Jansson J O, Oscarsson J, Mode A, Ritzén E M
Department of Physiology, University of Göteborg, Sweden.
J Endocrinol. 1989 Sep;122(3):725-32. doi: 10.1677/joe.0.1220725.
The serum concentration of corticosteroid-binding globulin (CBG) is higher in female rats than in males. Combined hypophysectomy and gonadectomy of female rats reduced the serum concentration of CBG as measured by steady-state polyacrylamide gel electrophoresis, whereas hypophysectomy of male rats increased serum CBG. These effects were seen despite replacement therapy with thyroxine and glucocorticoids. Moreover, neither androgen nor oestrogen treatment affected the serum concentrations of CBG in hypophysectomized rats. Continuous infusions of human or bovine GH (1.4 U/kg per day), by means of osmotic minipumps for 1 week, increased serum concentrations of CBG in both hypophysectomized male and female rats. In contrast, intermittent GH replacement therapy by s.c. injections at 12-h intervals either had no effect or suppressed serum CBG levels. In male rats, neonatal (days 1-2) gonadectomy increased CBG levels more than did prepubertal (day 25) gonadectomy, and testosterone replacement therapy reversed these effects. It is concluded that GH increases the serum CBG levels of hypophysectomized rats when it is given in a continuous manner, but not when given intermittently. The sex difference in serum CBG levels of normal rats may, therefore, be attributed to the more continuous secretory pattern of GH previously observed in female rats.
雌性大鼠血清中皮质类固醇结合球蛋白（CBG）的浓度高于雄性大鼠。通过稳态聚丙烯酰胺凝胶电泳测定，雌性大鼠联合垂体切除和性腺切除可降低血清CBG浓度，而雄性大鼠垂体切除则增加血清CBG浓度。尽管给予甲状腺素和糖皮质激素替代治疗，仍可观察到这些效应。此外，雄激素或雌激素治疗均不影响垂体切除大鼠的血清CBG浓度。通过渗透微型泵持续输注人或牛生长激素（GH，每天1.4 U/kg）1周，可使垂体切除的雄性和雌性大鼠血清CBG浓度升高。相比之下，每12小时皮下注射进行间歇性GH替代治疗要么没有效果，要么会抑制血清CBG水平。在雄性大鼠中，新生期（第1 - 2天）性腺切除比青春期前（第25天）性腺切除更能增加CBG水平，而睾酮替代治疗可逆转这些效应。得出的结论是，持续给予GH可增加垂体切除大鼠的血清CBG水平，但间歇性给予则不然。因此，正常大鼠血清CBG水平的性别差异可能归因于先前在雌性大鼠中观察到的更持续的GH分泌模式。
