90379434 Bone cell responsiveness to transforming growth factor β, parathyroid hormone, and prostaglandin E2 in normal and postmenopausal osteoporotic women

257 * 4.8 mg per cubic centimeter per year (2.0 percent per year) (P c 0.001). Amenorrhea did not develop in any woman during the year of observation (only 2.7 percent of the cycles were > 36 dayslong). Gvulatory disturbances occurred in 29 percent of all cycles, however. Bone loss was strongly associated with these disturbances (r = 0.54.24 percent of the variance). The I3 women who had anovulatory cycles lost bone mineral at a rate 086.4 f 3.8 mg per cubic centimeter per year (4.2 percent per year). The women training for a marathon had menstrual cycles similar to those of the women in the other two groups. Conclusions: Decreases in spinal bone density among women with differing exercise habits correlated with asymptomatic disturbances of ovulation (without amenorrhea) and not with physical activity.

90379434 Bone eel1respan&eness to transforming growth factor 0, parntkyrokl hormone, and prastaglaodin & in normal and postmcwpausal

osteoporotic women

Lomri A.: Marie P.J. Unite I8 INSERM.

Hopiral Lmiboisiere, 6 rue Guy Parin. 75010 Paris

J. BONE MINER. RES. 1990 5/l I (I 149-l 155) We have shown previously that the decreased trabecular bone formation in osteoporotic postmenopausal women results from a reduced ability of osteoblastic cells to proliferate. In this study we have tested the possibility that bone cells from osteoporotic women with low bone formation have an abnormal responsiveness to hormonal or local mitogenic factors. Primary cultures of bone cells with osteoblastic characteristics were obtained by migration from the trabecular bone surface in osteoporotic postmenopausal women with high (n = 7) or low (n = 7) bone formation as evaluated histomorphometrically by the extent of double tetracycline-labeled surface (DLS). Control bone cells were obtained under identical conditions from eight normal age-matched postmenopausal women. Parameters of osteoblastic differentiation (alkaline phosphatase activity and osteocalcin production) were found to be normal and similar in bone cells from osteoporotic women with low or high DLS. In contrast, cell replication as evaluated by [3H]thymidine into DNA was 3.4-fold lower in the low DLS group compared to the high DLS group, confirming our previous tindings. Treatment of quiescent bone cells with TGF-fl (O.S-I @ml) for 24 h significantly stimulated DNA synthesis in osteoblastic cells from normal women and in bone cells from osteoporotic patients with low or high DLS, indicating a normal responsiveness to TGF-fl in these patients. We have compared the effect of parathyroidhormone (PTH) on bone cells from normal and osteoporotic women. Basal CAMP levels and the CAMP accumulation in response to (I-34)-hPTH were similar in bone cells from patients with low or high DLS and were not different from normal values. The responsiveness of bone cells from osteoporotic women to exogenous prostaglandin E2 (PGEz) was also evaluated. PGE, (24 h) produced a dose-related biphasic effect on DNA synthesis in bone cells from both normal and osteoporotic weomen. At low concentration (IO“ ’ M) PGE, increased DNA synthesis whereas at higher concentration (IO-’ M) it was inhibitory. CAMP production was increased by PGE, at doses that inhibited DNA synthesis. The responsiveness to PGE, was not different in normal bone cells and in cells from osteoporotic women with low and high DLS. These results indicate that the reduced bone cell proliferative capacity in osteoporotic postmenopausal women with low bone formation does not result from a lower than normal responsiveness to TGF-8, PTH, and PGE,.

90379436 Sex differences in peak adult bone mineral density Kelly P.J.; Twomey L.: Sambrook P.N.; Eisman J.A. Garvan Institute of Medical Research, St. VincentS Hospital. Sydney, NSW 2010

J. BONE MINER. RES. 1990 S/l I (I 169-l 175) Osteoporotic fractures are more common in women than men. Although accelerated bone loss following the menopause is recognized as of major importance, it is generally considered that a lower peak adult bone mass in females also contributes to their increased risk of osteoporosis in later life. To examine potential sex differences in peak adult bone mass we studied 29 pairs of dizygotic twins of differing within-pair sex in whom the female twin was premenopausal (mean age 37 years, range 21-55). Bone mineral density