Bhaumick B, Bala R M
Biochem Biophys Res Commun. 1984 Jul 31;122(2):583-92. doi: 10.1016/s0006-291x(84)80073-x.
Binding of basic somatomedin (B-SM) and effect on alpha-aminoisobutyrate (AIB) uptake was studied in explants of term human placenta. B-SM demonstrated specific binding to the cultured explants. The binding was weakly inhibited by insulin. No significant degradation of the hormone was observed during incubation. The affinity cross-linking of [125I]B-SM binding to the explant membrane revealed a binding subunit of Mr 140 K. Addition of B-SM to the serum free medium stimulated the placental explant AIB uptake in a dose dependent manner. The incubated media containing FBS had less SM activity than the pre-incubated medium. The serum free incubated media did not contain measurable SM activity. The above findings that placental explants bind and have biological response to B-SM but do not produce B-SM suggest that SM has an endocrine rather than a paracrine action on human placenta.
在足月人胎盘外植体中研究了碱性生长调节素（B-SM）的结合及其对α-氨基异丁酸（AIB）摄取的影响。B-SM显示出与培养的外植体有特异性结合。胰岛素对这种结合有微弱抑制作用。孵育期间未观察到该激素有明显降解。[125I]B-SM与外植体膜的亲和交联显示出一个分子量为140K的结合亚基。向无血清培养基中添加B-SM以剂量依赖方式刺激胎盘外植体对AIB的摄取。含有胎牛血清（FBS）的孵育培养基中的生长调节素（SM）活性低于预孵育培养基。无血清孵育培养基中未检测到可测量的SM活性。上述胎盘外植体对B-SM有结合并产生生物学反应但不产生B-SM的发现表明，生长调节素对人胎盘具有内分泌而非旁分泌作用。
