Ching M, Trakulrungsi C, Somana R, Evans A B, Evans E S
Acta Endocrinol (Copenh). 1977 May;85(1):25-38. doi: 10.1530/acta.0.0850025.
The claim has been made that thyrotrophin (TSH) can augment the action of growth hormone (GH) to stimulate growth of the epiphysial cartilage plate of the hypophysectomized rat's tibia. The TSH induces its effect via secretion of thyroid hormones which in turn enhance the stimulatory action of GH. If this is true then the employment of the tibia test, whose endpoint is the increase in thickness of the epiphysial cartilage plate in response to GH present either in crude pituitary extracts or relatively purified preparations, which also are likely to contain modest or appreciable quantities of TSH, requires further examination. The present study utilized various fractions of crude pituitary extracts from intact and thyroidectomized rats that respectively contained appreciable quantities of GH or essentially no GH. Fractional aliquots of pituitary extracts from thyroidectomized rats were administered concomitantly with graded doses of exogenous GH to hypophysectomized rats to determine the point at which TSH in the extracts was sufficiently able to stimulate significant tibial plate growth when compared to recipients given GH alone. Purified GH and TSH were also administered in various doses to hypophysectomized recipients in a further attempt to delineate the dose range at which TSH augments the action of GH to promote significant chondrogenesis of the epiphysial plate. The results indicate that the enhancement of the GH effect on the cartilage plate by TSH was evident only when quantities above 100 microng bovine GH were co-administered with 100 mU bovine TSH. As little as 40 mU TSH augmented the growth effect of 400 microng GH on the cartilage plate, demonstrating that smaller quantities of TSH could potentiate larger quantities of GH. These data, therefore, suggest that extracts equivalent to not more than one-half of a normal adult rat's anterior pituitary gland should be administered to hypophysectomized rats for bioassay of GH. Fractions of glands greater than this may contain sufficient amounts of TSH to augment the appreciable quantities of GH already present.
有人声称促甲状腺激素（TSH）可以增强生长激素（GH）的作用，以刺激垂体切除大鼠胫骨的骺软骨板生长。TSH通过分泌甲状腺激素来诱导其效应，而甲状腺激素反过来又增强了GH的刺激作用。如果这是真的，那么使用胫骨试验就需要进一步研究，该试验的终点是骺软骨板厚度的增加，以响应粗制垂体提取物或相对纯化制剂中存在的GH，而这些制剂也可能含有适量或大量的TSH。本研究使用了来自完整大鼠和甲状腺切除大鼠的粗制垂体提取物的各种组分，这些组分分别含有大量的GH或基本上不含GH。将甲状腺切除大鼠垂体提取物的分级等分试样与分级剂量的外源性GH同时给予垂体切除大鼠，以确定与单独给予GH的接受者相比，提取物中的TSH足以刺激胫骨板显著生长的点。还向垂体切除的接受者给予不同剂量的纯化GH和TSH，以进一步试图确定TSH增强GH作用以促进骺板显著软骨形成的剂量范围。结果表明，仅当超过100微克牛GH与100毫单位牛TSH共同给药时，TSH对软骨板的GH效应增强才明显。低至40毫单位TSH就增强了400微克GH对软骨板的生长效应，表明较少量的TSH可以增强较大量的GH。因此，这些数据表明，对于垂体切除大鼠进行GH生物测定时，应给予不超过正常成年大鼠垂体前叶一半的提取物。大于此量的腺体组分可能含有足够量的TSH，以增强已经存在的大量GH。
