Introduction: There is indirect evidence of unfavorable effects of parathyroid hormone (PTH) on glucose metabolism. Teriparatide (recombinant human PTH 1-34 - TPTD) has been recently available for the treatment of osteoporosis.
Aim: To evaluate the acute and chronic effect of TPTD on blood glucose and insulin levels in women with established osteoporosis.
Patients and methods: Twenty-three postmenopausal women with established osteoporosis (mean age 65.6±1.8 years) received daily injections of 20 μg TPTD for six months. Three oral glucose tolerance tests (OGTT) were performed: one day before the first injection (OGTT-basal), one hour after (OGTT-acute) and six months after initiation of therapy (OGTT-chronic).
Results: There were significant differences between the OGTT-basal and OGTT-acute values in glucose at 90 min (168.3±9.8 vs 180.6±9.2, P<0.05) and 120 min (152.0±8.7 vs 170.5±7.8, P<0.01), between the OGTT-basal and OGTT-chronic values for glucose at 90 min (168.3±9.8 vs 184.5±13.3, P<0.05) and between the OGTT-basal and OGTT-acute for insulin at 90 min (56.7±7.4 vs 68.7±8.2, P<0.01). These differences remained significant for the subgroup of patients with normal (n=8) but not impaired glucose tolerance or diabetes mellitus (n=15).
Conclusions: TPTD seems to have an acute, subclinical adverse impact on stimulated glucose levels possibly due to insulin resistance. This impact is not seen at six months. On clinical grounds, it seems that TPTD administration has no significant impact on glucose metabolism in osteoporotic patients.