Department of Zoology, Banaras Hindu University, Varanasi 221 005, UP, India.
Zoology (Jena). 2009;112(6):461-70. doi: 10.1016/j.zool.2009.03.002. Epub 2009 Sep 17.
The temporal phase relation of circadian oscillations is reported to regulate reproduction in many seasonally breeding avian and mammalian species, but its role in the reproductive regulation of continuous breeders is not yet known. Hence in the present study, six experimental groups of 3-week-old male Parkes strain mice, Mus musculus, were injected with 5-hydroxytryptophan (5-HTP, serotonin precursor) and L-dihydroxyphenylalanine (L-DOPA, dopamine precursor) at intervals of 0, 4, 8, 12, 16 or 20 hr (5mg/100g body weight per day for 13 days). Control mice received two daily injections of normal saline. When observed 24 days post-treatment, 8-hr mice exhibited low body weight and suppression of gonadal activity (spermatogenesis, sperm count/motility/viability and plasma testosterone concentration), while body weight and degree of gonadal development were higher in the 12-hr mice as compared to the controls. It is concluded that normal somatic and gonadal growth of pre-puberal mice may be suppressed with an 8-hr phase relation of circadian serotonergic and dopaminergic oscillations. On the other hand, a 12-hr phase relation accelerated the rate of gonadal maturation, while other relations led to more or less similar gonadal development as in the control mice. This study suggests the importance of circadian organization as a function of specific temporal phase relations of neural oscillations in the maturation of gonads. Although the exact mechanism still needs to be investigated, this seems to be mediated via effects on the neuroendocrine axis.
昼夜节律振荡的时相关系被报道可调节许多季节性繁殖的鸟类和哺乳动物物种的繁殖，但它在连续繁殖者的生殖调节中的作用尚不清楚。因此，在本研究中，将 6 组 3 周龄雄性 Parkes 品系小鼠（Mus musculus）每隔 0、4、8、12、16 或 20 小时注射 5-羟色氨酸（5-HTP，血清素前体）和 L-二羟苯丙氨酸（L-DOPA，多巴胺前体），每天 5mg/100g 体重，共 13 天。对照组小鼠接受两次生理盐水注射。治疗后 24 天观察时，8 小时组小鼠体重较低，性腺活动（精子发生、精子计数/活力/活力和血浆睾酮浓度）受到抑制，而 12 小时组小鼠的体重和性腺发育程度高于对照组。结论是，青春期前小鼠的正常体组织和性腺生长可能会因昼夜血清素能和多巴胺能振荡的 8 小时时相关系而受到抑制。另一方面，12 小时的时相关系加速了性腺成熟的速度，而其他时相关系导致的性腺发育与对照组相似或相似。这项研究表明了昼夜节律组织作为神经振荡特定时间相位关系在性腺成熟中的功能的重要性。尽管确切的机制仍需要研究，但这似乎是通过对神经内分泌轴的影响来介导的。
