Ankara Üniversitesi Veteriner Fakültesi Dergisi
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Seasonal variations in serum concentrations of melatonin, testosterone, and progesterone in Arabian horse

Yıl 2009, Cilt: 56 Sayı: 1, 19 - 24, 01.03.2009

Çiğdem ALTINSAAT Aykut Göktürk ÜNER Nesrin SULU Ahmet ERGÜN

https://doi.org/10.1501/Vetfak_0000002186

Öz

The objective of this study was to characterize seasonal variations in serum concentrations of melatonin, testosterone, and progesterone in Arabian horses under natural photoperiodic conditions. Peripheral blood samples were collected during breeding and non-breeding seasons from mares and stallions. Serum concentrations of melatonin, testosterone, and progesterone were determined by radioimmunoassay. Serum concentrations of melatonin were greater in the non-breeding season (42.41±1.59 and 37.68±1.55 pg/ml) when compared to breeding season (23.52±1.24 and 17.22±2.10 pg/ml) in both mares and stallions, respectively. Melatonin concentrations were low but not different between the luteal and follicular phases during breeding season in cyclic mares. Mares had greater concentrations of melatonin than stallions in both breeding and non-breeding season. Mean concentrations of testosterone were greater during breeding season (6.58±0.50 ng/ml) than non-breeding season (3.64±0.48 ng/ml) in stallions. There was a negative correlation (r=-0.658, p<0.01) with melatonin and testosterone levels in both season in stallions. A negative correlation (r=-0.829, p<0.05) in luteal phase and a positive correlation (r=0.847, p<0.05) in non-breeding season were found between melatonin and progesterone concentrations in mares. We conclude that changes in day length act as a regulator and photoperiod can be used to modify the seasonal reproduction in Arabian horse

Anahtar Kelimeler

Arabian horse, melatonin, photoperiod, progesterone, testosterone

Kaynakça

  • Aljarrah AH (2004): Methods to Induce Earlier Onset of Cyclicity in Transitional Mares. Master's Thesis, Louisiana State University.
  • Amer HA, Shawki G, Ismail R (2008): Ovarian and endocrine changes during oestrus and early pregnancy in Arabian mares. The Internet J Vet. Med., 4, 1. Access:http://www.ispub.com/ostia/index.php?xmlFilePat h=journals/ijvm/vol4n1/mare.xml Access date: 25.05.2008.
  • Arendt J (2005): Melatonin: characteristics, concerns, and prospects. J Biol Rhythms, 20, 291-303.
  • Argo CM, Cox JE, Gray JL (1991): Effect of oral melatonin treatment on the seasonal physiology of pony stallions. J Reprod Fertil Suppl, 44, 115-125.
  • Baker FC, Driver HS (2007): Circadian rhythms, sleep, and the menstrual cycle. Sleep Med, 8, 613-622.
  • Bittman EL, Dempsey RJ, Karsch FJ (1983): Pineal melatonin secretion drives the reproductive response to day length in the ewe. Endocrinology, 113, 2276–2283.
  • Brotto LA, Barr AM, Gorzalka BB (2000): Sex differences in forced-swim and open-field test behaviours after chronic administration of melatonin. Eur J Pharmacol, 402, 87-93.
  • Clay CM, Clay JN (1992): Endocrine and testicular changes associated with season, artificial photoperiod, and the peri-pubertal period in stallions. Vet Clin North Am Equine Pract, 8, 31-56.
  • Cleaver BD, Grubaugh WR, Davis SD, Sheerin PC, Franklin KJ, Sharp DC (1991): Effect of constant light exposure on circulating gonadotrophin levels and hypothalamic gonadotrophin-releasing hormone (GnRH) content in the ovariectomized pony mare. J Reprod Fertil Suppl, 44, 259-266.
  • Cox JE, Redhead PH, Jawad NM (1988): The effect of artificial photoperiod at the end of the breeding season on plasma testosterone concentrations in stallions. Aust Vet J, 65, 239-241.
  • Diekman MA, Braun W, Peter D, Cook D (2002): Seasonal serum concentrations of melatonin in cycling and noncycling mares. J Anim Sci, 80, 2949-2952.
  • Ferreira-Dias G, Claudino F, Carvalho H, Agrícola R, Alpoim-Moreira J, Robalo Silva J (2005): Seasonal reproduction in the mare: possible role of plasma leptin, body weight and immune status. Domest Anim Endocrinol, 29, 203-213.
  • Fitzgerald BP, Davison LA, McManus CJ (2000): Evidence for a seasonal variation in the ability of exogenous melatonin to suppress prolactin secretion in the mare. Domest Anim Endocrinol, 18, 395-408.
  • Fitzgerald BP, McManus CJ (2000): Photoperiodic versus metabolic signals as determinants of seasonal anestrus in the mare. Biol Reprod, 63, 335-340.
  • Freedman LJ, Garcia MC, Ginther OJ (1979): Influence of photoperiod and ovaries on seasonal reproductive activity in mares. Biol Reprod, 20, 567-574.
  • Gerlach T, Aurich JE (2000): Regulation of seasonal reproductive activity in the stallion, ram and hamster. Anim Reprod Sci, 58, 197-213.
  • Guerin MV, Deed JR, Kennaway DJ, Matthews CD (1995): Plasma melatonin in the horse: measurements in natural photoperiod and in acutely extended darkness throughout the year. J Pineal Res, 19, 7-15.
  • Guillaume D, Rio N, Toutain PL (1995): Kinetic studies and production rate of melatonin in pony mares. Am J Physiol, 268, 1236-1241.
  • Guillaume D, Zarazaga LA, Malpaux B, Chemineau P (2006): Variability of plasma melatonin level in pony mares (Equus caballus), comparison with the hybrid: mules and with jennies (Equus asinus). Reprod Nutr Dev, 46, 633-639.
  • Hill MN, Brotto LA, Lee TT, Gorzalka BB (2003): Corticosterone attenuates the antidepressant-like effects elicited by melatonin in the forced swim test in both male and female rats. Prog Neuropsychopharmacol Biol Psychiatry, 27, 905-911.
  • Hodge SL, Kreider JL, Potter GD, Harms PG, Fleeger JL (1982): Influence of photoperiod on the pregnant and postpartum mare. Am J Vet Res, 43, 1752-1755.
  • Holtan DW, Nett TM, Estergreen VL (1975): Plasma progestins in pregnant, postpartum and cycling mares. J Anim Sci, 40, 251-260.
  • Johnson L, Thompson DL Jr (1983): Age-related and seasonal variation in the Sertoli cell population, daily sperm production and serum concentrations of follicle- stimulating hormone, luteinizing hormone and testosterone in stallions. Biol Reprod, 29, 777-789.
  • Keefe DL, Turek FW (1985): Circadian time keeping processes in mammalian reproduction. Oxf Rev Reprod Biol, 7, 346-400.
  • Kilmer DM, Sharp DC, Bergland LA, Grubaugh W, McDowell KJ, Peck LS (1982) Melatonin rhythms in pony mares and foals. J Reprod (Fertil) Suppl, 32, 303–307.
  • Kooistra LH, Ginther OJ (1975): Effect of photoperiod on reproductive activity and hair in mares. Am J Vet Res, 36, 1413-1419.
  • Larkin JE, Jones J, Zucker I (2002): Temperature dependence of gonadal regression in Syrian hamsters exposed to short day lengths. Am J Physiol Regul Integr Comp Physiol, 282, 744-752.
  • Matthews CD, Guerin MV, Deed JR (1993): Melatonin and photoperiodic time measurement: Seasonal breeding in the sheep. J Pineal Res 14, 105–116.
  • McKinnon AO, Voss JL (1993): Equine Reproduction. Wiley-Blackwell, USA.
  • Nagy P, Guillaume D, Daels P (2000): Seasonality in mares. Anim Reprod Sci, 60-61, 245-262.
  • Oxender WD, Noden PA, Hafs HD (1977): Estrus, ovulation, and serum progesterone, estradiol, and LH concentrations in mares after an increased photoperiod during winter. Am J Vet Res, 38, 203-207.
  • Peltier MR, Robinson G, Sharp DC (1998): Effects of melatonin implants in pony mares. 2. Long-term effects. Theriogenology, 49, 1125-1142.
  • Sharp DC, Grubaugh WR, Zavy MT, Vernon MW (1980): Seasonal variation in melatonin secretory patterns in mares. J Anim Sci, 51, 327.
  • Sharp DC, Grubaugh WR, Weithenauer J, Davis SD, Wilcox CJ (1991): Effects of steroid administration on pituitary luteinizing hormone and follicle-stimulating hormone in ovariectomized pony mares in the early spring: pituitary responsiveness to gonadotropin-releasing hormone and pituitary gonadotropin content. Biol Reprod, 44, 983-90.
  • Stankov B, Cozzi B, Lucini V, Fumagalli P, Scaglione F, Fraschini F (1991): Characterization and mapping of melatonin receptors in the brain of three mammalian species: rabbit, horse and sheep. A comparative in vitro binding study. Neuroendocrinology, 53, 214-221.
  • Storer WA (2002): The Effects of Growth Hormone or Melatonin on the Reproductive Axis of Stallions. Master's Thesis, Louisiana State University.
  • Tamarkin L, Westrom WK, Hamill AI, Goldman BD (1976): Effect of melatonin on the reproductive systems of male and female Syrian hamsters: a diurnal rhythm in sensitivity to melatonin. Endocrinology, 99, 1534-1541.
  • Thompson DL Jr, Pickett BW, Berndtson WE, Voss JL, Mett TM (1977): Reproductive physiology of the stallion. VIII. Artificial photoperiod, collection interval and seminal characteristics, sexual behavior and concentrations of LH and testosterone in serum. J Anim Sci, 44, 656-664.
  • Thompson DL Jr, St George RL, Jones LS, Garza F Jr (1985): Patterns of secretion of luteinizing hormone, follicle stimulating hormone and testosterone in stallions during the summer and winter. J Anim Sci, 60, 741-748.

Arap atlarında serum melatonin, testosteron ve progesteron seviyelerinin mevsimsel değişimleri

Yıl 2009, Cilt: 56 Sayı: 1, 19 - 24, 01.03.2009

Çiğdem ALTINSAAT Aykut Göktürk ÜNER Nesrin SULU Ahmet ERGÜN

https://doi.org/10.1501/Vetfak_0000002186

Öz

Bu çalışmanın amacı, doğal fotoperiyodik koşullarda Arap atlarının serum melatonin, testosteron ve progesteron seviyelerinin mevsimsel değişimlerini belirlemektir. Kısrak ve aygırlardan üreme döneminde ve üremenin olmadığı dönemde toplanan kan örneklerinden, radioimmunoassay yöntemi ile serum melatonin, testosteron ve progesteron seviyeleri belirlenmiştir. Sırasıyla hem kısrak hem de aygırlarda melatonin seviyeleri üremenin olmadığı dönemde (42.41±1.59 ve 37.68±1.55 pg/ml) üreme dönemine göre (23.52±1.24 ve 17.22±2.10 pg/ml) daha yüksek bulunmuştur. Üreme döneminde östrus siklusu gösteren kısraklarda melatonin seviyelerinin düşük fakat luteal ve foliküler dönemler arasında fark yoktu. Kısraklar hem üreme döneminde hem de üremenin olmadığı dönemde aygırlara göre daha yüksek melatonin seviyelerine sahipti. Aygırlarda üreme dönemindeki (6.58±0.50 ng/ml) testosteron seviyeleri üremenin olmadığı dönemden (3.64±0.48 ng/ml) daha yüksekti. Aygırlarda her iki dönemde melatonin ile testosteron seviyeleri arasında negatif bir ilişki vardı (r=-0.658, p<0.01). Kısrakların melatonin ve progesteron seviyeleri arasında ise luteal dönemde negatif (r=-0.829, p<0.05), üremenin olmadığı dönemde de pozitif bir ilişki (r=0.847, p<0.05) bulundu Bu çalışma ile Arap atlarında, gün uzunluğundaki değişikliklerin mevsimsel üremede bir düzenleyici olarak görev aldığı ve fotoperiyodun bu düzenlemede değiştirici etkisi olduğu bulundu

Anahtar Kelimeler

Arap atı, fotoperiyod, melatonin, progesteron, testosteron

Kaynakça

  • Aljarrah AH (2004): Methods to Induce Earlier Onset of Cyclicity in Transitional Mares. Master's Thesis, Louisiana State University.
  • Amer HA, Shawki G, Ismail R (2008): Ovarian and endocrine changes during oestrus and early pregnancy in Arabian mares. The Internet J Vet. Med., 4, 1. Access:http://www.ispub.com/ostia/index.php?xmlFilePat h=journals/ijvm/vol4n1/mare.xml Access date: 25.05.2008.
  • Arendt J (2005): Melatonin: characteristics, concerns, and prospects. J Biol Rhythms, 20, 291-303.
  • Argo CM, Cox JE, Gray JL (1991): Effect of oral melatonin treatment on the seasonal physiology of pony stallions. J Reprod Fertil Suppl, 44, 115-125.
  • Baker FC, Driver HS (2007): Circadian rhythms, sleep, and the menstrual cycle. Sleep Med, 8, 613-622.
  • Bittman EL, Dempsey RJ, Karsch FJ (1983): Pineal melatonin secretion drives the reproductive response to day length in the ewe. Endocrinology, 113, 2276–2283.
  • Brotto LA, Barr AM, Gorzalka BB (2000): Sex differences in forced-swim and open-field test behaviours after chronic administration of melatonin. Eur J Pharmacol, 402, 87-93.
  • Clay CM, Clay JN (1992): Endocrine and testicular changes associated with season, artificial photoperiod, and the peri-pubertal period in stallions. Vet Clin North Am Equine Pract, 8, 31-56.
  • Cleaver BD, Grubaugh WR, Davis SD, Sheerin PC, Franklin KJ, Sharp DC (1991): Effect of constant light exposure on circulating gonadotrophin levels and hypothalamic gonadotrophin-releasing hormone (GnRH) content in the ovariectomized pony mare. J Reprod Fertil Suppl, 44, 259-266.
  • Cox JE, Redhead PH, Jawad NM (1988): The effect of artificial photoperiod at the end of the breeding season on plasma testosterone concentrations in stallions. Aust Vet J, 65, 239-241.
  • Diekman MA, Braun W, Peter D, Cook D (2002): Seasonal serum concentrations of melatonin in cycling and noncycling mares. J Anim Sci, 80, 2949-2952.
  • Ferreira-Dias G, Claudino F, Carvalho H, Agrícola R, Alpoim-Moreira J, Robalo Silva J (2005): Seasonal reproduction in the mare: possible role of plasma leptin, body weight and immune status. Domest Anim Endocrinol, 29, 203-213.
  • Fitzgerald BP, Davison LA, McManus CJ (2000): Evidence for a seasonal variation in the ability of exogenous melatonin to suppress prolactin secretion in the mare. Domest Anim Endocrinol, 18, 395-408.
  • Fitzgerald BP, McManus CJ (2000): Photoperiodic versus metabolic signals as determinants of seasonal anestrus in the mare. Biol Reprod, 63, 335-340.
  • Freedman LJ, Garcia MC, Ginther OJ (1979): Influence of photoperiod and ovaries on seasonal reproductive activity in mares. Biol Reprod, 20, 567-574.
  • Gerlach T, Aurich JE (2000): Regulation of seasonal reproductive activity in the stallion, ram and hamster. Anim Reprod Sci, 58, 197-213.
  • Guerin MV, Deed JR, Kennaway DJ, Matthews CD (1995): Plasma melatonin in the horse: measurements in natural photoperiod and in acutely extended darkness throughout the year. J Pineal Res, 19, 7-15.
  • Guillaume D, Rio N, Toutain PL (1995): Kinetic studies and production rate of melatonin in pony mares. Am J Physiol, 268, 1236-1241.
  • Guillaume D, Zarazaga LA, Malpaux B, Chemineau P (2006): Variability of plasma melatonin level in pony mares (Equus caballus), comparison with the hybrid: mules and with jennies (Equus asinus). Reprod Nutr Dev, 46, 633-639.
  • Hill MN, Brotto LA, Lee TT, Gorzalka BB (2003): Corticosterone attenuates the antidepressant-like effects elicited by melatonin in the forced swim test in both male and female rats. Prog Neuropsychopharmacol Biol Psychiatry, 27, 905-911.
  • Hodge SL, Kreider JL, Potter GD, Harms PG, Fleeger JL (1982): Influence of photoperiod on the pregnant and postpartum mare. Am J Vet Res, 43, 1752-1755.
  • Holtan DW, Nett TM, Estergreen VL (1975): Plasma progestins in pregnant, postpartum and cycling mares. J Anim Sci, 40, 251-260.
  • Johnson L, Thompson DL Jr (1983): Age-related and seasonal variation in the Sertoli cell population, daily sperm production and serum concentrations of follicle- stimulating hormone, luteinizing hormone and testosterone in stallions. Biol Reprod, 29, 777-789.
  • Keefe DL, Turek FW (1985): Circadian time keeping processes in mammalian reproduction. Oxf Rev Reprod Biol, 7, 346-400.
  • Kilmer DM, Sharp DC, Bergland LA, Grubaugh W, McDowell KJ, Peck LS (1982) Melatonin rhythms in pony mares and foals. J Reprod (Fertil) Suppl, 32, 303–307.
  • Kooistra LH, Ginther OJ (1975): Effect of photoperiod on reproductive activity and hair in mares. Am J Vet Res, 36, 1413-1419.
  • Larkin JE, Jones J, Zucker I (2002): Temperature dependence of gonadal regression in Syrian hamsters exposed to short day lengths. Am J Physiol Regul Integr Comp Physiol, 282, 744-752.
  • Matthews CD, Guerin MV, Deed JR (1993): Melatonin and photoperiodic time measurement: Seasonal breeding in the sheep. J Pineal Res 14, 105–116.
  • McKinnon AO, Voss JL (1993): Equine Reproduction. Wiley-Blackwell, USA.
  • Nagy P, Guillaume D, Daels P (2000): Seasonality in mares. Anim Reprod Sci, 60-61, 245-262.
  • Oxender WD, Noden PA, Hafs HD (1977): Estrus, ovulation, and serum progesterone, estradiol, and LH concentrations in mares after an increased photoperiod during winter. Am J Vet Res, 38, 203-207.
  • Peltier MR, Robinson G, Sharp DC (1998): Effects of melatonin implants in pony mares. 2. Long-term effects. Theriogenology, 49, 1125-1142.
  • Sharp DC, Grubaugh WR, Zavy MT, Vernon MW (1980): Seasonal variation in melatonin secretory patterns in mares. J Anim Sci, 51, 327.
  • Sharp DC, Grubaugh WR, Weithenauer J, Davis SD, Wilcox CJ (1991): Effects of steroid administration on pituitary luteinizing hormone and follicle-stimulating hormone in ovariectomized pony mares in the early spring: pituitary responsiveness to gonadotropin-releasing hormone and pituitary gonadotropin content. Biol Reprod, 44, 983-90.
  • Stankov B, Cozzi B, Lucini V, Fumagalli P, Scaglione F, Fraschini F (1991): Characterization and mapping of melatonin receptors in the brain of three mammalian species: rabbit, horse and sheep. A comparative in vitro binding study. Neuroendocrinology, 53, 214-221.
  • Storer WA (2002): The Effects of Growth Hormone or Melatonin on the Reproductive Axis of Stallions. Master's Thesis, Louisiana State University.
  • Tamarkin L, Westrom WK, Hamill AI, Goldman BD (1976): Effect of melatonin on the reproductive systems of male and female Syrian hamsters: a diurnal rhythm in sensitivity to melatonin. Endocrinology, 99, 1534-1541.
  • Thompson DL Jr, Pickett BW, Berndtson WE, Voss JL, Mett TM (1977): Reproductive physiology of the stallion. VIII. Artificial photoperiod, collection interval and seminal characteristics, sexual behavior and concentrations of LH and testosterone in serum. J Anim Sci, 44, 656-664.
  • Thompson DL Jr, St George RL, Jones LS, Garza F Jr (1985): Patterns of secretion of luteinizing hormone, follicle stimulating hormone and testosterone in stallions during the summer and winter. J Anim Sci, 60, 741-748.

Ayrıntılar

Birincil Dil İngilizce
Konular Veteriner Cerrahi
Diğer ID JA46MH89DY
Bölüm Araştırma Makalesi
Yazarlar

Çiğdem ALTINSAAT
Department of Physiology, Faculty of Veterinary Medicine, University of Ankara, Ankara, Turkey

Aykut Göktürk ÜNER
Department of Physiology, Faculty of Veterinary Medicine, University of Ankara, Ankara, Turkey

Nesrin SULU
Department of Physiology, Faculty of Veterinary Medicine, University of Ankara, Ankara, Turkey

Ahmet ERGÜN
Department of Physiology, Faculty of Veterinary Medicine, University of Ankara, Ankara, Turkey

Yayımlanma Tarihi 1 Mart 2009
Yayınlandığı Sayı Yıl 2009Cilt: 56 Sayı: 1

Kaynak Göster

Bibtex @editöre mektup { auvfd556747, journal = {Ankara Üniversitesi Veteriner Fakültesi Dergisi}, issn = {1300-0861}, eissn = {1308-2817}, address = {}, publisher = {Ankara Üniversitesi}, year = {2009}, volume = {56}, number = {1}, pages = {19 - 24}, doi = {10.1501/Vetfak\_0000002186}, title = {Seasonal variations in serum concentrations of melatonin, testosterone, and progesterone in Arabian horse}, key = {cite}, author = {Altınsaat, Çiğdem and Üner, Aykut Göktürk and Sulu, Nesrin and Ergün, Ahmet} }
APA Altınsaat, Ç. , Üner, A. G. , Sulu, N. & Ergün, A. (2009). Seasonal variations in serum concentrations of melatonin, testosterone, and progesterone in Arabian horse . Ankara Üniversitesi Veteriner Fakültesi Dergisi , 56 (1) , 19-24 . DOI: 10.1501/Vetfak_0000002186
MLA Altınsaat, Ç. , Üner, A. G. , Sulu, N. , Ergün, A. "Seasonal variations in serum concentrations of melatonin, testosterone, and progesterone in Arabian horse" . Ankara Üniversitesi Veteriner Fakültesi Dergisi 56 (2009 ): 19-24 <http://vetjournal.ankara.edu.tr/tr/pub/issue/44758/556747>
Chicago Altınsaat, Ç. , Üner, A. G. , Sulu, N. , Ergün, A. "Seasonal variations in serum concentrations of melatonin, testosterone, and progesterone in Arabian horse". Ankara Üniversitesi Veteriner Fakültesi Dergisi 56 (2009 ): 19-24
RIS TY - JOUR T1 - Arap atlarında serum melatonin, testosteron ve progesteron seviyelerinin mevsimsel değişimleri AU - ÇiğdemAltınsaat, Aykut GöktürkÜner, NesrinSulu, AhmetErgün Y1 - 2009 PY - 2009 N1 - doi: 10.1501/Vetfak_0000002186 DO - 10.1501/Vetfak_0000002186 T2 - Ankara Üniversitesi Veteriner Fakültesi Dergisi JF - Journal JO - JOR SP - 19 EP - 24 VL - 56 IS - 1 SN - 1300-0861-1308-2817 M3 - doi: 10.1501/Vetfak_0000002186 UR - https://doi.org/10.1501/Vetfak_0000002186 Y2 - 2023 ER -
EndNote %0 Ankara Üniversitesi Veteriner Fakültesi Dergisi Seasonal variations in serum concentrations of melatonin, testosterone, and progesterone in Arabian horse %A Çiğdem Altınsaat , Aykut Göktürk Üner , Nesrin Sulu , Ahmet Ergün %T Seasonal variations in serum concentrations of melatonin, testosterone, and progesterone in Arabian horse %D 2009 %J Ankara Üniversitesi Veteriner Fakültesi Dergisi %P 1300-0861-1308-2817 %V 56 %N 1 %R doi: 10.1501/Vetfak_0000002186 %U 10.1501/Vetfak_0000002186
ISNAD Altınsaat, Çiğdem , Üner, Aykut Göktürk , Sulu, Nesrin , Ergün, Ahmet . "Seasonal variations in serum concentrations of melatonin, testosterone, and progesterone in Arabian horse". Ankara Üniversitesi Veteriner Fakültesi Dergisi 56 / 1 (Mart 2009): 19-24 . https://doi.org/10.1501/Vetfak_0000002186
AMA Altınsaat Ç. , Üner A. G. , Sulu N. , Ergün A. Seasonal variations in serum concentrations of melatonin, testosterone, and progesterone in Arabian horse. Ankara Univ Vet Fak Derg. 2009; 56(1): 19-24.
Vancouver Altınsaat Ç. , Üner A. G. , Sulu N. , Ergün A. Seasonal variations in serum concentrations of melatonin, testosterone, and progesterone in Arabian horse. Ankara Üniversitesi Veteriner Fakültesi Dergisi. 2009; 56(1): 19-24.
IEEE Ç. Altınsaat , A. G. Üner , N. Sulu ve A. Ergün , "Seasonal variations in serum concentrations of melatonin, testosterone, and progesterone in Arabian horse", Ankara Üniversitesi Veteriner Fakültesi Dergisi, c. 56, sayı. 1, ss. 19-24, Mar. 2009, doi:10.1501/Vetfak_0000002186