EFFECTS OF MELATONIN ON LONG-DAY RESPONSES IN SHORT-DAY HOUSED ADULT SIBERIAN HAMSTERS
EFFECTS OF MELATONIN ON LONG-DAY RESPONSES IN SHORT-DAY HOUSED ADULT SIBERIAN HAMSTERS
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DOI：
10.1152/ajpregu.1988.255.5.r823
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发表时间：
1988-11-01
影响因子：
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通讯作者：
GOLDMAN, BD
中科院分区：
文献类型：
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作者：
BARTNESS, TJ;GOLDMAN, BD
当短光周期退化的西伯利亚仓鼠暴露于延长的光周期时，睾丸生长被刺激，这一效应可能是由松果体通过减少其激素褪黑激素（MEL）分泌的峰值夜间持续时间而介导的（D. S.卡特和B。D. Goldman，Endocrinology 113：1268-1273，1983）。我们在短光周期退化的成年雄性西伯利亚仓鼠身上检测了MEL的这种刺激或“促性腺”作用，这些仓鼠被切除了松果体（PINX），每天定时皮下注射MEL（1或10 μ g/天）或盐水或2）MEL的输注，其为“长日样”（4小时，10或100 ng/天）、“短日样”（10小时，10 ng/天）或对照盐水输注（4小时/天）。光退化假PINX仓鼠在当时被转移到长日。处理5周后，注射1 μ g MEL的仓鼠和两组输注4小时MEL的仓鼠具有模拟长日暴露的假PINX组的刺激反应[即， 睾丸、身体和附睾白色脂肪组织（EPIWAT）重量、总体脂、EPIWAT脂蛋白脂肪酶活性以及血清催乳素和促卵泡激素水平增加]。在注射10 μ g MEL或盐水和输注10小时MEL或盐水的仓鼠中未观察到这些作用。因此，峰值夜间持续时间的血清MEL的MEL分泌曲线的关键参数，刺激各种光周期反应时，光退化仓鼠暴露于延长日照。
Testis growth is stimulated when short photoperiod-regressed Siberian hamsters are exposed to a lengthening photoperiod, an effect presumably mediated by the pineal gland through a decrease in the peak nocturnal duration of secretion of its hormone melatonin (MEL) (D. S. Carter and B. D. Goldman, Endocrinology 113: 1268-1273, 1983). We examined this stimulatory or "progonadal" effect of MEL in short photoperiod-regressed, adult male Siberian hamsters that were pinealectomized (PINX) and given timed daily subcutaneous 1) injections of MEL (1 or 10 .mu.g/day) or saline or 2) infusions of MEL that were "long day-like" (4 h, 10 or 100 ng/day), "short day-like" (10 h, 10 ng/day), or control saline infusions (4 h/day). Photoregressed sham PINX hamsters were transferred to long days at the time. After 5 wk of treatment, 1-.mu.g MEL-injected hamsters and both groups of 4-h MEL-infused hamsters had stimulatory responses that mimicked those of the long-day-exposed, sham PINX group [i.e., increased testes, body, and epididymal white adipose tissue (EPIWAT) weights, total body fat, EPIWAT lipoprotein lipase activity, and serum prolactin and follicle-stimulating hormone levels]. These effects were not observed in 10-.mu.g MEL- or saline-injected and 10-h MEL- or saline-infused hamsters. Thus the peak nocturnal duration of serum MEL is the critical parameter of the MEL secretion profile for stimulating a variety of photoperiodic responses when photoregressed hamsters are exposed to lengthening daylengths.