we conclude that older women require a greater parathyroid hormone stimulus than younger women to maintain vitamin d homeostasis , because of an age-related decline in the formation of 1,25 ( oh ) 2d in response to parathyroid hormone , and that in osteoporosis the age-appropriate parathyroid hormone response to the same hypocalcemic signal is diminished .
C0014695
vitamin d
C0029456
osteoporosis