Relationship between ghrelin and estrogen in the ovary of pregnant sheep

Document Type : Reproduction


1 Department of Clinical Sciences, School of Veterinary Medicine, Lorestan University, P. O. Box: 465, Khorramabad, Iran

2 Division of Biochemistry, School of Veterinary Medicine, Lorestan University, P. O. Box: 465, Khorram Abad, Iran


Background:Ghrelin, an endogenous ligand for the growth
secretagogue receptor is predominantly produced in the stomach and an
expression of ghrelin has recently been identified in placenta and ovary.
OBJECTIVES: Therefore, we decited to measure ovarian ghrelin as quantitative and
evaluate the correlation between ghrelin and estrogen during second half of
ovine pregnancy.
METHODS: The ovarian samples were collected from 40
pregnant sheep in 3, 3.5, 4, 4.5 and 5 months of pregnancy in a local abattoir.
Follicles and active corpora lutea (CL) were dissected from surrounding
tissues, separately. The samples were homogenized with phosphate buffer (0.1 M,
pH=7.4) on liquid nitrogen to provide fluid samples. Ghrelin and estrogen
concentrations were measured by ELISA method and expressed as milligram (mg)
and picogram (pg) per mg of tissue protein, respectively.
There was a linear correlation between ghrelin and estrogen in ovarian follicles
(r=0.97 and p=0.004), but not in CL. Follicular ghrelin significantly increased
in 4, 4.5 and 5 months (p<0.001) but CL ghrelin significantly decreased in
the 4.5 month of ovine pregnancy (p<0.01). Estrogen concentration was also
significantly higher in 4-5 months of pregnancy in ovarian follicles
(p<0.001) but potent CL indicated higher estrogen level only in the 5th
month of pregnancy (p<0.001).
These results emphasize the role of ghrelin in
the reproductive system and open a new window to future studies


Article Title [Persian]

رابطه بین گرلین و استروژن در تخمدان گوسفندان آبستن

Authors [Persian]

  • علی سوخته زاری 1
  • مسعود علیرضایی 2
1 گروه علوم درمانگاهی دانشکده دامپزشکی دانشگاه لرستان، صندوق پستی 465، خرم آباد، ایران
2 بخش بیوشیمی دانشکده دامپزشکی دانشگاه لرستان، صندوق پستی 465، خرم آباد، ایران
Abstract [Persian]

زمینه مطالعه: گرلین، بعنوان یک لیگاند داخلی برای گیرنده ترشحی رشد بطور غالب در معده تولید می‌گردد و اخیراً بیان گرلین در جفت و تخمدان گزارش شده است. هدف: بنابراین ما تصمیم گرفتیم که گرلین تخمدانی را بصورت کمی ارزیابی و رابطه گرلین و استروژن را در طول نیمه دوم آبستنی در گوسفند بررسی کنیم. روش کار: نمونه‌های تخمدان از 40 میش آبستن در 3، 5/3، 4، 5/4 و 5 ماهگی از آبستنی در یک کشتارگاه محلی جمع آوری شدند. فولیکول‌ها و جسم زرد فعال از بافت‌های اطراف بصورت جداگانه تهیه گردیدند. نمونه ها با استفاده از بافر فسفات (یک دهم مولار با 7.40= pH)  بر روی ازت مایع هموژنیزه شدند تا نمونه‌های مایع بدست آید. غلظت گرلین و استروژن بوسیله روش الیزا اندازه‌گیری شد و بترتیب بصورت میلی گرم و پیکوگرم در میلی گرم از پروتئین بافت برای گرلین و استروژن بیان گردید. نتایج: یک رابطه خطی بین گرلین و استروژن در فولیکول‌های تخمدان وجود داشت ( 0.97=r,0.004=p) اما در جسم زرد این رابطه نبود. گرلین فولیکول‌ها بطور معنی‌داری در 4، 5/4 و 5 ماهگی افزایش یافت (0.001>p) ولی گرلین جسم زرد بطور معنی‌داری در 5/4 ماهگی از آبستنی گوسفند کاهش یافت (0.01>p). در فولیکول‌های تخمدان همچنین غلظت استروژن در 5-4 ماهگی آبستنی بالا بود (0.001>p) اما جسم زرد فعال فقط در 5 ماهگی غلظت استروژن بالاتری نشان داد (0.001>p). نتیجه گیری نهایی: این نتایج نقش گرلین را در سیستم تولید مثل برجسته می‌کند و دریچه جدیدی رو به مطالعات آینده باز می‌کند.

Keywords [Persian]

  • جسم زرد
  • استروژن
  • فولیکول
  • گرلین
  • گوسفند
Al-Gubory, K.H., Driancourt, M.A., Antoine, M., Martal, J., Neimer, N. (1994) Evidence that a non-steroidal factor from corpus luteum of pregnant sheep inhibits aromatase activity of ovarian follicles in vitro. J Reprod Fertil 100: 51-56.
Alirezaei, M., Dezfoulian, O., Kheradmand, A. (2015) Novel Antioxidant properties of ghrelin and oleuropein versus lipopolysaccharide-mediated renal failure in rats. Int J Pept Res Ther 21: 411-421.
Caminos, J.E., Tena-Sempere, M., Gaytán, F., Sanchez-Criado, J.E., Barreiro, M.L., Nogueiras, R., Casanueva, F.F., Aguilar, E., Diéguez, C. (2003) Expression of ghrelin in the cyclic and pregnant rat ovary. Endocrinology. 144: 1594-602.
Du, C., Li, H., Cao, G., Xilingaowa, Wang, C., Li, C. (2010) Expression of the orexigenic peptide ghrelin and the type 1a growth hormone secretagogue receptor in sheep oocytes and pre-implantation embryos produced in vitro. Reprod Domest Anim. 45: 92-8.
Du, C., Xilingaowa, Cao. G., Wang, C., Li, H., Zhao. Y., Cao, S., Cao, J. (2009) Expression of the orexigenic peptide ghrelin in the sheep ovary. Domest Anim Endocrinol. 36: 89-98.
Dupont, J., Maillard, V., Coyral-Castel, S., Rame, C., Froment, P. (2010) Ghrelin in Female and Male Reproduction. Int J Pept, A rticle ID 158102, 8 pages.
Gambineri, A., Pagotto, U., Tschop, M., Vicennati, V., Manicardi, E., Carcello, A., Cacciari, M., De Iasio, R., Pasquali, R. (2003) Anti-androgen treatment increases circulating ghrelin levels in obese women with polycystic ovary syndrome. J Endocrinol Invest. 26: 629-634.
Garcia, M.C., Lopez, M., Alvarez, C.V., Casanueva, F.F., Tena-Sempere, M., Diéguez, C. (2007) Role of ghrelin in reproduction. Reproduction. 133: 531-540.
Gaytan, F., Barreiro, M.L., Chopin, L.K., Herington, A.C., Morales, C., Pinilla, L., Casanueva, F.F., Aguilar, E., Diéguez, C., Tena-Sempere, M. (2003) Immunolocalization of ghrelin and its functional receptor, the type 1a growth hormone secretagogue receptor, in the cyclic human ovary, J Clin Endocrinol Metab. 88: 879-887.
Gnanapavan S., Kola, B., Bustin, S.A., Morris, D.G., McGee, P., Fairclough, P., Bhattacharya, S., Carpenter, R., Grossman, A.B., Korbonits, M. (2002) The tissue distribution of the mRNA of ghrelin and subtypes of its receptor, GHS-R, in humans. J Clin Endocrinol Metab. 87: 2988-2990.
Gregoraszczuk, E.L., Bylica, A., Gertler, A. (2000) Response of porcine theca and granulosa cells to GH during short-term in vitro culture. Anim Reprod Sci. 58: 113-125.
Gualillo, O., Lago, F., Gomez-Reino, J., Casanueva, F.F., Dieguez, C. (2003) Ghrelin a widespread hormone: insights into molecular and cellular regulation of its expression and mechanism of action, FEBS Lett. 552: 105-109.
Harrison, J.L., Adam, C.L., Brown, Y.A., Wallace., J.M., Aitken, R.P., Lea RG., Miller, DW. (2007) an immunohistochemical of the localization developmental expression of ghrelin and its functional receptor in the ovine placenta. Reprod Biol Endocrinol. 5: 25-32.
Kheradmand, A., Alirezaei, M., Birjandi, M. (2010) Ghrelin promotes antioxidant enzyme activity and reduces lipid peroxidation in the rat ovary. Regul Pept. 162: 84-89.
Kheradmand, A., Dezfoulian, O., Tarrahi, M.J. (2011) Ghrelin attenuates heat-induced degenerative effects in the rat testis. Regul Pept. 167: 97-104.
Kojima, M., Kangawa, K. (2005) Ghrelin: structure and function. Physiol Rev. 85: 495-522.
Lowry, O.H., Rosebrough, N.J., Farr, A.L., Randal, R.J. (1951) Protein measurement with the Folin phenol reagent. J Biol Chem. 193: 265-275.
Lu, J.K., Judd, H.L. (1982) Silastic implants of progesterone produce high circulating levels of both progesterone and 20 alpha-hydroxyprogesterone in ovariectomized, adrenalectomized rats. Biol Reprod. 26: 385-390.
Miller, D.W., Harrison, J.L., Brown, Y.A., Doyle, U., Lindsay, A., Adam, C.L., Lea, RG. (2005) Immunohistochemical evidence for an endocrine/paracrine role for ghrelin in the reproductive tissues of sheep. Reprod Biol Endocrinol. 3: 60-65.
Neamati, S., Alirezaei, M., Kheradmand, A. (2011) Ghrelin acts as an antioxidant agent in the rat kidney. Int J Pept Res Ther. 17: 239-245.
Obay, B.D., Tasdemir, E., Tumer, Cl., Bilgin, HM., Atmaca, M. (2008) Dose dependent effects of ghrelin on pentylenetetrazole-induced oxidative stress in a rat seizure model. Peptides. 29: 448-455.
Pagotto, U., Gambineri, A., Vicennati, V., Heiman, M.L., Tschop, M., Pasquali, R. (2002) Plasma ghrelin, obesity, and the polycystic ovary syndrome: correlation with insulin resistance and androgen levels. J Clin Endocrinol Metab. 87: 5625-5629.
Rak, A., Gregoraszczuk, EŁ. (2008) Local feedback loop of ghrelin-GH in the pig ovary: Action on estradiol secretion, aromatase activity and cell apoptosis. Growth Hormone IGF Res. 18: 221-227.
Sakata, I., Tanaka, T., Yamazaki, M., Tanizaki, T., Zheng, Z., Sakai, T. (2006) Gastric estrogen directly induces ghrelin expression and production in the rat stomach. J Endocrinol. 190: 749-757.
Sirotkin, A.V., Grossmann, R., Mar´ıa-Peon, M.T., Roa, J., Tena-Sempere, M., Klein, S. (2006) Novel expression and functional role of ghrelin in chicken ovary. Mol Cell Endocrinol. 257-258: 15-25.
Sivachelvan, M.N., Ali, M.G., Chibuzo, G.A. (1996) Fetal age estimation in sheep and goats. Small Rumin Res. 19: 69-76.
Sokhtehzari, A., Alirezaei M., Mirzaei, A., Neamati, Sh. (2011) Ovarian and placental P450‐aromatase activity during second half of ovine pregnancy. Online J Vet Res. 15: 381-389.
Zhang, W., Lei, Z., Su, J., Chen, S. (2008) Expression of ghrelin in the porcine hypothalamo-pituitary-ovary axis during the estrous cycle. Anim Reprod Sci. 109: 356-367.