Cartilage of the baboon contains estrogen receptors.

Castrated-adrenalectomized aged female baboons were injected with 3H-estradiol-17 B (E2) and killed one hour later. Specimens from all regions of the larynx and oral cavity were taken and processed for autoradiography. A consistent and heavy uptake of 3H-E2 by the perichondrium and cartilage was found in all laryngeal sections with cartilage present and in the articular cartilage of the condyle of the mandible. These data provide evidence that cartilage contains receptors for estrogen. These data along with data already present in the literature suggest that circulating estrogen may act directly on cartilage to modulate collagen synthesis and further that the loss in circulating estrogen associated with menopause might in part explain the large sexual dimorphism associated with the incidence of osteoarthritis.