Penetration of peripheral glucose and insulin into cerebrospinal fluid in rats

1988 ◽  
Vol 255 (2) ◽  
pp. R200-R204 ◽  
Author(s):  
A. B. Steffens ◽  
A. J. Scheurink ◽  
D. Porte ◽  
S. C. Woods
Keyword(s):  
Cerebrospinal Fluid ◽  
Plasma Glucose ◽  
Plasma Insulin ◽  
Glucose Solution ◽  
Base Line ◽  
Jugular Veins ◽  
Left And Right ◽  
Freely Moving ◽  
Ad Libitum ◽  
Glucose Plasma

In this study the penetration of plasma insulin and glucose into the cerebrospinal fluid (CSF) was investigated. Rats were implanted with cannulas in the cisterna magna and into the left and right jugular veins. Freely moving rats were intravenously infused during 4 h with either glucose solution (10 mg/min) or saline. Before, during, and after the infusions, simultaneous blood and CSF samples were taken. Infusion of glucose led to an immediate rise of both plasma glucose and insulin. Although CSF glucose followed plasma glucose within 10 min, CSF insulin was unchanged until 40 min. After termination of the glucose infusion, levels of all substances returned to base line within 10 min. Twenty-four-hour food deprivation resulted in a significant decrease of plasma glucose, plasma insulin, CSF glucose, and CSF insulin. At the onset of eating after deprivation, an increase of plasma glucose and insulin occurred within 10 min, whereas CSF glucose was delayed between 10 and 40 min, after which ad libitum values were attained or surpassed. CSF insulin always remained below ad libitum levels. It is concluded that 1) glucose and insulin penetrate into the CSF and 2) CSF insulin and glucose can fulfill a putative feedback in homeostatic control of food intake and body weight.

Glycemic and Insulinemic Response to Preexercise Carbohydrate Feedings

1994 ◽  
Vol 4 (1) ◽  
pp. 46-53 ◽  
Author(s):  
John G. Seifert ◽  
Greg L. Paul ◽  
Dennis E. Eddy ◽  
Robert Murray
Keyword(s):  
Plasma Glucose ◽  
Plasma Insulin ◽  
Glucose Solution ◽  
Physiological Responses ◽  
Metabolic Responses ◽  
Moderate Intensity ◽  
Baseline Values ◽  
Glucose Plasma ◽  
Insulinemic Response

The effects of preexercise hyperinsulinemia on exercising plasma glucose, plasma insulin, and metabolic responses were assessed during 50 min cycling at 62%. Subjects were fed a 6% sucrose/glucose solution (LCHO) or a 20% maltodextrin/glucose solution (HCHO) to induce changes in plasma insulin. During exercise, subjects assessed perceived nauseousness and lightheadedness. By the start of exercise, plasma glucose and plasma insulin had increased. In the LCHO trial, plasma glucose values significantly decreased below the baseline value at 30 min of exercise. However, by 40 min, exercise plasma glucose and insulin values were similar to the baseline value. Exercise plasma glucose and insulin did not differ from baseline values in the HCHO trial. Ingestion of LCHO or HCHO was not associated with nausea or lightheadedness. It was concluded that the hyperinsulinemia induced by preexercise feediigs of CHO did not result in frank hypoglycemia or adversely affect sensory or physiological responses during 50 min of moderate-intensity cycling.

scholarly journals Comparison of the Effects of Acarbose and TZQ-F, a New Kind of Traditional Chinese Medicine to Treat Diabetes, Chinese Healthy Volunteers

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Huang Yuhong ◽  
Fu Wenxu ◽  
Li Yanfen ◽  
Liu Yu ◽  
Li Ziqiang ◽  
...  
Keyword(s):  
Chinese Medicine ◽  
Traditional Chinese Medicine ◽  
Adverse Events ◽  
Plasma Glucose ◽  
Plasma Insulin ◽  
Double Blind ◽  
C Peptide ◽  
Treatment Of Diabetes ◽  
Glucose Plasma ◽  
Gastrointestinal Adverse Events

Ethnopharmacological Relevance. TZQ-F has been traditionally used in Traditional Chinese Medicine as a formula for the treatment of diabetes.Aim of the Study. This study aims to compare the pharmacologic effects and gastrointestinal adverse events between TZQ-F and acarbose.Methods. The double-blind randomized placebo-controlled fivefold crossover study was performed in 20 healthy male volunteers. Plasma glucose, plasma IRI, and plasma C-peptide were measured to assess the pharmacologic effects. Flatus and bowel activity were measured to assess the adverse event of gastrointestinal effect.Results. 3 and 4 tablets of TZQ decreased theCmaxof plasma glucose compared with that of the previous day and with placebo. 3 tablets also decreasedCmaxof plasma C-peptide compared with placebo. 4 tablets increasedCmaxof plasma insulin after breakfast and the AUC of plasma C-peptide after breakfast and dinner. 2 tablets did not decrease plasma glucose and elevated theCmaxand AUC of C-peptide after breakfast and dinner, respectively. Acarbose 50 mg decreased theCmaxof plasma insulin and C-peptide after breakfast and theCmaxof plasma glucose and C-peptide after dinner. The subjects who received TZQ did not report any abdominal adverse events.Conclusions. 3 tablets of TZQ have the same effects as the acarbose.

Effects of glucagon-like peptide-I on glucose turnover in rats

1996 ◽  
Vol 270 (6) ◽  
pp. E1015-E1021 ◽  
Author(s):  
G. Van Dijk ◽  
S. Lindskog ◽  
J. J. Holst ◽  
A. B. Steffens ◽  
B. Ahren
Keyword(s):  
Plasma Glucose ◽  
Plasma Insulin ◽  
Glucose Turnover ◽  
Plasma Glucagon ◽  
Appearance Rate ◽  
Glucose Clearance ◽  
Peripheral Effect ◽  
Freely Moving ◽  
Glucagon Like Peptide ◽  
Fasted Rats

The influences of glucagon-like peptide-I-(7-36) amide (GLP-I; 15 mumol. kg-1.min-1) on glucose turnover were studied in freely moving Wistar rats. In fed rats, GLP-1 reduced plasma glucose (from 7.3 +/- 0.2 to 5.6 +/- 0.3 mmol/l; P = 0.017), increased plasma insulin (from 20 +/- 3 to 89 +/- 11 mU/l; P = 0.002), and reduced plasma glucagon (from 44 +/- 1 to 35 +/- 2 pg/ml; P = 0.009) and glucose appearance rate (Ra; from 3.9 +/- 0.2 to 1.7 +/- 0.7 micromol.min-1. 100 g-1 after 30 min; P = 0.049) without affecting glucose disappearance rate (Rd). The glucose clearance rate (MCR) was increased (P = 0.048). In 48-h-fasted rats, GLP-I reduced plasma glucose (from 5.0 +/- 0.2 to 4.4 +/- 0.3 mmol/l; P = 0.035) and increased plasma insulin (from 4 +/- 1 to 25 +/- 10 mU/l; P = 0.042) and plasma glucagon (from 43 +/- 3 to 61 +/- 7 pg/ml; P = 0.046). Ra and Rd were not significantly affected, although Ra was lower than Rd after 15-30 min (P = 0.005) and MCR was increased (P = 0.049). Thus GLP-I reduces Ra in fed rats and increases MCR in fed and fasted rats. The reduced Ra seems mediated by an increased insulin-to-glucagon ratio; the increased glucose clearance seems dependent on insulin and a peripheral effect of GLP-I.

scholarly journals The effect of ispaghula (Fybogel and Metamucil) and guar gum on glucose tolerance in man

1984 ◽  
Vol 51 (3) ◽  
pp. 371-378 ◽  
Author(s):  
H. A. Jarjis ◽  
N. A. Blackburn ◽  
J. S. Redfern ◽  
N. W. Read
Keyword(s):  
Gastric Emptying ◽  
Glucose Tolerance ◽  
Plasma Glucose ◽  
Plasma Insulin ◽  
Guar Gum ◽  
Normal Subjects ◽  
Oral Glucose ◽  
Diabetic Patients ◽  
Glucose Plasma ◽  
Insulin Responses

1. The effects of incorporating Fybogel (3·5 and 7 g doses), Metamucil (7 g) or guar gum (2·5 and 14·5 g doses) in a drink containing 50 g glucose on plasma glucose, plasma insulin and gastric emptying were studied in thirty-eight normal volunteers. In addition, the effects of Fybogel (7 g) on glucose tolerance, plasma insulin and gastric emptying were measured in fourteen non-insulin-dependent diabetics.2. Both doses of guar gum significantly lowered plasma glucose and plasma insulin responses to the oral glucose load in normal subjects, although 14·5 g guar gum did not delay the half-time for gastric emptying.3. Neither Fybogel nor Metamucil had significant effects on plasma glucose responses in normal subjects. In addition, Fybogel (at either dose) had no significant effects on plasma insulin levels, or on gastric emptying in normal subjects or on plasma glucose and insulin responses in diabetic patients.4. The viscosity of ispaghula solutions (Fybogel) was lower than that of guar gum solutions.

Pre- and postabsorptive insulin secretion in chronic decerebrate rats

1986 ◽  
Vol 250 (4) ◽  
pp. R539-R548 ◽  
Author(s):  
F. W. Flynn ◽  
K. C. Berridge ◽  
H. J. Grill
Keyword(s):  
Insulin Secretion ◽  
Plasma Glucose ◽  
Plasma Insulin ◽  
Oral Glucose ◽  
Base Line ◽  
Intravenous Glucose ◽  
Insulin Levels ◽  
Glucose Levels ◽  
Percent Change ◽  
Plasma Insulin Levels

Basal, taste-stimulated (preabsorptive), and postabsorptive insulin secretion and plasma glucose responses were studied in chronic decerebrate rats and their pair-fed neurologically intact controls. In experiment 1, preabsorptive insulin responses (PIR) elicited by oral infusions of glucose solution was measured in chronic decerebrate rats. Oral glucose was ingested and led to a significant short-latency elevation in plasma insulin levels. Plasma glucose levels remained constant during this time. These data show that caudal brain stem mechanisms, in isolation of the forebrain, are sufficient for the neurally mediated PIR elicited by oral glucose stimulation. In experiment 2, effects of decerebration on postabsorptive insulin secretion were measured. During the 3 h immediately after transection there was no effect of decerebration on peripheral plasma insulin or glucose levels. Thereafter, however, basal plasma insulin levels of decerebrate rats were at least twice that of control rats. Plasma glucose levels of both groups remained identical despite the hyperinsulinemia in decerebrate rats. Atropine treatment decreased, and phentolamine administration elicited a greater absolute and percent change increase in insulin levels of decerebrate rats. These data indicate that altered autonomic tone contributes to maintaining the basal hyperinsulinemia in the decerebrate rat. In response to intragastric meals and glucose and intravenous glucose administration, insulin secretion was greater in decerebrate than in control rats. Percent change in insulin levels from base line was similar in both groups after intragastric meals and intravenous glucose. In response to intragastric glucose, however, percent increase in insulin levels was greater in decerebrate rats. Decerebrate rats demonstrated mild glucose intolerance after intragastric and intravenous treatments. These results are contrasted with the known effects of ventromedial hypothalamic lesions on insulin secretion and glucose homeostasis.

Beta-endorphin-induced hyperglycemia in rabbits: effects of a glucose or arginine challenge

1987 ◽  
Vol 252 (2) ◽  
pp. E255-E259 ◽  
Author(s):  
R. L. Schleicher ◽  
R. K. Chawla ◽  
P. A. Coan ◽  
D. Martino-Saltzman ◽  
D. C. Collins
Keyword(s):  
Plasma Glucose ◽  
Plasma Insulin ◽  
Peak Plasma ◽  
Control Group ◽  
Base Line ◽  
Arginine Infusion ◽  
Insulin Levels ◽  
Beta Endorphin ◽  
Glucose Levels ◽  
Glucose Challenge

The effects of beta-endorphin on glucose, insulin, and glucagon levels were studied in normal fasted adult male rabbits. An intravenous bolus of glucose (0.7 g/kg body wt) produced a hyperglycemic state (peak plasma glucose 306 +/- 22 mg/dl; means +/- SE) that lasted approximately 90 min. beta-Endorphin (31 micrograms/g body wt; iv) administered immediately prior to the glucose challenge resulted in plasma glucose levels that were significantly higher from 10 to 90 min after the glucose challenge (P less than 0.001-0.05). From 10 to 30 min, plasma insulin levels were significantly lower in the beta-endorphin group (P less than 0.001-0.05), peaking at one-half the control group levels. Glucagon levels were unchanged by the glucose bolus in either the control or beta-endorphin-treated group (means +/- SE = 102.8 +/- 4 pg/ml). In another experiment, a 30-min infusion of L-arginine (13 mg-1 X kg body wt-1 X min iv) in normal fasted rabbits produced a rapid (10 min) increase in plasma insulin and glucagon and a return to base-line levels 60 min after withdrawing the arginine stimulus. Plasma glucose levels were not altered by arginine (mean +/- SE = 94.5 +/- 1 mg/dl). Administration of beta-endorphin (31 micrograms/kg body wt iv) at the start of the arginine infusion resulted in a rapid (10 min) and long-lasting (up to 60 min) hyperglycemic effect associated with a significant decrease in insulin levels (10-20 min; P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Early insulin response after food intake in geese

1992 ◽  
Vol 263 (4) ◽  
pp. R782-R784
Author(s):  
H. Karmann ◽  
N. Rideau ◽  
T. Zorn ◽  
A. Malan ◽  
Y. Le Maho
Keyword(s):  
Insulin Secretion ◽  
Plasma Glucose ◽  
Plasma Insulin ◽  
Insulin Response ◽  
Insulin Level ◽  
Food Ingestion ◽  
Standard Meal ◽  
Cephalic Phase ◽  
Early Insulin Response ◽  
Freely Moving

Plasma glucose and insulin levels were measured in chronically catheterized, freely moving, undisturbed geese, which were offered a free standard meal after an overnight fast. The insulin level markedly rose within the first minute after the start of food ingestion, whereas plasma glucose did not increase. This early insulin response was not correlated with the size of the meal. In contrast, both postabsorptive insulin response and plasma glucose changes were dependent on meal size. When a small amount of food (2-6 g) was eaten, insulin returned to basal level within 30 min, whereas plasma glucose remained unchanged. Larger meals (15-20 g) maintained plasma insulin at a higher level and induced a sustained rise of plasma glucose. These results indicate that there is a cephalic phase of insulin secretion at the beginning of the meal in birds as previously described in mammals.

Oral insulin in diabetic dogs

1991 ◽  
Vol 131 (2) ◽  
pp. 267-278 ◽  
Author(s):  
M. Saffran ◽  
J. B. Field ◽  
J. Peña ◽  
R. H. Jones ◽  
Y. Okuda
Keyword(s):  
Portal Vein ◽  
Plasma Flow ◽  
Plasma Glucose ◽  
Plasma Insulin ◽  
Hepatic Glucose Production ◽  
Glucose Production ◽  
Crystalline Insulin ◽  
Hepatic Glucose ◽  
Glucose Plasma ◽  
Oral Doses

ABSTRACT Bovine crystalline insulin, mixed with an absorption enhancer, was loaded by hand into gelatin capsules, which were then coated with an azopolymer designed to deliver the insulin in the upper colon. In 34 experiments with 14 pancreatectomized mongrel dogs of both sexes, the coated capsules were administered orally after a pre-dose period of 1 h. The dogs had cannulae in the portal vein, hepatic vein and femoral artery and Doppler flow probes on the portal vein and hepatic artery. Insulin and food were withdrawn the day before an experiment. Responses measured were plasma glucose, plasma insulin, hepatic glucose production rate, hepatic plasma flow rate and plasma glucagon-like immunoactivity (GLI). Control experiments, with capsules without insulin, produced small changes from 'pre-dose' values. Insulin-containing capsules, without the azopolymer coating, resulted in some early changes consistent with upper gastrointestinal absorption. Single oral doses (66 to 400 nmol/kg) of insulin in completely coated capsules produced peaks of portal plasma insulin and transient decreases in plasma glucose, hepatic glucose production, hepatic plasma flow and plasma GLI. The changes usually began 1·5–2 h after administration of a single dose, and lasted for up to 3 h, but were not significantly related to the dose of insulin. Multiple oral doses of insulin, given at 1·5-h intervals, resulted in multiple peaks of plasma insulin, a continuing dose-dependent fall in plasma glucose to near-euglycaemia with the highest dose, and profound decreases in hepatic glucose production and plasma GLI. These data demonstrate that insulin absorbed from the gastrointestinal tract causes changes in glucose metabolism in the diabetic dog that are consistent with the action of insulin primarily on the liver and that repeated oral doses are necessary to correct the hyperglycaemia. Journal of Endocrinology (1991) 131, 267–278

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