Question

where does testosterone is synthesised ​

Answer 1

Testosterone is produced by the gonads (by the Leydig cells in testes in men and by the ovaries in women)

Answer 2

The amount of testosterone synthesized is regulated by the hypothalamic–pituitary–testicular axis (see figure to the right). When testosterone levels are low, gonadotropin-releasing hormone (GnRH) is released by the hypothalamus, which in turn stimulates the pituitary gland to release FSH and LH.