Table 1. Skeletal parameters altered by disruption of FSH in the HPG axis.
| Genotype | Reproductive effects | Skeletal effects | Following OVX | Reference |
|---|---|---|---|---|
| F ORKO | Immature ovary development, thread-like uteri | Spinal kyphosis, vertebral compression (4 mo) | Decreased BMD, BV/TV (spine, femur) | 2, 3, 4 |
| Decreased circulating estrogen | Decreased BMD, Tb BV, ObS/BS, MAR, BFR at 3-4 | Increased OcS/BS | ||
| Increased FSH, LH | mo. (spine, femur) | Decreased testosterone | ||
| 10-fold increase in testosterone at 3-4 mo. | Decreased ex vivo osteoclastogenesis | OVX effect is mimicked by androgen receptor blockade or aromatase inhibition | ||
| Inhibin – not determined | ||||
| FSHβ +/- | Normal ovaries and uteri | Decreased osteoclast number | Not determined | 1, 3 |
| Normal estrogen | Decreased bone resorption | |||
| 50% decreased FSH | Increased Tb BV, Tb N (spine, femur) | |||
| Inhibin, testosterone, LH – not determined | No changes in serum osteocalcin, MAR | |||
| FSHβ -/- | Atrophic ovaries, Thread-like uteri | No bone loss | Not determined | 1, 3 |
| Decreased estrogen | Increased BMD (femur) | |||
| Decreased FSH; Increased LH | Increased BV/TV, Tb N | |||
| Inhibin, testosterone – not determined | ||||
References: 1. Kumar, 1997; 2. Danilovich, 2000, 2002; 3. Sun, 2006; 4. Gao, 2007
BMD, bone mineral density; Tb BV, trabecular bone volume; ObS/BS, osteoblast Surface/bone surface; MAR, mineral apposition rate; BFR, bone formation rate; BV/TV, bone volume/total volume; OcS/BS, osteoclast surface/bone surface; Tb N, trabecular number