Shibayama K, Ohyama Y, Ono M, Furudate S
Department of Pediatrics, Kitasato University School of Medicine, Kanagawa, Japan.
J Endocrinol. 1993 Aug;138(2):307-13. doi: 10.1677/joe.0.1380307.
The rdw rat (gene symbol: rdw) with hereditary dwarfism has been shown immunohistochemically to have subnormal numbers not only of GH- but also of prolactin- and thyrotrophin-positive cells. To characterize the dwarfism of this strain, the expression of pituitary hormone mRNAs was examined by Northern hybridization. The pituitary gland in the rdw rat expressed 30-100 times less GH and prolactin mRNAs than normal controls, whereas mRNAs for pro-opiomelanocortin and the alpha subunit of rat glycoprotein hormone revealed a significant increase. There was a non-significant difference in rat LH-beta subunit and FSH-beta subunit between normal and rdw rats. The suppressed expression of a pituitary-specific transcription factor, Pit-1, is considered to cause hereditary dwarfism in mouse strains Snell and Jackson, whose phenotypes resemble those of the rdw rat. In this study, however, no difference in mRNA expression for Pit-1 was found between rdw rats and controls. This work indicates that the rdw rat may not have the same genotype as the phenotypically similar dwarf mice, Snell, Jackson and Ames.
遗传性侏儒症的rdw大鼠（基因符号：rdw）经免疫组织化学研究发现，不仅生长激素（GH）阳性细胞数量低于正常水平，催乳素和促甲状腺激素阳性细胞数量也低于正常水平。为了明确该品系侏儒症的特征，通过Northern杂交检测了垂体激素mRNA的表达。rdw大鼠垂体中GH和催乳素mRNA的表达量比正常对照低30至100倍，而阿黑皮素原和大鼠糖蛋白激素α亚基的mRNA表达显著增加。正常大鼠和rdw大鼠之间，促黄体生成素β亚基（LH-β）和促卵泡生成素β亚基（FSH-β）的表达无显著差异。垂体特异性转录因子Pit-1表达受抑制被认为是导致Snell和Jackson小鼠品系遗传性侏儒症的原因，这两个品系的表型与rdw大鼠相似。然而在本研究中，未发现rdw大鼠与对照之间Pit-1的mRNA表达存在差异。这项研究表明，rdw大鼠可能与表型相似的侏儒小鼠Snell、Jackson和Ames具有不同的基因型。
