BACKGROUND: Impaired GH secretion is a common finding in patients with primary hyperparathyroidism (PHP). Ghrelin displays strong GH-releasing action, mainly at the hypothalamic level. OBJECTIVE: To evaluate secretory response of GH to ghrelin in PHP patients. PATIENTS: Fifteen patients [11 women/4 men, mean age 54 years, range 32-70 years, body mass index (BMI) 25.0 +/- 0.7 kg/m(2)] affected with PHP due to single parathyroid adenoma and 35 normal age-matched subjects (23 women/12 men, mean age 58 years, range 35-68 years, BMI 24.1 +/- 1.1 kg/m(2)). METHODS: A measure of 1 microg/kg body weight i.v. acylated ghrelin or 1 microg/kg body weight i.v. GH releasing hormone (GHRH) followed by 0.5 g/kg body weight i.v. arginine (ARG) hydrochloride were administered to all subjects on alternate days in order to evaluate GH response. RESULTS: Mean serum GH peak after GHRH + ARG was 32.6 +/- 7.8 and 17.4 +/- 4.0 microg/l, in controls and PHP patients, respectively (P < 0.05). Mean serum GH peak after ghrelin was 70.4 +/- 31.5 and 16.8 +/- 1.9 microg/l, in controls and PHP patients, respectively, (P < 0.001). Using ROC curves, a serum GH peak > 22 microg/l after ghrelin stimulation might be considered as a cut-off value for identifying normal subjects. Ten (67%) PHP patients have impaired GH response to GHRH + ARG and 13 (87%) to ghrelin. Serum GH peak after ghrelin or GHRH + ARG was unrelated to serum IGF-1, PTH or ionized calcium concentrations. CONCLUSIONS: The present data confirm that GH secretion is impaired in PHP patients using the potent GH secretagogue ghrelin and suggest that impaired GH secretion is likely due to a deleterious effect of hypercalcaemia at the hypothalamic level in PHP patients
Primary hyperparathyroidism is associated with marked impairment of GH response to acylated ghrelin
BROGLIO, Fabio;GHIGO, Ezio;
2008-01-01
Abstract
BACKGROUND: Impaired GH secretion is a common finding in patients with primary hyperparathyroidism (PHP). Ghrelin displays strong GH-releasing action, mainly at the hypothalamic level. OBJECTIVE: To evaluate secretory response of GH to ghrelin in PHP patients. PATIENTS: Fifteen patients [11 women/4 men, mean age 54 years, range 32-70 years, body mass index (BMI) 25.0 +/- 0.7 kg/m(2)] affected with PHP due to single parathyroid adenoma and 35 normal age-matched subjects (23 women/12 men, mean age 58 years, range 35-68 years, BMI 24.1 +/- 1.1 kg/m(2)). METHODS: A measure of 1 microg/kg body weight i.v. acylated ghrelin or 1 microg/kg body weight i.v. GH releasing hormone (GHRH) followed by 0.5 g/kg body weight i.v. arginine (ARG) hydrochloride were administered to all subjects on alternate days in order to evaluate GH response. RESULTS: Mean serum GH peak after GHRH + ARG was 32.6 +/- 7.8 and 17.4 +/- 4.0 microg/l, in controls and PHP patients, respectively (P < 0.05). Mean serum GH peak after ghrelin was 70.4 +/- 31.5 and 16.8 +/- 1.9 microg/l, in controls and PHP patients, respectively, (P < 0.001). Using ROC curves, a serum GH peak > 22 microg/l after ghrelin stimulation might be considered as a cut-off value for identifying normal subjects. Ten (67%) PHP patients have impaired GH response to GHRH + ARG and 13 (87%) to ghrelin. Serum GH peak after ghrelin or GHRH + ARG was unrelated to serum IGF-1, PTH or ionized calcium concentrations. CONCLUSIONS: The present data confirm that GH secretion is impaired in PHP patients using the potent GH secretagogue ghrelin and suggest that impaired GH secretion is likely due to a deleterious effect of hypercalcaemia at the hypothalamic level in PHP patients
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