González-Parra S, Argente J, García-Segura L M, Chowen J A
Universidad Autónoma, Hospital Infantil del Niño Jesús, Madrid, España.
Neuroendocrinology. 1998 Sep;68(3):152-62. doi: 10.1159/000054361.
Growth hormone (GH) and prolactin (PRL) secretion differ significantly between adult males and females and this is due, at least in part, to the postpubertal hormone environment which affects GH and PRL gene expression, as well as somatotrope and lactotrope proliferation. However, the role of the neonatal steroid environment in this phenomenon is less well understood. We have used in situ hybridization to determine the number of GH and PRL mRNA containing cells, as well as the level of expression of these two hormones and of the pituitary transcription factor 1 (Pit-1). Neonatally castrated male rats that had been exposed to testosterone during the neonatal period, adulthood or during both periods, males castrated as adults, normal adult males and normal proestrous females were used. Orchidectomy of adult rats had no effect on the number of somatotropes or lactotropes, but significantly reduced GH and PRL mRNA levels. Neonatal castration significantly reduced the percentage of somatotropes and increased that of lactotropes in the adult male. In addition, GH and Pit-1 mRNA levels were reduced significantly, but PRL mRNA levels were not modified. Treatment of neonatally castrated males with testosterone during the neonatal period significantly increased the percentage of somatotropes and decreased the percentage of lactotropes compared to vehicle-treated animals. It also increased GH and Pit-1 mRNA levels, but did not affect PRL mRNA levels. Adult testosterone treatment significantly increased the percentage of both somatotropes and lactotropes, as well as GH, PRL and Pit-1 mRNA levels. Treatment of neonatally castrated males with testosterone during both the neonatal and adult periods returned the percentage of somatotropes and lactotropes, as well as GH, PRL and Pit-1 mRNA levels, to that of the intact male. These results suggest that, although the postpubertal steroid environment is important in determining anterior pituitary hormone synthesis and cellular composition, the neonatal steroid environment also plays an important role in this phenomenon.
成年男性和女性的生长激素（GH）和催乳素（PRL）分泌存在显著差异，这至少部分归因于青春期后的激素环境，该环境会影响GH和PRL基因表达以及生长激素细胞和催乳激素细胞的增殖。然而，新生儿期类固醇环境在这一现象中的作用尚不太清楚。我们使用原位杂交来确定含GH和PRL mRNA的细胞数量，以及这两种激素和垂体转录因子1（Pit-1）的表达水平。使用了在新生儿期、成年期或两个时期都暴露于睾酮的新生期阉割雄性大鼠、成年期阉割的雄性大鼠、正常成年雄性大鼠和正常动情前期雌性大鼠。成年大鼠去势对生长激素细胞或催乳激素细胞的数量没有影响，但显著降低了GH和PRL mRNA水平。新生期阉割显著降低了成年雄性中生长激素细胞的百分比，并增加了催乳激素细胞的百分比。此外，GH和Pit-1 mRNA水平显著降低，但PRL mRNA水平未改变。与载体处理的动物相比，在新生儿期用睾酮治疗新生期阉割的雄性大鼠，显著增加了生长激素细胞的百分比，降低了催乳激素细胞的百分比。它还增加了GH和Pit-1 mRNA水平，但不影响PRL mRNA水平。成年期睾酮治疗显著增加了生长激素细胞和催乳激素细胞的百分比，以及GH、PRL和Pit-1 mRNA水平。在新生儿期和成年期都用睾酮治疗新生期阉割的雄性大鼠，使生长激素细胞和催乳激素细胞的百分比以及GH、PRL和Pit-1 mRNA水平恢复到完整雄性的水平。这些结果表明，尽管青春期后的类固醇环境在决定垂体前叶激素合成和细胞组成方面很重要，但新生儿期类固醇环境在这一现象中也起着重要作用。
