Acid-base Homeostasis in Children With Growth Hormone Deficiency

To determine whether children with growth hormone deficiency (GHD) have lower mean serum bicarbonate concentrations than do children with short stature due to other causes.

Materials and Methods: We evaluated one hundred short stature children, aged 5 to 15 years, attending the children's endocrine clinic at Motahari clinic, Shiraz, Iran, over a 6 month period. Demographic data and clinical features were recorded, laboratory investigations were performed, and bone ages were calculated. GHD was defined as serum GH concentration )10 ng/ml in response to L-dopa and clonidine, in addition a thorough work-up was performed to exclude any other known clinical conditions that might lead to growth retardation.

Results: Thirty one patients (31%) had GHD, 69 (69%) were not GH deficient, and one case had panhypopituitarism. Serum bicarbonate concentrations were significantly lower in GHD compared with non-GHD patients (15.68±2.79 versus 17.98±3.79 mEq/l, P=0.003). On the other hand, 52 (75%) GHD subjects and 22 (71%) non-GHD had arterial blood pH values below 7.35, the difference not being statistically significant. All GHD patients had abnormal serum bicarbonate levels versus 87% of non-GHD cases (P<0.05). GHD and non-GHD groups were comparable regarding mean age, sex, height SDS, BMI, severity of bone age delay, fasting blood sugar, serum cortisol level, and thyroid function test results.

Conclusion: The lower plasma bicarbonate concentrations in patients with GHD as compared to with idopathatic short stature patients demonstrate a possible role for growth hormone in the modulation of acid-base homeostasis.