The Effect of Ethanol Extract of Piper nigrum L. Fruit on Reproductive System in Adult Male Wistar Rats: A Study of FSH, LH, Testosterone Level and Spermatogenic Cells - Ekaputri, Tia Wida; Master Programme, Basic Medical and Biomedical Science, Faculty of Medicine, Universitas Gadjah Mada, Indonesia (Faculty of Pharmacy Universitas Gadjah Mada, Yogyakarta, Skip Utara, 55281, Indonesia, 2018)