Baumann G, Shaw M A, Merimee T J
Center for Endocrinology, Metabolism and Nutrition, Northwestern University Medical School, Chicago, IL.
N Engl J Med. 1989 Jun 29;320(26):1705-9. doi: 10.1056/NEJM198906293202601.
The cause of growth hormone resistance and short stature in African Pygmies in unknown. Low levels of insulin-like growth factor 1 that fail to respond to growth hormone suggest a possible deficiency of growth hormone receptors. The high-affinity growth hormone-binding protein is a fragment of the growth hormone receptor and may be an indicator of the number of receptors in tissues. We measured growth hormone-binding activity in plasma from 20 pygmies and 12 control subjects (7 white Americans and 5 non-Pygmy black Africans of normal stature). Growth hormone binding to the high-affinity binding protein was significantly reduced in the Pygmies as compared with the controls (mean +/- SD, 6.50 +/- 2.33 percent vs. 12.95 +/- 3.95 percent bound per 160 microliters of plasma; P less than 0.001); however, there was substantial overlap between the values for Pygmies and controls. Growth hormone binding to the low-affinity binding protein was similar in Pygmies and control subjects. We conclude that Pygmies have low levels of high-affinity growth hormone-binding protein in their plasma, which may indicate a reduced number of growth hormone receptors in their tissues. The finding may help explain the resistance to growth in Pygmies, but there may be additional reasons, related to the receptors or not, for their short stature.
非洲俾格米人生长激素抵抗和身材矮小的原因尚不清楚。低水平的胰岛素样生长因子1对生长激素无反应，提示可能存在生长激素受体缺乏。高亲和力生长激素结合蛋白是生长激素受体的一个片段，可能是组织中受体数量的一个指标。我们检测了20名俾格米人和12名对照者（7名美国白人和5名身材正常的非俾格米黑人）血浆中的生长激素结合活性。与对照组相比，俾格米人血浆中生长激素与高亲和力结合蛋白的结合显著降低（每160微升血浆中结合的平均±标准差，俾格米人为6.50±2.33%，对照组为12.95±3.95%；P<0.001）；然而，俾格米人和对照组的值有很大重叠。俾格米人和对照者血浆中生长激素与低亲和力结合蛋白的结合相似。我们得出结论，俾格米人血浆中高亲和力生长激素结合蛋白水平较低，这可能表明其组织中生长激素受体数量减少。这一发现可能有助于解释俾格米人对生长的抵抗，但他们身材矮小可能还有其他原因，与受体有关或无关。
