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.

Ghrelin, obestatin, and nesfatin-1 peptides are regarded as the primary regulators of the body’s appetite and energy balance. However, few studies have explored the roles of these peptides in milk and in metabolic adaptation in sheep. The presence of these peptides was investigated in blood samples from sheep and lambs and in milk samples from sheep during the early lactation phase in the current study. Thirty healthy ewes along with their single lambs were followed through their 3 ^rd to 5 ^th week after giving birth. Blood samples from ewes and lambs, and matched milk samples, were collected and analyzed by using enzyme-linked immunosorbent assay (ELISA) kits. Sampling was conducted over three weeks, and differences among time periods were compared. A significant increase was recorded for ghrelin and obestatin levels in plasma, whereas nesfatin-1 levels were decreased to a considerable extent. The milk samples followed a similar pattern with ghrelin and obestatin levels increased, whereas nesfatin-1 levels decreased. Nevertheless, a similar pattern was recorded for plasma samples. This study detected obestatin and nesfatin-1 peptides from the sheep milk for the first time. It is thought that coordinated action of these peptides affects the body, milking and offspring of sheep during early lactation phase. The increased ghrelin and obestatin levels along with decreased level of nesfatin-1 decreases work in coordination to fulfill energy needs of sheep. The detection of these peptides in milk samples warrants that energy balance of offsprings can be altered by maternal metabolism. This study provides first evidence for the presence of these peptides in the milk samples and confirms that these peptides can alter feeding behavior and energy regulation in lambs.

R-spondin 1 (RSPO1) and R-spondin 3 (RSPO3) contribute to reproductive development and feeding regulation, but their hypothalamic glutamatergic regulation remains unclear. We hypothesized that NMDA and non-NMDA receptor mechanisms contribute to hypothalamic RSPO neuronal activation. Given steroid-sensitive hypothalamic glutamatergic signaling, we compared activation and antagonist-mediated attenuation between sexes. Adult male and metestrous female Sprague–Dawley rats received kainic acid or AMPA with or without CNQX pretreatment, or NMDA with or without MK-801 pretreatment. RSPO/c-Fos labeling assessed activation in the supraoptic (SON), paraventricular (PVN), and arcuate (ARC) nuclei; ELISA assessed accompanying changes in serum RSPO concentrations. All agonists activated both populations in all nuclei. Only kainate-induced PVN RSPO3 activation differed between sexes (females, 89.3%; males, 72.8%; unadjusted p = 0.039), an isolated finding among 18 agonist comparisons. Antagonists attenuated all responses, although activation remained above control in 17 of 36 conditions. Females showed greater attenuation in selected kainate and NMDA conditions in the SON and PVN. Serum changes did not parallel neuronal activation. These findings support NMDA and non-NMDA receptor involvement and sex-dependent attenuation of RSPO neuronal activation. Given the central feeding effects of RSPOs, their sex-dependent glutamatergic regulation within neuroendocrine nuclei may contribute to sex differences in metabolic control.