Ray J, Okamura H, Kelly P A, Liebhaber S A, Cooke N E
Department of Human Genetics, University of Pennsylvania, Philadelphia 19104-6145.
Mol Endocrinol. 1990 Jan;4(1):101-7. doi: 10.1210/mend-4-1-101.
The biological activities of the GH-PRL family of hormones are mediated by selective binding to two classes of cell membrane receptors, somatogen and lactogen. Primate GH such as human GH (hGH) are unusual in that they bind to both classes of receptors. Replacement of exons 3 or 4 of the hGH gene by the corresponding exons of the rat PRL or rat GH genes results in the synthesis of chimeric proteins which retain the ability to bind to lactogen receptors but can no longer bind to somatogen receptors. This selective loss of somatogen receptor binding in the chimeric proteins suggests that certain of the structural determinants of somatogen and lactogen receptor binding activities in hGH are distinct and can be separately modified by a limited number of amino acid substitutions.
生长激素-催乳素家族激素的生物学活性是通过与两类细胞膜受体（生长激素受体和催乳素受体）的选择性结合来介导的。灵长类动物的生长激素，如人类生长激素（hGH），不同寻常之处在于它们能与这两类受体结合。用大鼠催乳素基因或大鼠生长激素基因的相应外显子替换hGH基因的外显子3或4，会导致嵌合蛋白的合成，这些嵌合蛋白保留了与催乳素受体结合的能力，但不再能与生长激素受体结合。嵌合蛋白中生长激素受体结合活性的这种选择性丧失表明，hGH中生长激素受体和催乳素受体结合活性的某些结构决定因素是不同的，并且可以通过有限数量的氨基酸替换分别进行修饰。
