Demura R, Tajima S, Suzuki T, Yajima R, Odagiri E, Suda T, Tozawa F, Demura H, Kato H, Uchiyama T
Department of Internal Medicine, Tokyo Women's Medical College, Japan.
Endocr J. 1995 Feb;42(1):95-100. doi: 10.1507/endocrj.42.95.
Inhibin and activin are known to be involved in the pituitary hormone secretion as well as proliferation of the pituitary. We studied the expression of inhibin alpha, and beta A subunit and activin type II receptor (ACTR 2) mRNAs in human pituitary adenomas to determine the significance of inhibin and activin in pituitary hormone secretion. Tumor tissues were homogenized immediately after resection in guanidinium thiocyanate to extract total RNA. PCR was performed with reversely transcripted cDNA and respective amplification primers. DNA bands obtained for inhibin alpha, beta A and ACTR 2 by agarose gel-electrophoresis were 367, 285, and 389 bp, respectively. Messenger RNAs for inhibin beta A were demonstrated in all of the pituitary tissues studied, namely in 3 GH, 2 ACTH, 6 PRL and 1 FSH producing adenomas and 17 non-functioning adenomas. Inhibin alpha mRNAs were detected in 10 of 12 functioning adenomas and 15 of 17 non-functioning adenomas. ACTR 2 mRNAs were found in 11 out of 17 non-functioning adenomas, but only found in 3 out of 12 functioning adenomas. These results suggested local production of activin, a homodimer of beta-subunits, and inhibin, a heterodimer of alpha and beta subunits, in most of the pituitary adenomas regardless of their hormone secretion. On the other hand, a significantly higher incidence of ACTR 2 in non-functioning adenomas than in functioning adenomas suggested that activin had its main site of action in non-functioning adenomas, which could be potential gonadotropinomas.
已知抑制素和激活素参与垂体激素分泌以及垂体的增殖。我们研究了抑制素α、βA亚基和激活素II型受体（ACTR 2）mRNA在人垂体腺瘤中的表达，以确定抑制素和激活素在垂体激素分泌中的意义。肿瘤组织在切除后立即在硫氰酸胍中匀浆以提取总RNA。用逆转录的cDNA和各自的扩增引物进行PCR。通过琼脂糖凝胶电泳获得的抑制素α、βA和ACTR 2的DNA条带分别为367、285和389 bp。在所研究的所有垂体组织中均检测到抑制素βA的信使RNA，即在3例生长激素（GH）腺瘤、2例促肾上腺皮质激素（ACTH）腺瘤、6例催乳素（PRL）腺瘤、1例促卵泡激素（FSH）腺瘤和17例无功能腺瘤中。在12例功能性腺瘤中的10例以及17例无功能腺瘤中的15例中检测到抑制素α mRNA。在17例无功能腺瘤中的11例中发现了ACTR 2 mRNA，但在12例功能性腺瘤中仅在3例中发现。这些结果表明，在大多数垂体腺瘤中，无论其激素分泌情况如何，均可局部产生激活素（β亚基的同二聚体）和抑制素（α和β亚基的异二聚体）。另一方面，无功能腺瘤中ACTR 2的发生率显著高于功能性腺瘤，这表明激活素在无功能腺瘤中具有主要作用位点，而无功能腺瘤可能是潜在的促性腺激素瘤。
