Herington A C, Phillips L S, Daughaday W H
Acta Endocrinol (Copenh). 1976 Oct;83(2):259-68. doi: 10.1530/acta.0.0830259.
In these studies of the stimulation of embryonic chick pelvic rudiments by somatomedin (Sm) in serum, we have found that cartilage weight and duration of cartilage exposure to serum determine the stimulation of cartilage by serum and the relative stimulation by Sm and by other non-Sm serum components, respectively. These factors are critical for the use of this system to measure Sm in serum. Initial experiments revealed that incorporation of sulfate (SO4) by cartilage incubated in buffer fell rapidly after 9 h and reached very low levels by 30 h. Incubation in 40% normal human serum (NHS) produced significant stimulation of incorporation of SO4 after 4 h, and maintained at least initial levels of incorporation for 24 h. The greatest % stimulation by NHS over buffer was seen with prolonged incubation (44 h). However, specificity for Sm (iscrimination between NHS and hypophysectomized human serum (HHS)) was greater with shorter incubation times. The potency of HHS was 11, 42 and 92% of the potency of NHS following early, intermediate and late measurement of incorporation of SO4 by cartilage, respectively. The best overall results were obtained with intermediate incubation time and measurement of SO4 incorporation ((35S)-SO4 present for the final 5 h of a 25 h incubation), which allowed good precision (gamma = 0.17) while maintaining satisfactory specificity for Sm. Since prolonged incubation with late measurement of SO4 incorporation allowed the greatest % stimulation by serum with little differentiation between NHS and HHS, stimulation of incorporation of SO4 under these conditions is apparently due to non-Sm factors present in both NHS and HHS. In addition to incubation time, cartilage stimulation by serum was also determined by cartilage weight. Lighter cartilage (from younger embryos) was associated with higher unstimulated incorporation of SO4 (P less than 0.01), lower stimulation by added serum (P less than 0.01), and inadequate assay precision (P less than 0.05): satisfactory assays were generally obtained with cartilage rudiments weighing more than 0.7 mg (dry weight).
在这些关于血清中生长调节素（Sm）对鸡胚骨盆原基刺激作用的研究中，我们发现软骨重量以及软骨与血清接触的持续时间分别决定了血清对软骨的刺激作用，以及Sm和其他非Sm血清成分的相对刺激作用。这些因素对于利用该系统测量血清中的Sm至关重要。初步实验表明，在缓冲液中孵育的软骨对硫酸盐（SO4）的摄取在9小时后迅速下降，到30小时时降至非常低的水平。在40%正常人血清（NHS）中孵育4小时后，对SO4的摄取产生了显著刺激，并在24小时内至少维持初始摄取水平。长时间孵育（44小时）时，NHS对缓冲液的最大刺激百分比最为明显。然而，较短的孵育时间对Sm具有更高的特异性（区分NHS和垂体切除的人血清（HHS））。在软骨对SO4摄取的早期、中期和晚期测量中，HHS的效力分别为NHS效力的11%、42%和92%。在中期孵育时间并测量SO4摄取（在25小时孵育的最后5小时存在（35S）-SO4）时获得了最佳的总体结果，这在保持对Sm令人满意的特异性的同时具有良好的精密度（γ = 0.17）。由于长时间孵育并在后期测量SO4摄取时血清的最大刺激百分比最高，而NHS和HHS之间几乎没有差异，因此在这些条件下对SO4摄取的刺激显然是由于NHS和HHS中存在的非Sm因素。除了孵育时间外，血清对软骨的刺激作用还取决于软骨重量。较轻的软骨（来自较年轻的胚胎）与较高的未刺激SO4摄取（P < 0.01）、添加血清后的较低刺激（P < 0.01）以及不足的测定精密度（P < 0.05）相关：通常使用重量超过0.7毫克（干重）的软骨原基可获得满意的测定结果。
