Ray K P, Wallis M
Mol Cell Endocrinol. 1982 Nov-Dec;28(3):691-703. doi: 10.1016/0303-7207(82)90156-3.
The involvement of calcium in the regulation of prolactin secretion and a possible inhibitory mechanism of action for dopamine have been investigated. Basal prolactin secretion from cultured ovine pituitary cells was dependent on the concentration of calcium ions (Ca2+) in the medium and was inhibited by the presence of verapamil (10 microM). The divalent cation ionophore A23187 (1 microM) caused a rapid stimulation of prolactin release from the cells. The effect was essentially complete within 10 min and subsequently secretion of prolactin occurred at close to the basal rate. A23187 had no effect on cell cyclic AMP levels. Dopamine (0.1 microM) but not verapamil (10 microM) inhibited the A23187 (10 microM) induced release of prolactin. Inhibition of basal and A23187 (1 microM) stimulated prolactin secretion occurred over a similar range of dopamine concentrations. The dopamine receptor antagonist haloperidol (1 microM) reversed the inhibitory effect of dopamine (0.1 microM) on A23187-stimulated prolactin release. These results provide evidence to support the concept that control of Ca2+ handling by lactotrophs may be of fundamental importance in the regulation of prolactin secretion.
对钙参与催乳素分泌调节以及多巴胺可能的抑制作用机制进行了研究。培养的绵羊垂体细胞的基础催乳素分泌依赖于培养基中钙离子（Ca2+）的浓度，并受到维拉帕米（10微摩尔）的抑制。二价阳离子载体A23187（1微摩尔）可迅速刺激细胞释放催乳素。该效应在10分钟内基本完成，随后催乳素分泌接近基础速率。A23187对细胞环磷酸腺苷水平无影响。多巴胺（0.1微摩尔）而非维拉帕米（10微摩尔）抑制A23187（10微摩尔）诱导的催乳素释放。在相似的多巴胺浓度范围内，基础和A23187（1微摩尔）刺激的催乳素分泌均受到抑制。多巴胺受体拮抗剂氟哌啶醇（1微摩尔）可逆转多巴胺（0.1微摩尔）对A23187刺激的催乳素释放的抑制作用。这些结果提供了证据支持以下概念，即催乳细胞对Ca2+处理的控制在催乳素分泌调节中可能至关重要。
