Three different hormonal events occur that signal the onset of puberty (from the Latin puber, meaning “adult”). The hypothalamus increases production of gonadotropin-releasing hormone (GnRH). This stimulates the endocrine cells in the anterior lobe of the pituitary gland, causing circulating levels of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) to rise rapidly. Finally, in response to increased levels of FSH and LH, the ovaries and testes secrete increased amounts of androgens and estrogens. The secondary sex characteristics appear, gamete production begins, and there is a sudden increase in the growth rate, culminating in the closure of the epiphyseal cartilages.