Figure 1.

This photomicrograph (at 400 power magnification) shows human osteoblasts in culture after 28 days stained to show Alkaline Phosphatase production as dark blue. (a) Estradiol at a physiological concentration. (b) Estradiol alone for 7 days combined with Progesterone for 21 days. Note the lack of alkaline phosphatase staining in (a) exposed to estrogen alone, and the marked ALP staining indicating osteoblast differentiation/maturation induced by the addition of progesterone, (b) This figure is reprinted from [20] with permission from authors (Schmidmayr M and Seifert-Klauss V). Publisher permission provided.