Van Bael A, Proesmans M, Tilemans D, Denef C
Department of Molecular Cell Biology, University of Leuven, School of Medicine, Belgium.
J Mol Endocrinol. 1995 Feb;14(1):91-100. doi: 10.1677/jme.0.0140091.
Addition of LHRH for 40 h to aggregate cell cultures of 14-day-old rat pituitary significantly decreased the number of [3H]thymidine ([3H]T)-incorporating cells which immunostained for GH protein as well as the number of [3H]T-labelled cells expressing GH mRNA detectable by in situ hybridization with a digoxigenin-labelled riboprobe. The effect at the level of GH protein was seen at a dose of 1 nM LHRH. However, the effect at the GH mRNA level required a higher dose of LHRH (10 nM) or a longer incubation time (64 h). Treatment of the cultures for 40 h with 0.1 nM GH-releasing factor (GRF) provoked a 54% increase in the number of [3H]T-labelled cells containing GH mRNA and a 30% increase in the number of cells immunostained for GH protein. The latter effects of GRF were completely blocked by simultaneous addition of LHRH (1 nM) to the cultures. In the absence of GRF, LHRH (1 nM) also had an inhibitory effect on the total number of cells containing GH mRNA and a comparable effect on the total number of cells stained for GH protein. The present data show that LHRH is capable of inhibiting the GRF-independent as well as the GRF-dependent development of somatotrophs in postnatal rat pituitary in culture.
向14日龄大鼠垂体的聚集细胞培养物中添加促黄体生成素释放激素（LHRH）40小时，显著减少了对生长激素（GH）蛋白进行免疫染色的[³H]胸腺嘧啶核苷（[³H]T）掺入细胞的数量，以及通过与地高辛标记的核糖探针进行原位杂交可检测到的表达GH mRNA的[³H]T标记细胞的数量。在1 nM LHRH的剂量下可观察到对GH蛋白水平的影响。然而，对GH mRNA水平的影响需要更高剂量的LHRH（10 nM）或更长的孵育时间（64小时）。用0.1 nM生长激素释放因子（GRF）处理培养物40小时，使含有GH mRNA的[³H]T标记细胞数量增加54%，对GH蛋白进行免疫染色的细胞数量增加30%。同时向培养物中添加LHRH（1 nM）可完全阻断GRF的后一种作用。在没有GRF的情况下，LHRH（1 nM）对含有GH mRNA的细胞总数也有抑制作用，对GH蛋白染色的细胞总数有类似作用。目前的数据表明，LHRH能够抑制培养的新生大鼠垂体中生长激素细胞的GRF非依赖性和GRF依赖性发育。
