Identification and quantification of 5α-dihydrotestosterone in the teleost fathead minnow (Pimephales promelas) by gas chromatography-tandem mass spectrometry

TY - JOUR

T1 - Identification and quantification of 5α-dihydrotestosterone in the teleost fathead minnow (Pimephales promelas) by gas chromatography-tandem mass spectrometry

AU - Margiotta-Casaluci, Luigi

AU - Courant, Frédérique

AU - Antignac, Jean Philippe

AU - Le Bizec, Bruno

AU - Sumpter, John P.

PY - 2013/9/15

Y1 - 2013/9/15

N2 - The steroid hormone 5α-dihydrotestosterone (DHT) is one of the most physiologically important androgens in male vertebrates, with the exception of teleost fish, in which it is generally assumed that DHT does not play any major physiological role. However, this assumption is challenged by the fact that all the components involved in DHT biosynthesis and action are present and evolutionary conserved in teleost fish. In fact, testosterone (T) is converted into DHT by two isoforms of the enzyme steroid-5-alpha-reductase (5αR), and both 5αRs gene expression and enzymatic activity have been detected in several tissues of different teleost species, which also have an androgen receptor with high binding affinity to DHT. This body of evidence strongly suggest that DHT is synthesised by teleost fish. We investigated this hypothesis using the cyprinid fathead minnow (Pimephales promelas) as the experimental model. The study of the evolutionary and functional conservation of 5αRs in teleost fish was used to support the experimental approach, based on an ultrasensitive gas chromatography-tandem mass spectrometry (GC-MS/MS) method to identify and measure simultaneously T and DHT in fathead minnow biological fluids and tissues. The analyses were performed using plasma samples collected from both male and female adult fish and samples of testicular tissue collected from sexually mature males. Both T and DHT were identified and quantified in all the samples analysed, and in particular, the high concentrations of DHT quantified in the testes suggested that these organs are a likely site of synthesis of DHT in the teleost fathead minnow, as they are in mammals. These results may represent the basis for future studies aimed at elucidating the physiological role, if any, of DHT in teleost fish.

AB - The steroid hormone 5α-dihydrotestosterone (DHT) is one of the most physiologically important androgens in male vertebrates, with the exception of teleost fish, in which it is generally assumed that DHT does not play any major physiological role. However, this assumption is challenged by the fact that all the components involved in DHT biosynthesis and action are present and evolutionary conserved in teleost fish. In fact, testosterone (T) is converted into DHT by two isoforms of the enzyme steroid-5-alpha-reductase (5αR), and both 5αRs gene expression and enzymatic activity have been detected in several tissues of different teleost species, which also have an androgen receptor with high binding affinity to DHT. This body of evidence strongly suggest that DHT is synthesised by teleost fish. We investigated this hypothesis using the cyprinid fathead minnow (Pimephales promelas) as the experimental model. The study of the evolutionary and functional conservation of 5αRs in teleost fish was used to support the experimental approach, based on an ultrasensitive gas chromatography-tandem mass spectrometry (GC-MS/MS) method to identify and measure simultaneously T and DHT in fathead minnow biological fluids and tissues. The analyses were performed using plasma samples collected from both male and female adult fish and samples of testicular tissue collected from sexually mature males. Both T and DHT were identified and quantified in all the samples analysed, and in particular, the high concentrations of DHT quantified in the testes suggested that these organs are a likely site of synthesis of DHT in the teleost fathead minnow, as they are in mammals. These results may represent the basis for future studies aimed at elucidating the physiological role, if any, of DHT in teleost fish.

KW - 5α-Dihydrotestosterone

KW - Androgen

KW - Fathead minnow

KW - Fish

KW - Gas chromatography-tandem mass spectrometry

KW - Testosterone

UR - http://www.scopus.com/inward/record.url?scp=84880667885&partnerID=8YFLogxK

U2 - 10.1016/j.ygcen.2013.06.017

DO - 10.1016/j.ygcen.2013.06.017

M3 - Article

AN - SCOPUS:84880667885

SN - 0016-6480

VL - 191

SP - 202

EP - 209

JO - General and Comparative Endocrinology

JF - General and Comparative Endocrinology

ER -