Fukuda M, Miyamoto K, Hasegawa Y, Ibuki Y, Igarashi M
Mol Cell Endocrinol. 1987 May;51(1-2):41-50. doi: 10.1016/0303-7207(87)90117-1.
The effects of inhibin on gonadotropin secretion from cultured rat anterior pituitary cells were examined by using purified porcine follicular fluid (pFF) 32 kDa inhibin. pFF 32 kDa inhibin suppressed the basal FSH secretion as well as cell content of FSH with identical ED50 values (ED50 = 1.0 ng/ml) in a dose-dependent manner, but did not alter either basal secretion or cell content of LH. On the other hand, pretreatment of the pituitary cells with pFF 32 kDa inhibin during the first 3 days resulted in suppression of subsequent LH-RH-stimulated release of both FSH and LH in a dose-dependent manner, indicating that the suppression of LH-RH-stimulated release of LH is one of the intrinsic inhibin actions on pituitary cells. The marked difference between ED50 values for FSH (ED50 = 1.1 ng/ml) and LH (ED50 = 2.5 ng/ml) in the suppression of LH-RH-stimulated release of gonadotropins, together with the fact that the total amount of LH (cell content plus released) after LH-RH stimulation remained unchanged following inhibin treatment suggests that the suppression of LH-RH-stimulated release of LH by inhibin is quite different from that of FSH regarding the action mechanism. Similarly, cycloheximide, an inhibitor of protein biosynthesis, suppressed both basal secretion and cell content of FSH with almost the same ED50 values (ED50 = 22.5 ng/ml) but did not alter either basal secretion or cell content of LH. Cycloheximide also suppressed LH-RH-stimulated release of both FSH and LH, and the ED50 values were different from each other (ED50 = 25.0 ng/ml for FSH and 60.0 ng/ml for LH suppression, respectively). Our finding that cycloheximide completely mimicked the action of inhibin on gonadotropin secretion strongly suggests that LH is quite insensitive to biosynthetic inhibition, and that preferential effects of inhibin or cycloheximide on FSH in appearance may reflect the difference between LH and FSH in susceptibility to biosynthetic inhibition.
利用纯化的猪卵泡液（pFF）32 kDa抑制素，研究了抑制素对培养的大鼠垂体前叶细胞促性腺激素分泌的影响。pFF 32 kDa抑制素以剂量依赖性方式抑制基础FSH分泌以及FSH的细胞含量，二者的半数有效剂量（ED50）相同（ED50 = 1.0 ng/ml），但对LH的基础分泌和细胞含量均无影响。另一方面，在最初3天用pFF 32 kDa抑制素预处理垂体细胞，会导致随后LH-RH刺激的FSH和LH释放均呈剂量依赖性抑制，这表明抑制LH-RH刺激的LH释放是抑制素对垂体细胞的固有作用之一。在抑制LH-RH刺激的促性腺激素释放方面，FSH（ED50 = 1.1 ng/ml）和LH（ED50 = 2.5 ng/ml）的ED50值存在显著差异，此外，抑制素处理后，LH-RH刺激后LH的总量（细胞含量加上释放量）保持不变，这表明抑制素抑制LH-RH刺激的LH释放与FSH在作用机制上有很大不同。同样，蛋白质生物合成抑制剂放线菌酮以几乎相同的ED50值（ED50 = 22.5 ng/ml）抑制FSH的基础分泌和细胞含量，但对LH的基础分泌和细胞含量均无影响。放线菌酮也抑制LH-RH刺激的FSH和LH释放，且二者的ED50值彼此不同（FSH抑制的ED50 = 25.0 ng/ml，LH抑制的ED50 = 60.0 ng/ml）。我们发现放线菌酮完全模拟了抑制素对促性腺激素分泌的作用，这强烈表明LH对生物合成抑制相当不敏感，抑制素或放线菌酮在外观上对FSH的优先作用可能反映了LH和FSH在生物合成抑制敏感性上的差异。
