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Given an abstract of a paper, generate a title for this paper such that conveys the key focus of the paper.

Abstract: When bovine parathyroid cells in culture are exposed to the active vitamin D metabolite 1,25(OH)2D3, a significant decrease in the steady-state levels of pre-proparathyroid hormone (pre-proPTH) mRNA occurs. The possibility that the fall in specific mRNA is due to a decrease in rate of transcription of the PTH gene was examined in this study. In the presence of 1,25(OH)2D3, there was a rapid and steady decline in PTH gene transcription rate which fell to a minimum of 10-15% of control at 24 h. The effect was observed at physiological levels (10(-11)M) and was also fully reversible.
Output:
Suppression by 1,25(OH)2D3 of transcription of the pre-proparathyroid hormone gene.