Bone is a reproductive organ

It turns out that the hypothalamus-hypofisis-gonad axis, an established dogma describing the endocrine control of reproduction by hormones produced in the brain, is orthoghonally crossed by a second axis made of hormones  produced in peripheral organs. In females we have the liver (producing IGF-1, that we recently described to be integral in mediating female fertility) and in males the bone (secreting osteocalcin, that last week has been described to induce testosterone production in the male testes). The reproductive system is crucially complex.

Orthogonal axes in reproductive endocrinology: liver and bone secretes crucial hormones.
photo by fmagnifici