial and venous blood vessels. Testosterone, androstenedione and sulfated pregnenolone, DHEA, estrone (E 1 ), and estradiol-17b (E 2 ) were determined by liquid chromatography-tandem mass spectrometry. Free E 1 and E 2 were measured by RIA. Irrespective of a high variability between individuals, the results suggest that i) all steroids assessed are primarily produced in the testis, ii) they exhibit similar profiles pointing to a pulsatile secretion with low frequency (three to five pulses per day), and iii) after synthesis at least a major proportion is immediately released into peripheral circulation. The fact that all steroid sulfates assessed are original testicular products and their high correlations with one another suggest their role as being intermediates of testicular steroidogenesis rather than as being inactivated end products. Moreover, a substantial use of sulfated steroids in porcine testicular steroidogenesis would assign a crucial regulatory role to steroid sulfatase, which is highly expressed in Leydig cells.

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“…The antiserum against oestrone (a gift of Prof. Hoffmann) was previously described (Hoffmann et al 1996). Intra-asay and inter-asay coefficients of variation of the assay for estrone were 8.2% and 15.8%, respectively.…”

Section: Methodsmentioning

confidence: 99%

Concentrations of oestrogens in blood plasma and seminal plasma of boars during the postpuberal period

Zduńczyk¹,

Janowski²,

Raś³

et al. 2011

Polish Journal of Veterinary Sciences

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Concentrations of oestrogens in the blood plasma and seminal plasma of mature boars are high. However, little is known about their concentrations after reaching sexual maturity. The aim of this study was to determine the concentration of oestrogens in blood plasma and seminal plasma of boars during the postpuberal period. Free and conjugated oestrone and oestradiol-17β were determined by radioimmunoassay in blood from the testicular vein and artery, and peripheral circulation as well as in seminal plasma collected from 18 Polish Landrace boars. The animals were divided into three groups (n = 6) according to age (8, 12 and 16 months, respectively). Oestrone was predominant free and conjugated oestrogen. The highest values of oestrogens were measured in the testicular vein (p ≤ 0.05). The concentrations of oestrogens in seminal plasma did not differ from those found in the peripheral circulation. An age-dependent increase in levels of all four oestrogens (p ≤ 0.05) was observed. This can be associated with biochemical maturation of the reproductive system during the postpuberal period.

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Investigations into the Course of Progesterone‐, Oestrogen‐ and eCG‐concentrations During Normal and Impaired Pregnancy in the Mare*

Cited by 42 publications

References 21 publications

The dynamic steroid landscape of equine pregnancy mapped by mass spectrometry

The dynamic steroid landscape of equine pregnancy mapped by mass spectrometry

Free and sulfated steroids secretion in postpubertal boars (Sus scrofa domestica)

Concentrations of oestrogens in blood plasma and seminal plasma of boars during the postpuberal period

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