Oberbauer A M, Murray J D
Department of Animal Science, University of California, Davis, CA 95616, USA.
Growth Dev Aging. 1998 Autumn;62(3):87-93.
Male and female transgenic mice carrying the regulatable ovine metallothionein-ovine growth hormone (oMt1a-oGH) transgene were exogenously induced to express elevated GH at maturity. Male transgenics responded to continuously elevated GH with smaller white adipose tissue depots (WAT); cessation of transgene stimulation with restoration of basal circulating GH ablated the improvement in WAT. Transgenic males in which the transgene was never exogenously activated expressed low levels of oGH (60.2 ng/ml) and this low, chronic level resulted in 30-50% larger (p < 0.05) gonadal, inguinal, and mesenteric WAT relative to all wildtype controls, transgenics actively expressing the transgene, or transgenics exposed to elevated GH for a limited time. Mature females continued to accrue body mass proportional to circulating GH. Similar to that observed in the males, transgenic females in which the transgene was never exogenously activated exhibited enlarged WAT that were 20-40% larger than the same depots in wildtype control females. However, in contrast to the data for the males, transgenic females that had experienced a four week exposure to elevated GH followed by a return to basal conditions tended to have the greatest WAT depots (p < 0.10). This would indicate that female adipocytes are still capable of responding to elevated GH with proliferation/differentiation at maturity. These data support the hypothesis that the generalized sexual dimorphic pattern of lipid deposition may be attributed to the sexually dimorphic pattern of GH experienced by the two sexes.
携带可调控的绵羊金属硫蛋白 - 绵羊生长激素（oMt1a - oGH）转基因的雄性和雌性小鼠在成熟时被外源诱导表达升高的生长激素（GH）。雄性转基因小鼠对持续升高的GH反应是白色脂肪组织库（WAT）较小；停止转基因刺激并恢复基础循环GH后，WAT的改善消失。从未被外源激活转基因的雄性转基因小鼠表达低水平的oGH（60.2 ng/ml），这种低水平的慢性状态导致其性腺、腹股沟和肠系膜WAT比所有野生型对照、积极表达转基因的转基因小鼠或仅在有限时间内暴露于升高GH的转基因小鼠大30 - 50%（p < 0.05）。成熟雌性继续按循环GH比例增加体重。与雄性观察到的情况类似，从未被外源激活转基因的雌性转基因小鼠表现出WAT增大，比野生型对照雌性的相同脂肪库大20 - 40%。然而，与雄性数据相反，经历四周升高GH暴露后再恢复到基础状态的转基因雌性往往具有最大的WAT库（p < 0.10）。这表明成熟雌性脂肪细胞在成熟时仍能够通过增殖/分化对升高的GH作出反应。这些数据支持这样的假设，即脂质沉积的普遍性别二态模式可能归因于两性所经历的GH的性别二态模式。
