Urinary Oestrogens in the Stallion

Pigon, H.; Lunaas, T.; Velie, Weiert

doi:10.1530/acta.0.0360131

Cited by 23 publications

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“…Androgenic activity is again retarded during the second winter period, after which the stallion can attain its inherent potential sexual function. This second rise in androgen output would coincide with the rise in urinary oestrogens reported by other workers (Zondek, 1934;Pigon et al, 1961).…”

Section: Months Of the Yearsupporting

confidence: 72%

“…Large amounts of testosterone have been found in the spermatic vein blood of mature stallions (Lindner, 1959(Lindner, , 1961. It has also been postulated that the rise in urinary oestrogen excretion accompanies sexual maturation at 20 months (Zondek, 1934;Pigon, Lunaas & Velle, 1961). The object of the present experiment was to study sexual development in living pony stallions from birth until the time when spermatozoa appear in ejaculates, and to define the time relationship between the onset of androgenic and gametogenic testicular functions.…”

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confidence: 98%

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Puberty in the Welsh Stallion

Skinner¹,

Bowen²

1968

Reproduction

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Relatively little is known about the time when the stallion reaches puberty. In the Anglo-Norman breed the testes have been shown to increase gradually in weight from the 11th month onwards, and then more rapidly from the 16th month . Large amounts of testosterone have been found in the spermatic vein blood of mature stallions (Lindner, 1959(Lindner, , 1961. It has also been postulated that the rise in urinary oestrogen excretion accompanies sexual maturation at 20 months (Zondek, 1934;Pigon, Lunaas & Velle, 1961). The object of the present experiment was to study sexual development in living pony stallions from birth until the time when spermatozoa appear in ejaculates, and to define the time relationship between the onset of androgenic and gametogenic testicular functions. In addition, a study was made of the effects of season on puberty and semen composition.Material was provided by four Welsh stallions made available from the Unit's own herd. Three were available from birth and the fourth from the age of 15 months onwards. The foals were weaned at 6 months and clinically examined at 9 months of age (mid-winter) when the testes were very small and male behaviour was not evident. Six weeks later, with lengthening daylight, the testes were already larger and male behaviour, including masturbation, became apparent. This agrees with previous observations on the behaviour of young stallions (Hafez, Williams & Wierzbowski, 1962). The stallions were now trained to mount a teaser mare, constantly in oestrus, and ejaculate into an artificial vagina (Walton, 1938). Semen was collected at weekly intervals from the younger stallions until spermatozoa appeared in the ejaculate and from the older stallion from 15 to 27 months of age. The following were determined : volume of semen (seminal gel, if present, was included) ; sperm density in a haemocytometer; citric acid (Mann, 1964), and also time interval between entry of the stallion into the 'teaser' paddock and ejaculation (reaction time). The main results from the older stallion are illustrated in Text- fig. 1. In the three younger stallions ejaculate volume and citric acid concentration increased steadily, from 5 ml and 2 mg/100 ml at the first attempt to 9 ml and 4 mg/100 ml 4 weeks later and 18 ml and 14 mg/100 ml 12 weeks later, res¬ pectively. Reaction time was protracted at first after which a pattern developed in each animal. Reaction time became shorter as the citric acid concentration increased.The young stallions commenced ejaculating into the artificial vagina

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Section: Months Of the Yearsupporting

confidence: 72%

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confidence: 98%

Puberty in the Welsh Stallion

Skinner¹,

Bowen²

1968

Reproduction

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“…An obstacle to the determination of these trace levels of the intact sulphates is the urinary excretion by the male horse of significant amounts of the sulphate conjugates of the female sex hormones, estrone and estradiol. In eight mature stallions, Pigon et al 31. have reported that the average value for estrone was 20.7 mg/L.…”

Section: Discussionmentioning

confidence: 91%

Quantification of 19‐nortestosterone sulphate and boldenone sulphate in urine from male horses using liquid chromatography/tandem mass spectrometry

Grace

Drake

Teale

et al. 2008

Rapid Comm Mass Spectrometry

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Following administration of the anabolic steroid 19-nortestosterone or its esters to the horse, a major urinary metabolite is 19-nortestosterone-17beta-sulphate. The detection of 19-nortestosterone in urine from untreated animals has led to it being considered a naturally occurring steroid in the male horse. Recently, we have demonstrated that the majority of the 19-nortestosterone found in extracts of 'normal' urine from male horses arises as an artefact through decarboxylation of the 19-carboxylic acid of testosterone. The aim of this investigation was to establish if direct analysis of 19-nortestosterone-17beta-sulphate by liquid chromatography/tandem mass spectrometry (LC/MS/MS) had potential for the detection of 19-nortestosterone misuse in the male horse. The high concentrations of sulphate conjugates of the female sex hormones naturally present in male equine urine were overcome by selective hydrolysis of the aryl sulphates using glucuronidase from Helix pomatia; this was shown to have little or no activity for alkyl sulphates such as 19-nortestosterone-17beta-sulphate. The 'free' phenolic steroids were removed by solid-phase extraction (SPE) prior to LC/MS/MS analysis. The method also allowed for the quantification of the sulphate conjugate of boldenone, a further anabolic steroid endogenous in the male equine with potential for abuse in sports. The method was applied to the quantification of these analytes in a population of samples. This paper reports the results of that study along with the development and validation of the LC/MS/MS method. The results indicate that while 19-nortestosterone-17beta-sulphate is present at low levels as an endogenous substance in urine from 'normal' male horses, its use as an effective threshold substance may be viable.

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“…Oestrone has been obtained from pregnant mare urine (Curtis, MacCorquodale, Thayer & Doisy, 1934) and from stallion urine and testis (Beall, 1940;Pigon et al 1961 ;King et al 1966). Perfusion of a testis with [l-14C]acetate of a gonadotrophinstimulated stallion led to the formation of radioactive oestrone and oestradiol.…”

Section: Resultsmentioning

confidence: 99%

“…No progesterone could be detected on paper chromatography of an extract of 33 g. ovarian tissue of a Equilin seems to be produced only in the pregnant mare, and it has not been detec¬ ted in stallion urine, in spite of extremely high urinary levels of oestrone and oestradiol-17/? (Pigon, Lunaas & Velle, 1961). It is therefore tempting to conclude that the ring B unsaturated oestrogens are unique products of the foeto-placental unit in the horse and that their formation may be associated with the hypertrophy of the foetal gonads.…”

Section: Introductionmentioning

confidence: 99%

Formation of Steroids by the Equine Foetal Testis

MacARTHUR¹,

Short²,

O'Donnell³

1967

Journal of Endocrinology

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The testes were removed from a 9-month horse foetus and incubated with sodium [1-14C]acetate. After the addition of unlabelled steroids, the following radiochemically pure compounds were obtained: cholesterol, dehydroepiandrosterone, testosterone, androst-4-ene-3,17-dione, 17\g=a\-hydroxyprogesterone and oestrone. There was no radioactivity associated with the carrier equilenin. The yield of labelled dehydroepiandrosterone greatly exceeded that of testosterone and androst-4-ene-3,17-dione.

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Urinary Oestrogens in the Stallion

Cited by 23 publications

References 0 publications

Puberty in the Welsh Stallion

Puberty in the Welsh Stallion

Quantification of 19‐nortestosterone sulphate and boldenone sulphate in urine from male horses using liquid chromatography/tandem mass spectrometry

Formation of Steroids by the Equine Foetal Testis

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