Folkesson H G, Hedin L, Weström B R
Department of Animal Physiology, University of Lund, Sweden.
J Endocrinol. 1992 Aug;134(2):197-203. doi: 10.1677/joe.0.1340197.
The passage from the lower respiratory tract into the blood of human GH (hGH; M(r) = 22,000) and bovine serum albumin (BSA; M(r) = 67,000) was assessed after intratracheal instillation in adult rats. The plasma level of immunoreactive hGH reached its maximum at 0.5-1 h after instillation and had almost disappeared within 24 h. Higher plasma levels were obtained in male rats than in female rats resulting in a higher total lung passage of hGH in male rats than in female rats (means +/- S.D.; 6.0 +/- 1.7% vs 3.3 +/-1.2%, P<0.01). The plasma level of BSA showed a different pattern, with a maximum at 16-24 h after instillation and a total lung passage of 4.3 +/- 1.7% of the given dose for both sexes. The plasma levels of hGH increased nonlinearly with increasing dose instilled in the dose range 36-720 micrograms/kg body weight. When hGH was instilled daily at a dose of 720 micrograms/kg body weight to hypophysectomized rats for 1 week, they responded with a significant increase in body weight when compared with hypophysectomized control rats (16.8 +/- 4.2 g vs -1.8 +/- 2.4 g, P<0.001). The results demonstrate that, despite their different molecular weights, hGH and BSA pass through the lower respiratory tract into the circulation with similar efficiencies in the rat. However, the lung passage of hGH, unlike that of BSA, showed sexual dependency, an earlier plasma concentration maximum and a tendency of the passage to saturation with increasing dose instilled.(ABSTRACT TRUNCATED AT 250 WORDS)
在成年大鼠气管内滴注后，评估了人生长激素（hGH；相对分子质量M(r)=22,000）和牛血清白蛋白（BSA；相对分子质量M(r)=67,000）从下呼吸道进入血液的情况。免疫反应性hGH的血浆水平在滴注后0.5 - 1小时达到峰值，并在24小时内几乎消失。雄性大鼠的血浆水平高于雌性大鼠，导致雄性大鼠中hGH的总肺吸收量高于雌性大鼠（平均值±标准差；6.0±1.7%对3.3±1.2%，P<0.01）。BSA的血浆水平呈现不同模式，在滴注后16 - 24小时达到峰值，两性的总肺吸收量均为给予剂量的4.3±1.7%。在36 - 720微克/千克体重的剂量范围内，hGH的血浆水平随滴注剂量的增加而非线性增加。当以720微克/千克体重的剂量每天给垂体切除的大鼠滴注hGH，持续1周时，与垂体切除的对照大鼠相比，它们的体重显著增加（16.8±4.2克对 - 1.8±2.4克，P<0.001）。结果表明，尽管hGH和BSA分子量不同，但它们在大鼠中以相似的效率从下呼吸道进入循环。然而，与BSA不同，hGH的肺吸收表现出性别依赖性、更早的血浆浓度峰值以及随着滴注剂量增加而出现吸收饱和的趋势。（摘要截断于250字）
