Effects of beta-aminoproprionitrile on formation and mineralization of rat bone matrix.

Bones of 4-week-old Sprague-Dawley rats fed a diet containing 0.25% beta-aminoproprionitrile (beta-APN) for 21 days and injected with 3H-proline, 3H-tetracycline, and cold tetracycline at 5-, 10-, and 20-day intervals were analyzed for incorporation of 3H-proline and 3H-tetracycline. Tibial cross sections were examined by fluorescent microscopy to determine the linear bone apposition between intervals and the distribution and intensity of tetracycline bands. The incorporation of 3H-proline was similar in beta-APN-treated and control rats. Incorporation of 3H-tetracycline, however, was significantly lower in beta-APN-treated rats. Fluorescent microscopy of tibial cross sections showed a comparable amount of linear matrix apposition in control and treated rats. It is suggested that beta-APN does not inhibit the bone matrix formation but does interfere with its mineralization.