4764
In addition , although Lin28b and / or Lin28a expression significantly decreased prior to puberty , neither Let - 7a nor Let - 7g miRNA levels changed significantly , raising the possibility that some effects of Lin28b and Lin28a within the hypothalamic - pituitary - gonadal ( HPG ) axis may be Let - 7 miRNA independent .
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 None