Puberty is the time in an individual’s life when they physically become sexually mature and able to have children. Generally speaking, it’s considered delayed if puberty hasn’t started for a female by age 13 and for a male by age 14.
The hypothalamic (HYpo-tha-lamb-ic)-pituitary-gonadal (Go-nad-al) axis is a system of hormonal signaling between the hypothalamus, pituitary gland, and gonads, the gonads are either the testes or the ovaries, and this will control sexual development and reproduction. Gonadotropin (Go-nad-ah-tro-pin) -releasing hormone is released into the hypophyseal (high-poth-ah-see-al) portal system, which is a network of capillaries connecting the hypothalamus to the hypophysis (high-pof-o-sis), or pituitary. When gonadotropin(Go-nad-ah-tro-pin) -releasing hormone reach the pituitary gland, it stimulates cells in the anterior pituitary, called gonadotrophs (Go-nad-a-trofs), to release gonadotropin hormones: luteinizing hormone and follicle-stimulating hormone which then enter the blood. These gonadotropin hormones then stimulate the gonads to produce sex specific hormones. These are estrogen and progesterone in females and testosterone is the major sex specific hormone in males.
Early on in male development, testosterone helps the external sex organs to differentiate into male genitals and causes the testes to descend from the abdomen into the scrotal sac. Beginning at puberty, the Leydig cells of the testes respond to the luteinizing hormone by converting more cholesterol into testosterone. In addition, the Sertoli cells of the testes respond to follicle-stimulating hormone by producing more sperm. The major sex specific hormones in women are estrogen and progesterone, and they are produced by the ovarian follicles that are scattered on the ovaries. Each ovarian follicle is made up of a ring of granulosa and theca cells surrounding a primary oocyte at its core. Beginning at puberty, theca cells respond to luteinizing hormone by producing androstenedione, an androgen. Then, the granulosa cells respond to follicle stimulating hormone by converting the androstenedione into estrogen and progesterone.