Castro M G, Gusovsky F, Loh Y P
Section on Cellular Neurobiology, Laboratory of Neurochemistry and Neuroimmunology, National Institute of Child Health and Human Development, Bethesda, MD 20892.
Mol Cell Endocrinol. 1989 Aug;65(1-2):165-73. doi: 10.1016/0303-7207(89)90177-9.
The effect of arginine vasopressin (AVP) and corticotropin releasing factor (CRF) an adrenocorticotropin (ACTH) secretion, phosphatidylinositol breakdown and cAMP accumulation was examined in primary cultures of mouse anterior pituitary cells. AVP and CRF added alone stimulated ACTH secretion in a dose-dependent manner. At 10(-8) M concentration of peptide, AVP and CRF stimulated ACTH secretion 2.8- and 4.6-fold, respectively. AVP and CRF added in combination at equal doses gave an additive effect. CRF enhanced cAMP accumulation, but AVP had no effect on basal or CRF-induced cAMP accumulation. Both forskolin (10(-5) M) and 8-bromo-cAMP (10(-3) M) increased ACTH secretion in these cells by 2.8- and 1.7-fold, respectively. AVP induced the breakdown of phosphoinositides, and CRF alone, or in combination with AVP did not modify this effect. Phorbol 12-myristate 13-acetate (10(-7) M), dioctanoylglycerol (10(-4) M) and phospholipase C (100 mU/ml) also stimulated ACTH secretion in these cells by 4.2-, 2.4-, and 3.7-fold, respectively. Depletion of intracellular and extracellular Ca2+ decreased ACTH secretion, but had no significant effect on CRF-induced cAMP accumulation. However, AVP-induced phosphoinositide breakdown was dependent on extracellular Ca2+. These results indicate that CRF stimulates ACTH secretion via the cAMP-dependent pathway and AVP via the phosphoinositide breakdown-phospholipase C pathway. In the presence of AVP and CRF, both pathways appear to operate independently to produce an additive effect on ACTH secretion.
在小鼠垂体前叶细胞原代培养物中，研究了精氨酸加压素（AVP）和促肾上腺皮质激素释放因子（CRF）对促肾上腺皮质激素（ACTH）分泌、磷脂酰肌醇分解及环磷酸腺苷（cAMP）积累的影响。单独添加AVP和CRF均以剂量依赖方式刺激ACTH分泌。在肽浓度为10⁻⁸M时，AVP和CRF分别刺激ACTH分泌2.8倍和4.6倍。等剂量联合添加AVP和CRF产生相加效应。CRF增强cAMP积累，但AVP对基础或CRF诱导的cAMP积累无影响。毛喉素（10⁻⁵M）和8-溴-cAMP（10⁻³M）分别使这些细胞中的ACTH分泌增加2.8倍和1.7倍。AVP诱导磷酸肌醇分解，单独的CRF或与AVP联合使用均不改变此效应。佛波酯（10⁻⁷M）、二辛酰甘油（10⁻⁴M）和磷脂酶C（100 mU/ml）也分别使这些细胞中的ACTH分泌增加4.2倍、2.4倍和3.7倍。细胞内和细胞外Ca²⁺耗竭降低ACTH分泌，但对CRF诱导的cAMP积累无显著影响。然而，AVP诱导的磷酸肌醇分解依赖于细胞外Ca²⁺。这些结果表明，CRF通过cAMP依赖性途径刺激ACTH分泌，而AVP通过磷酸肌醇分解-磷脂酶C途径刺激ACTH分泌。在存在AVP和CRF时，两条途径似乎独立发挥作用，对ACTH分泌产生相加效应。
