Pregnancy stage and number of fetuses may influence maternal plasma leptin in ewes
2006
Kulcsár, Margit | Dankó, Gabriella | Magdy, H. G. I. | Reiczigel, J. | Forgach, T. | Proháczik, Angella | Delavaud, Carole | Magyar, K. | Chilliard, Y. | Solti, L. | Huszenicza, Gy
Maternal plasma leptin is elevated in ewes during pregnancy. The authors studied whether there was any relation between maternal plasma leptin and insulin concentrations, the number of fetuses and the circulating and faecal levels of gestagens. At the end of the breeding season in January the ovarian activity of Prolific Merino ewes was induced/synchronised with gestagen + eCG treatment. Ewes were inseminated artificially (AI) by laparoscopy. Blood and faecal samples were collected before AI (day 0) and again 41, 81 and 101 days later. The plasma levels of leptin (pL), insulin and progesterone (pP₄), and the faecal P₄ metabolite (P₄-met) content were determined. The day 0 level of pL was significantly higher in pregnant (n = 24) than in non-pregnant ewes (n = 32). By day 41 the pL of pregnant animals had doubled, it showed a further moderate increase on day 81, and decreased slightly thereafter. During pregnancy pP₄ and faecal P₄-met rose continuously and were positively correlated at all stages. The mean levels of pL and pP₄ and the faecal content of P₄-met were lower in ewes bearing single (n = 12) than in those with 2 (n = 6) or 3-5 fetuses (n = 6). Analysis of variance demonstrated significant differences according to the number of fetuses in the pL and pP₄, but not in P4-met (p = 0.042, 0.044, and 0.051, respectively). Leptin showed positive correlation with insulin before the AI but not during pregnancy. On days 41 and 81 pL showed a slight positive correlation with P₄ and P₄-met, which decreased slightly by day 101. This study shows that although leptinaemia is affected by the number of fetuses and the level of P₄, pregnancy stage is a more important regulator than these additional factors.
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