Changes of Leptin and Ghrelin Levels in the Early Lactation Period After Birth in Sheep

Öz

Lactation is a period, which involves important changes of energy metabolism in ruminants. Leptin and ghrelin are hormones that play a critical role in the regulation of energy homeostasis. In this study we investigated levels of leptin and ghrelin hormones, which have roles on changes of energy metabolism, during early lactation period in sheep. Leptin and ghrelin levels of 10 sheep after birth were measured at the 4th and 6th weeks of the early lactation period. Hormone measurements were analyzed with using specific commercial ELISA kits. Leptin and Ghrelin levels were significantly lower in the 4th week than in the 6th week (P<0.05). There was also a high level of significant correlation between leptin and ghrelin levels. These results have shown that leptin and ghrelin peptides play a role in metabolism in response to energy changes in the early lactation and are simultaneously decreasing or increasing. This may be related to increased energy needs, weight loss, mobilization of adipose tissue lipids, or other hormonal regulatory mechanisms involved in energy metabolism as well as birth and postpartum breastfeeding.

Anahtar Kelimeler

• Early Lactation,Ghrelin,Leptin,Sheep

Koyunlarda Doğum Sonrası Erken Laktasyon Döneminde Leptin ve Ghrelin Seviyelerin Değişimleri

Öz

Laktasyon, ruminantlarda enerji metabolizmasında önemli değişimlerin olduğu bir dönemdir. Leptin ve ghrelin enerji homeostazisinin düzenlenmesinde kritik rol oynayan hormonlardır. Bu çalışmada koyunlarda erken laktasyon döneminde oluşan enerji metabolizması değişimlerinde görev alan leptin ve ghrelin hormon seviyeleri incelendi. Hormon ölçümleri spesifik ticari elisa kitleri kullanılarak belirlendi. Doğumdan sonra 10 koyunun erken laktasyon döneminin 4. ve 6. haftalarındaki plazma leptin ve ghrelin seviyeleri ölçüldü. Leptin ve Ghrelin düzeyleri 4. haftada 6. haftaya göre anlamlı olarak düşük bulunduğu gözlendi (P<0.05). Ayrıca 6. haftada bu seviyelerin arttığı gözlendi. Ayrıca leptin ve ghrelin seviyeleri arasında yüksek düzeyde anlamlı korelasyon tespit edildi. Bu sonuçlar leptin ve ghrelin peptitlerinin erken laktasyonda meydana gelen enerji değişimlerine cevaben metabolizmada birlikte rol oynadıkları ve eş zamanlı azalıp arttıklarını göstermiştir. Bu durum doğum ve doğum sonrası emzirme ile beraber, artan enerji ihtiyacı, kilo kayıpları ve adipoz dokudaki lipitlerin mobilizasyonu ya da enerji metabolizmasında görev alan başka hormonal düzenleme mekanizmaları ile ilgili olabilir.

Anahtar Kelimeler

• Erken Laktasyon,Ghrelin,Koyun,Leptin

Kaynakça

1. 1. Kojima M., Hosoda H., Date Y., Nakazato M., Matsuo H., Kangawa K., 1999. Ghrelin is a growth-hormone-releasing acylated peptide from stomach. Nature, 402, 656-60.
2. 2. Zizzari P., Hassouna R., Grouselle D., Epelbaum J., Tolle V., 2011. Physiological roles of preproghrelin-derived peptides in GH secretion and feeding. Peptides, 32, 2274-2282.
3. 3. Nakazato M., Murakami N., Date Y., Kojima M., Matsuo H., Kangawa K., Matsukura S., 2001. A role for ghrelin in the central regulation of feding. Nature, 409, 194-19.
4. 4. Tschop M, Smiley DL, Heiman ML., 2000. Ghrelin induces adiposity in rodents. Nature, 407, 908-913.
5. 5. Cummings DE., Shannon MH., 2003. Roles for ghrelin in the regulation of appetite and body weight. Archives of Surgery, 138, 389-396.
6. 6. Hayashida T., Murakami K., Mogi K., Nishihara M., Nakazato M., Mondal M.S., Horii Y., Kojima M., Kangawa K., Murakami N., 2001. Ghrelin in domestic animals: distribution in stomach and its possible role. Domestic Animal Endocrinology, 21, 17-24.
7. 7. Gentry PC., Willey JP., Collier RJ., 2003 Ghrelin, a growth hormone secretagogue, is xpressed by bovine rumen. J. Anim. Sci, 81, 123.
8. 8. Delavaud C., Ferlay A., Faulconnier Y., Bocquier F., Kann G., Chilliard, Y., 2002. Plasma leptin concentration in adult cattle: effects of breed, adiposity, feeding level, and meal intake. J. Anim. Sci, 80: 1317-1328.

9. 9. Tokuda T., Kimura D., Fujihara T., 2001. The relationships between leptin and insulin in blood plasma of growing lambs. Anim. Sci, 73, 71-76.
10. 10. Tokuda T., Delavaud C., Chilliard Y., 2002. Effect of dietary energy levels on plasma leptin in sheep. Anim. Sci. J, 73, 471-478.
11. 11. Shintani M., Ogawa Y., Ebihara K., Aizawa-Abe M., Miyanaga F., Takaya K., Hayash, T., Inoue G., Hosod K., Kojima M., Kangawa K., Nakao K., 2001. Ghrelin, an endogenous growth hormone secretagogue, is a novel orexigenic peptide that antagonizes leptin action through the activation of hypothalamic neuropeptide Y/Y1 receptor pathway. Diabetes, 50, 227–232.
12. 12. Cummings DE., Foster KE., 2003 Ghrelin-leptin Tango in body-weight regulation. Gastroenterology, 124, 1532-1535.
13. 13. Ukkola O., 2003. Ghrelin and insulin metabolism. European Journal of Clinical Investigation, 33, 183-185.
14. 14. Bauman DE., Currie WB., 1980. Partitioning of nutrients during pregnancy and lactation: a review of mechanisms involving homeostasis and homeorhesis. Journal of Dairy Science, 63, 1514-1529.
15. 15. Bell AW., 1995. Regulation of organic nutrient metabolism during transition from late pregnancy to early lactation. Journal of Animal Science, 73, 2804-2819.
16. 16. Barber MC, Clegg RA, Travers MT, Vernon R.G., 1997. Lipid metabolism in the lactating mammary gland. Biochimica et Biophysica Acta, 1347, 101-126.
17. 17. Van Haasteren GA., Van Toor H., Klootwijik W., Handler B., Linkels E., Van der Schoot P., 1996.Studies on the role of TRH and corticosterone in the regulation of prolactin and thyrotrophin secretion during lactation. J Endocrinol, 148, 325-336.
18. 18. Ota K., Yokoyama A., 1967. Body weight and food consumption of lactating rats: effects of ovariectomy and of arrest and resumption of suckling. J Endocrinol, 38, 251-61.
19. 19. Shibata K., Hosoda H., Kojima M., Kangawa K., Makino Y., Makino I., Kawarabayashi T., Futagami K., Gomita Y., 2004. Regulation of ghrelin secretion during pregnancy and lactation in the rat: possible involvement of hypothalamus. Peptides 25, 279-287.
20. 20. Kojima M., Kangawa K., 2005. Ghrelin: structure and function. Physiological Reviews, 85, 495-522.
21. 21. Vasilatos R., Wangsness PJ., 1981. Diurnal Variations in Plasma Insulin and Growth Hormone Associated with Two Stages of Lactation in High Producing Dairy Cows. Endocrinology, 108, 300-304.
22. 22. Kawai M., Yamaguchi M., Murakami T., Shima K., Murata Y., Kishi, K., 1997. The placenta is not the main source of leptin production in pregnant rat: gestational profile of leptin in plasma and adipose tissues. Biochemical and Biophysical Research Communications, 240, 798–802.
23. 23. Brogan RS., Mitchell SE., Trayhurn P., Smith MS., 1999. Suppression of leptin during lactation: ontribution of the suckling stimulus versus milk production. Endocrinology, 40, 2621-2627.
24. 24. Woodside B., Abizaid A., Walker C., 2000. Changes in leptin levels during lactation: implications for lactational hyperphagia and anovulation. Hormones and Behavior, 37, 353-365.
25. 25. Block SS., Butler WR., Ehrhardt RA., 2001. Decreased concentration of plasma leptin in periparturient dairy cows is caused by negative energy balance. Journal of Endocrinology, 171, 339–348.
26. 26. Aydin S., Ozkan Y., Erman F., Gurates B., Kilic N., Colak R., Gundoga, T., Catak Z., Bozkurt M., Akin O., Sen Y., Sahn I., 2008. Presence of obestatin in breast milk: Relationship among obestatin, ghrelin, and leptin in lactating women. Nutrition, 24, 689-693.