Cardoso Rodolfo C, Alves Bruna R C, Prezotto Ligia D, Thorson Jennifer F, Tedeschi Luis O, Keisler Duane H, Amstalden Marcel, Williams Gary L
Animal Reproduction LaboratoryTexas A&M AgriLife Research Station, 3507 Highway 59E, Beeville, Texas 78102, USADepartment of Animal ScienceKleberg Center, Texas A&M University, College Station, Texas 77843, USADivision of Animal SciencesAnimal Science Research Center, University of Missouri, Columbia, Missouri 65211, USA Animal Reproduction LaboratoryTexas A&M AgriLife Research Station, 3507 Highway 59E, Beeville, Texas 78102, USADepartment of Animal ScienceKleberg Center, Texas A&M University, College Station, Texas 77843, USADivision of Animal SciencesAnimal Science Research Center, University of Missouri, Columbia, Missouri 65211, USA.
Animal Reproduction LaboratoryTexas A&M AgriLife Research Station, 3507 Highway 59E, Beeville, Texas 78102, USADepartment of Animal ScienceKleberg Center, Texas A&M University, College Station, Texas 77843, USADivision of Animal SciencesAnimal Science Research Center, University of Missouri, Columbia, Missouri 65211, USA.
J Endocrinol. 2014 Dec;223(3):289-98. doi: 10.1530/JOE-14-0504. Epub 2014 Oct 17.
Feeding a high-concentrate diet to heifers during the juvenile period, resulting in increased body weight (BW) gain and adiposity, leads to early-onset puberty. In this study, we tested the hypothesis that the increase in GnRH/LH release during nutritional acceleration of puberty is accompanied by reciprocal changes in circulating leptin and central release of neuropeptide Y (NPY). The heifers were weaned at 3.5 months of age and fed to gain either 0.5 (Low-gain; LG) or 1.0 kg/day (High-gain; HG) for 30 weeks. A subgroup of heifers was fitted surgically with third ventricle guide cannulas and was subjected to intensive cerebrospinal fluid (CSF) and blood sampling at 8 and 9 months of age. Mean BW was greater in HG than in LG heifers at week 6 of the experiment and remained greater thereafter. Starting at 9 months of age, the percentage of pubertal HG heifers was greater than that of LG heifers, although a replicate effect was observed. During the 6-h period in which CSF and blood were collected simultaneously, all LH pulses coincided with or shortly followed a GnRH pulse. At 8 months of age, the frequency of LH pulses was greater in the HG than in the LG group. Beginning at 6 months of age, concentrations of leptin were greater in HG than in LG heifers. At 9 months of age, concentrations of NPY in the CSF were lesser in HG heifers. These observations indicate that increased BW gain during juvenile development accelerates puberty in heifers, coincident with reciprocal changes in circulating concentrations of leptin and hypothalamic NPY release.
在幼年期给小母牛饲喂高浓缩日粮，会导致体重（BW）增加和肥胖加剧，进而引发青春期提前。在本研究中，我们检验了以下假设：青春期营养加速期间促性腺激素释放激素（GnRH）/促黄体生成素（LH）释放增加的同时，循环中的瘦素和神经肽Y（NPY）的中枢释放会发生相应变化。小母牛在3.5月龄时断奶，并在30周内分别按每天增重0.5千克（低增重组；LG）或1.0千克（高增重组；HG）进行饲养。对一组小母牛进行手术植入第三脑室引导套管，并在8月龄和9月龄时进行密集的脑脊液（CSF）和血液采样。在实验第6周时，HG组小母牛的平均体重高于LG组，且此后一直保持较高水平。从9月龄开始，HG组青春期小母牛的比例高于LG组，不过观察到了重复效应。在同时采集CSF和血液的6小时期间，所有LH脉冲均与GnRH脉冲同时出现或紧随其后。在8月龄时，HG组LH脉冲频率高于LG组。从6月龄开始，HG组小母牛的瘦素浓度高于LG组。在9月龄时，HG组小母牛CSF中的NPY浓度较低。这些观察结果表明，幼年期体重增加加速会使小母牛青春期提前，同时伴随着循环中瘦素浓度和下丘脑NPY释放的相应变化。
