Puberty is the time in an individual’s life when they physically become sexually mature and able to have children. Precocious refers to puberty occurring at an earlier age than the average age among an individual’s peers. Generally, puberty is considered precocious if it begins before the age of 8 in females and the age of 9 in males.
The hypothalamic-pituitary-gonadal axis is a system of hormone signaling between the hypothalamus, pituitary gland, and gonads, either the testes or ovaries, to control sexual development and reproduction. Gonadotropin-releasing hormone is released by the hypothalamus into the hypophyseal portal system, which is a network of capillaries connecting the hypothalamus to the hypophysis, or the pituitary. When gonadotropin-releasing hormone reaches the pituitary gland, it stimulates cells in the anterior pituitary, called gonadotrophs, to release gonadotropin hormones — luteinizing hormone and follicle-stimulating hormone — into the blood. These gonadotropin hormones then stimulate the gonads to produce specific steroids, sex hormones.
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.