Secretion of human growth hormone and insulin in levodopa test during carbamazepine therapy

A blend of chlorophytum borivilianum and velvet bean increases serum growth hormone in exercise-trained men

Background:

Several isolated ingredients have been proposed to increase growth hormone (GH) release, including Chlorophytum borivilianum and Velvet bean. A combination of these two ingredients has been packaged within an investigational dietary supplement. It was the purpose of the present investigation to determine the impact of acute ingestion of this supplement on circulating GH in healthy, exercise-trained men.

Methods:

Fifteen men ingested the dietary supplement on two different days, separated by one week. Blood was collected from subjects before ingestion of the supplement and at 20, 40, 60, 80, 100, and 120 minutes post ingestion. GH was analyzed in serum samples using an ELISA method. Values for GH for each subject, at each collection time, were averaged over both test days and used in the main analysis.

Results:

Serum GH increased over time, with higher values at 60 minutes (1.56 ± 0.65 ng · mL⁻¹; P = 0.04; +767%), 80 minutes (1.76 ± 0.69 ng · mL⁻¹; P = 0.02; +878%), and 100 minutes (1.48 ± 0.62 ng · mL⁻¹; P = 0.05; +722%) compared to pre ingestion (0.18 ± 0.04 ng · mL⁻¹). A great deal of subject variability existed in the area under the curve (AUC) for GH, with pooled values ranging from 0.49 to 61.2 ng · mL⁻¹ · 2 hr⁻¹

Conclusion:

Acute ingestion of an investigational dietary supplement containing the active ingredients Chlorophytum borivilianum and Velvet bean results in an increase in circulating GH in exercise-trained men. Additional placebo controlled investigations are needed to extend these findings. Moreover, studies are needed to determine if chronic use of such supplementation leads to favorable changes in health-related parameters associated with increased circulating GH.

Insulin secretion in alcoholics in a withdrawal state

Insulin secretion was studied after stimulation with oral glucose and intravenous glucagon in 23 chronic alcoholics in a withdrawal state. Each subject was studied twice at one week's interval between the examinations. The insulin and C-peptide responses to glucagon were lower in the early withdrawal state. Moreover, the insulin and C-peptide increments were, when related to the magnitude of the glycemic stimulus, lower in the early than in the late withdrawal state. The fasting values of blood glucose, insulin and C-peptide and the blood glucose and C-peptide levels after oral glucose were higher in the early withdrawal state. These findings indicate that glucose metabolism in alcoholics in a withdrawal state can be disturbed by impaired insulin secretion and insulin resistance.

Insulin sensitivity in alcoholics in a withdrawal state

Insulin sensitivity in non-diabetic alcoholics in a withdrawal state was investigated using a euglycaemic clamp technique on two occasions with an interval of 1 week. Insulin was infused at a rate of 40 mU m-2 min-1 (n = 9) and 20 mU m-2 min-1 (n = 9). Hepatic glucose production was estimated with tritiated glucose in six subjects. The fasting glucose level at the first examination, 5.1 +/- 0.2 mmol l-1, exceeded that found at the second examination, 4.7 +/- 0.1 mmol l-1 (P less than 0.05), although the C-peptide concentration was higher at the first examination (2.7 +/- 0.3 vs. 1.6 +/- 0.2 ng ml-1; P less than 0.001). Both glucose uptake (5.0 +/- 0.6 vs 6.2 +/- 0.7 mg kg-1 min-1; P less than 0.05) and tissue sensitivity (M/I; 0.08 +/- 0.02 vs. 0.1 +/- 0.02 mg kg-1 min-1/mU l-1; P less than 0.05) increased between the first and second euglycaemic clamp (40 mU m-2 min-1). At the low insulin infusion rate (20 mU m-2 min-1), the tissue sensitivity to insulin increased (0.09 +/- 0.01 vs. 0.13 +/- 0.02 mg kg-1 min-1/mU l-1; P less than 0.05). Hepatic glucose production did not change during the examination period (2.2 +/- 0.2 vs. 2.3 +/- 0.1 mg kg-1 min-1), neither was there a change in the suppression of hepatic glucose output during hyperinsulinaemia (40 mU m-2 min-1). Our findings indicate that, in non-diabetic alcoholics, insulin sensitivity in peripheral tissues is decreased during the early part of a withdrawal period.

Effects of carbamazepine on cerebrospinal fluid somatostatin

This paper reports the reduction of the concentration of the neuropeptide somatostatin in the CSF of patients with affective illness during treatment with the anticonvulsant carbamazepine. None of the other psychotropic agents used in this study similarly affected CSF somatostatin, although zimelidine appeared to increase CSF somatostatin in a small number of patients. The potential mechanism and significance of the effects of carbamazepine on CSF somatostatin are discussed in relation to the psychotropic, anticonvulsant, and analgesic properties of carbamazepine.