PubMed Health⌕ Search

Biomedical subjects

G Reaven

Publications and source records attributed to G Reaven.

46 records · Page 3Linked to original sources
PubMed1980

Effect of age on leucine-induced insulin secretion by the beta-cell.

We have previously shown that aging is associated with a marked decrease in glucose-stimulated insulin release by the beta-cell. To determine whether this age-related defect occurs with other insulin secretagogues, we have investigated leucine-stimulated insulin release. Islets of Langerhans were isolated from 2- and 12-month-old rats, and incubated with 5-20 mM 5-20 mM leucine or with 16.7 mM glucose. Islets from 12-month-old rats showed a decline in rate of leucine-induced secretion as compared to islets of 2-month-old donors (i.e., mean (+/- SEM) insulin secretion at 20 mM leucine was 0.79 (+/- 0.06) and 1.17 (+/- 0.09) microU/min/islet), respectively for 12- and 2-month-old rats. beta-cell number is increased in islets from 12-month-old donors, and when this increase is taken into account, the average beta-cell from 12-month-old donors secretes only one-half the rate of beta-cells from 2-month-old donors. These findings are comparable to those seen after glucose-stimulation, and emphasize the potential global nature of the age-related defect in beta-cell function.

Aging↗
PubMed1977

Postprandial plasma-glucose and -insulin responses to different complex carbohydrates.

We have studied the effects of dextrose, rice, potato, corn, and bread on postprandial plasma glucose and insulin responses in 16 subjects. All carbohydrate loads were calculated to contain 50 gm. of glucose. The data demonstrate (1) that dextrose and potato elicited similar plasma glucose responses whereas rice, corn, and bread elicited lower responses; (2) similarly, dextrose and potato elicited similar and greater plasma insulin responses than rice and corn, with the response to bread being intermediate; (3) when the study group was divided in half, on the basis of each subject's one-hour plasma glucose response to dextrose, the differences in the plasma glucose and insulin responses were greater in the subjects with the highest glucose response to dextrose than in the low responders. In conclusion, there is a range of plasma-glucose and insulin responses to different complex carbohydrates, with rice and corn producing the lowest response curves. Furthermore, these differences are accentuated in patients with reduced glucose tolerance.

Blood Glucose↗
PubMed1976

Plasma glucose and insulin responses to orally administered simple and complex carbohydrates.

We have studied the effects of glucose, sucrose, and various starches on postprandial plasma glucose and insulin responses in 19 subjects. All carbohydrate loads were calculated to contain 50 gm. of glucose, and the response to each carbohydrate was tested twice: when given alone in a drink or when given in combination with other nutrients as a meal. The data demonstrate: (1) Glucose and sucrose elicited similar plasma glucose response curves, but sucrose elicited a somewhat greater (20 per cent) plasma insulin response. (2) Raw starch ingestion resulted in a 44 per cent lower glucose response and a 35-65 per cent lower insulin response than did either glucose or sucrose ingestion. (3) When carbohydrate was given as a meal the plasma glucose responses were 40-60 per cent lower than when the same carbohydrate was given as a drink, while the insulin responses were generally similar, and (4) when different cooked starches were compared, the plasma glucose and insulin responses to rice were significantly lower (50 per cent) than to potato. In conclusion, the size of the carbohydrate molecule appears to influence the postprandial glucose and insulin responses such that more complex carbohydrates (starches) elicit lower responses. This effect may be related to differences in digestion rather than to differences in absorption.

Adult↗