Effect of metabolic control on parathyroid hormone secretion in diabetic patients

Abstract

The metabolic derangement caused by diabetes mellitus may potentially affect bone mineral metabolism. In the present study we evaluated the effect of diabetes metabolic control on parathyroid hormone (PTH) secretion during stimulation with EDTA infusion. The study was conducted on 24 individuals, 8 of them normal subjects (group N: glycated hemoglobin -HbA 1C = 4.2 ± 0.2%; range = 3.5-5.0%), 8 patients with good and regular metabolic control (group G-R: HbA 1C = 7.3 ± 0.4%; range = 6.0-8.5%), and 8 patients with poor metabolic control (group P: HbA 1C = 12.5 ± 1.0%; range: 10.0-18.8%). Blood samples were collected at 10-min intervals throughout the study (a basal period of 30 min and a 2-h period of EDTA infusion, 30 mg/kg body weight) and used for the determination of ionized calcium, magnesium, glucose and intact PTH. Basal ionized calcium levels were slightly lower in group P (1.19 ± 0.01 mmol/l) than in group N (1.21 ± 0.01 mmol/l) and group G-R (1.22 ± 0.01 mmol/l). After EDTA infusion, the three groups presented a significant fall in calcium, but with no significant difference among them at any time. Basal magnesium levels and levels determined during EDTA infusion were significantly lower (P<0.01) in group P than in group N. The induction of hypocalcemia caused an elevation in PTH which was similar in groups N and G-R but significantly higher than in group P throughout the infusion period (+110 min, N = 11.9 ± 2.1 vs G-R = 13.7 ± 1.6 vs P = 7.5 ± 0.7 pmol/l; P<0.05 for P vs N and G-R). The present results show that PTH secretion is impaired in patients with poorly controlled diabetes.

Lack of relationship between glycemic control and bone mineral density in type 2 diabetes mellitus

“…In addition, we did not observe the occurrence of physiological adaptations of secondary hyperparathyroidism in these patients. The present results agree with data obtained by our group in a previous study in which we evaluated basal and hypocalcemia-stimulated iPTH secretion induced by EDTA administration (23). In that study we did not observe an increase in iPTH secretion in patients with poorly controlled DM (23).…”

“…The present results agree with data obtained by our group in a previous study in which we evaluated basal and hypocalcemia-stimulated iPTH secretion induced by EDTA administration (23). In that study we did not observe an increase in iPTH secretion in patients with poorly controlled DM (23). Furthermore, in the present study we observed that the chronic lack of metabolic control in type 2 DM does not interfere with the state of vitamin D sufficiency.…”

Functional Hypoparathyroidism Among Type 2 Diabetic Patients on Hemodialysis: Impact of Glycemic Control.

“…This was in agreement with the findings detected by Paulo et al, [18],whoreported a statistical significant difference regarding fasting blood sugar, phosphorus and glycated hemoglobin in diabetic group compared to non diabetic group.Likewise ,Takeshi et al, [19], reported a high statistical significant difference between all groups regarding glycated hemoglobin. These results were in agreement with the study of Ahmed R. et al, [20], they reported a statistical significant difference between all diabetic and non-diabetic patients regarding HbA1c , fasting blood sugar ,serum albumin and phosphate .…”

“…Also, Paula et al, [18],found that serum HbA1c levels were independent correlated with the serum iPTH levels in diabetic group .The inverse correlation noted between blood glucose and parathyroid hormone suggest that hyperglycemia may have an inhibitory action on the synthesis and secretion of parathyroid hormone and it is attractive to speculate that hyperglycemia together with an insulin deficit may lead to a hypoparathyriod state and a downregulation of PTH receptors [25].…”

“…Paula et al, [18]detected the inhibitory effects of insulin on both the secretion and the action of iPTH in both primary and secondary hyperparathyroidism. however, it is still unclear asProcopio M and Borretta G [29] studies suggest that poor metabolic control per se, could inhibit low calcium-mediated iPTH secretion.Guh et al, [30]detected the protective effect of diabetic process on the development of hyperparathyroidism and development of an adynamic bone lesion.…”