Growth hormone secretion in response to glucagon stimulation test in healthy middle-aged men.

OBJECTIVE: To investigate the growth hormone (GH) response to glucagon stimulation test (GST) in a population of healthy men over 50 years old in comparison to insulin tolerance test (ITT), analysis of the spontaneous 24-hour GH profile and insulin-like growth factor 1 (IGF-I). METHODS: 27 healthy men aged between 51 and 65 years were tested. RESULTS: Using non-parametric correlation analysis, a positive correlation between GH peak after GST and mean IGF-I (r = 0.528; p = 0.005) was found, as well with GH peak in 24-hour profile (r = 0.494; p = 0.009). No correlation was found comparing GH peak after ITT with the same parameters. Ten subjects presented GH peak of less than 3.0 microg/L after GST, none confirmed in ITT. CONCLUSIONS: GH peak response to GST was lower than ITT, but it showed a positive correlation with mean IGF-I and also with GH peak in 24-hour profile. However, GST should not be used to differentiate organic growth hormone deficiency (GDH) from the expected decline on GH secretion due to aging.

Growth hormone secretion in response to glucagon stimulation test in healthy middle-aged men / Secreção do hormônio do crescimento em resposta ao teste de estímulo com glucagon em homens saudáveis de meia-idade

OBJECTIVE: To investigate the growth hormone (GH) response to glucagon stimulation test (GST) in a population of healthy men over 50 years old in comparison to insulin tolerance test (ITT), analysis of the spontaneous 24-hour GH profile and insulin-like growth factor 1 (IGF-I). METHODS: 27 healthy men aged between 51 and 65 years were tested. RESULTS: Using non-parametric correlation analysis, a positive correlation between GH peak after GST and mean IGF-I (r = 0.528; p = 0.005) was found, as well with GH peak in 24-hour profile (r = 0.494; p = 0.009). No correlation was found comparing GH peak after ITT with the same parameters. Ten subjects presented GH peak of less than 3.0 μg/L after GST, none confirmed in ITT. CONCLUSIONS: GH peak response to GST was lower than ITT, but it showed a positive correlation with mean IGF-I and also with GH peak in 24-hour profile. However, GST should not be used to differentiate organic growth hormone deficiency (GDH) from the expected decline on GH secretion due to aging.

OBJETIVO: Investigar a resposta do hormônio do crescimento (GH) ao teste de estímulo com glucagon (GST) numa população de homens saudáveis acima dos 50 anos de idade, em comparação ao teste de tolerância à insulina (ITT), além da análise do perfil de secreção espontânea de GH nas 24 horas e fator de crescimento semelhante à insulina (IGF-I) basal. MÉTODOS: 27 homens, com idades entre 51 e 65 anos, foram submetidos aos testes. RESULTADOS: Utilizando análise de correlação não paramétrica, encontrou-se correlação positiva entre o pico de GH pós-GST e a média de IGF-I (r = 0,528; p = 0,005), e também com o pico espontâneo do GH no perfil de 24 horas (r = 0,494; p = 0,009). Não houve correlação do pico de GH pós-ITT com os mesmos parâmetros. Dez indivíduos apresentaram pico de GH após GST inferior a 3,0 μg/L, sem confirmação no ITT. CONCLUSÕES: O pico de GH pós-GST foi menor do que o obtido pós-ITT, porém demonstrou correlação positiva com a média de IGF-I e o pico de GH na secreção espontânea de 24 horas. Entretanto, o GST não demonstrou ser um bom teste para distinguir entre deficiência de hormônio de crescimento (DGH) e somatopausa.

Reduced relative lymphocyte count in african-americans with decompensated heart failure.

BACKGROUND: A reduction in relative lymphocyte count (%L) has been reported in whites with heart failure that inversely correlated with jugular venous pressure thereby implicating systemic venous hypertension with splanchnic congestion. OBJECTIVES: : To study whether a reduced %L (<20%) occurs in African-Americans (AA) with heart failure and to address pathophysiologic mechanisms having the potential to influence lymphocyte biology and survival, we monitored patients with or without systemic venous hypertension, hypoalbuminemia, hypovitaminosis D, and secondary hyperparathyroidism. METHODS: In 131 AA (90 men; 53 +/- 12 years): 113 were hospitalized, 50 with decompensated biventricular failure (DecompHF), 24 with acute left heart failure, and 39 with heart disease, but no heart failure (HDNHF); and 18 were outpatients with compensated heart failure. At the time of admission or outpatient visit, we monitored: white blood cell count and %L; and serum albumin, 25(OH)D, and parathyroid hormone (PTH). RESULTS: White blood cell count did not differ among the groups, whereas %L was reduced only in those with DecompHF (15 +/- 1%; P < 0.05) versus 25 +/- 2% with left heart failure, 29 +/- 1% in HDNHF, and 28 +/- 3% in compensated heart failure. Serum albumin was reduced in DecompHF (2.8 +/- 0.1; P < 0.05), but not in any of the other groups. Reduced 25(OH)D (<30 ng/mL), in keeping with hypovitaminosis D, was found in all AA, whereas elevated serum PTH (>65 pg/mL) was found only in those with DecompHF (123 +/- 22 pg/mL). CONCLUSIONS: A relative lymphocytopenia, together with hypoalbuminemia and elevated PTH, were found only in hospitalized AA with DecompHF. These findings implicate splanchnic congestion and the enteric loss of lymphocytes and albumin with an associated secondary hyperparathyroidism.