Presence of an adenylate cyclase dually regulated by somatostatin and human pancreatic growth hormone (GH)-releasing factor in GH-secreting cells.
Presence of an adenylate cyclase dually regulated by somatostatin and human pancreatic growth hormone (GH)-releasing factor in GH-secreting cells.
复制标题
GH 分泌细胞中存在受生长抑素和人胰腺生长激素 (GH) 释放因子双重调节的腺苷酸环化酶。
作者：
Anna Spada;L. Vallar;Giuliana Giannattasio
我们研究了 SRIF 和人胰腺 GH 释放因子 44 (hpGRF-44) 对雄性大鼠垂体前叶（其中存在大量生长激素细胞）和人 GH 分泌垂体腺瘤（几乎均由生长激素细胞构成）腺苷酸环化酶 (AC) 活性的影响。腺瘤对两种药物在分泌方面的反应先前已在体外实验中得到证实。 SRIF 以剂量依赖性方式抑制肿瘤单层培养物中 GH 的释放。在最大有效浓度(10(-6)M)下抑制范围为32-66%。 hpGRF-44 以剂量依赖性方式刺激 GH 释放。 10(-7) M 时的刺激率为 78-172%。SRIF 和 hpGRF-44 显着影响两个系统中的 AC 活性。 SRIF 以剂量依赖性方式引起酶活性的显着抑制。在最大有效浓度(10(-5)M SRIF)下，对大鼠的抑制约为40％，对腺瘤的抑制范围为16-49％。抑制作用是GTP依赖性的。 hpGRF-44 显着刺激 AC 活性。刺激是剂量依赖性和GTP依赖性的。在最大有效浓度(10(-6)M)下，对大鼠的刺激约为650％，对腺瘤的刺激约为26-350％。这些结果表明 GH 分泌细胞中存在双重调节的 AC（受 SRIF 和 hpGRF-44）； cAMP 参与细胞内机制，在生长激素细胞中转导 SRIF 和 hpGRF-44 信号。
We have investigated the effects of SRIF and human pancreatic GH-releasing factor-44 (hpGRF-44) on adenylate cyclase (AC) activity of male rat anterior pituitaries (in which somatotrophs are present in large proportion) and of human GH-secreting pituitary adenomas (which are almost homogeneously constituted by somatotrophs). The adenoma's responsiveness to both agents in terms of secretion was previously demonstrated in in vitro experiments. SRIF inhibited in a dose-dependent fashion the GH release from monolayer cultures of the tumors. The inhibition ranged from 32-66% at the maximal effective concentration (10(-6) M). hpGRF-44 stimulated GH release in a dose-dependent fashion. The stimulation was 78-172% at 10(-7) M. SRIF and hpGRF-44 markedly affected AC activity in both systems. SRIF elicited a pronounced inhibition of the enzyme activity in a dose-dependent manner. The inhibition was about 40% in the rat and ranged from 16-49% in adenomas at the maximal effective concentration (10(-5) M SRIF). The inhibitory effect was GTP-dependent. hpGRF-44 markedly stimulated AC activity. The stimulation was dose dependent and GTP dependent. The stimulation was about 650% in the rat and 26-350% in adenomas at the maximal effective concentration (10(-6) M). These results suggest the presence of a dually regulated (by SRIF and hpGRF-44) AC in GH-secreting cells; an involvement of cAMP in the intracellular mechanisms transducing the signals of SRIF and hpGRF-44 in somatotrophs.
影响因子：
56.9
作者：
GUILLEMIN, R;BRAZEAU, P;WEHRENBERG, WB
通讯作者：
WEHRENBERG, WB
生长激素释放因子生长分泌素在体外释放垂体生长激素。
DOI：
10.1073/pnas.79.24.7909
发表时间：
1982
影响因子：
11.1
作者：
Brazeau,P;Ling,N;Böhlen,P;Esch,F;Ying,SY;Guillemin,R
通讯作者：
Guillemin,R
系统中激素结合和生物反应曲线的强制性分离取决于激素作用的次要介质。
DOI：
10.1073/pnas.78.3.1366
发表时间：
1981
影响因子：
11.1
作者：
Strickland,S;Loeb,JN
通讯作者：
Loeb,JN