BGLAP and hypogonadism: The fact that mice lacking Osteocalcin or Gprc6a only in Leydig cells develop hypogonadism in the face of high circulating luteinizing hormone (LH) levels made one important and novel point of physiology: What it meant is that bone via osteocalcin signaling in the testes is a physiological regulator of steroidogenesis in the testes even in the face of normal pituitary functions.