Question: ​on which organ or tissue does leptin primarily act
[{'answer': 'adipose tissue', 'provenance': [{'wikipedia_id': '214938', 'title': 'Leptin', 'start_paragraph_id': 73, 'start_character': 56, 'end_paragraph_id': 73, 'end_character': 70, 'bleu_score': 1.0, 'section': 'Section::::Sites of synthesis.\n'}]}, {'provenance': [{'wikipedia_id': '214938', 'title': 'Leptin', 'start_paragraph_id': 8, 'start_character': 0, 'end_paragraph_id': 8, 'end_character': 508, 'bleu_score': 0.972782728923768, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 1053706302631666504}, 'section': 'Section::::Effects.\n'}]}]