Ontogeny of pulsatile secretion of gonadotropin-releasing hormone in the bull calf during infantile and pubertal development.
Ontogeny of pulsatile secretion of gonadotropin-releasing hormone in the bull calf during infantile and pubertal development.
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DOI：
10.1210/endo-124-1-248
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发表时间：
1989
期刊：
影响因子：
4.8
通讯作者：
R. E. Rodríguez;M. Wise
中科院分区：
文献类型：
--
作者：
R. E. Rodríguez;M. Wise
在公牛犊发育的婴儿期（出生至6周龄），几乎不存在LH的间歇性分泌。从婴儿期到青春期前（6-10周龄）的过渡期的特征是发作性LH释放。本研究的目的是描述这些发育阶段中GnRH间歇性释放的个体发育特征。在初步实验期间，对2、5、8和12周龄的小牛（n = 4/年龄）通过手术安装插管，以采集垂体门静脉和海绵窦混合血液。垂体门静脉和海绵窦和颈静脉血样收集了9至12小时的时间间隔为10分钟。在2周龄或5周龄小牛中未观察到LH脉冲。在8周龄和12周龄时，脉冲式LH释放变得明显，平均值分别为1.0 +/- 0.3和2.20 +/- 0.7脉冲/10 h。与LH分泌不同，2周龄和5周龄小牛均以脉冲方式释放GnRH（分别为3.5 +/- 0.2和5.0 +/- 0.6脉冲/10 h）。脉冲式GnRH释放的频率从8周龄时的7.9 +/- 0.4脉冲/10 h增加到12周龄时的8.9 +/- 0.7脉冲/10 h。这些发现表明在婴儿发育期间存在GnRH的脉冲式分泌。此外，在这个物种的脉冲式LH释放的出生后个体发育与脉冲式GnRH分泌的频率增加。
During the infantile period of development in the bull calf (birth to 6 weeks of age), there is a virtual absence of episodic secretion of LH. Transition from infancy to the prepubertal period (6-10 weeks of age) is characterized by the onset of episodic LH release. This study was conducted to characterize the ontogeny of episodic GnRH release during these developmental periods. During the primary experiment, calves at 2, 5, 8, and 12 weeks of age (n = 4/age) were surgically fitted with cannulae for the collection of mixed hypophyseal portal and cavernous sinus blood. Hypophyseal portal and cavernous sinus and jugular blood samples were collected over a 9- to 12-h period at 10 min intervals. No pulses of LH were observed in calves at 2 or 5 weeks of age. At 8 and 12 weeks of age, pulsatile LH release became evident with a mean of 1.0 +/- 0.3 and 2.20 +/- 0.7 pulses/10 h, respectively. Unlike LH secretion, calves at both 2 and 5 weeks of age released GnRH in a pulsatile manner (3.5 +/- 0.2 and 5.0 +/- 0.6 pulses/10 h, respectively). The frequency of pulsatile GnRH release increased from 7.9 +/- 0.4 pulses/10 h at 8 weeks of age to 8.9 +/- 0.7 pulses/10 h at 12 weeks of age. These findings demonstrate the presence of pulsatile secretion of GnRH during the infantile period of development. Furthermore, the postnatal ontogeny of pulsatile LH release in this species is associated with an increase in the frequency of pulsatile GnRH secretion.