EFFECT OF DECAPITATION ON THE DEVELOPMENT OF INSULIN SECRETION IN THE FOETAL RABBIT

1973 ◽  
Vol 57 (1) ◽  
pp. 23-31 ◽  
Author(s):  
P. M. B. JACK ◽  
R. D. G. MILNER
Keyword(s):  
Insulin Secretion ◽  
Plasma Insulin ◽  
Insulin Concentration ◽  
Β Cell ◽  
Plasma Insulin Concentration ◽  
Intrauterine Development ◽  
Foetal Head ◽  
Significant Difference ◽  
The Mean ◽  
Control Litter

SUMMARY One rabbit foetus in a litter was decapitated on day 24 of gestation. On day 29 the litter was killed and blood was collected from all foetuses for the measurement of plasma insulin concentration. The pancreas of the decapitated foetus and that of the control litter-mate with the nearest headless body weight were cut into pieces and incubated in a physiological buffer containing 0·6 or 3·0 mg glucose/ml. The pancreas of the decapitated foetus secreted significantly more insulin than that of the control foetus in either concentration of glucose in the medium. Higher insulin secretion from the decapitated foetus persisted for 4·5 h of incubation and was demonstrable in both the first 5 and subsequent 25 min of incubation when the pancreas was initially transferred to incubation medium containing 3·0 mg glucose/ml. The mean plasma insulin concentration of the foetuses decapitated on day 24 was higher on day 29 than that of the control foetuses but there was no significant difference between the concentration of insulin in the pancreas of the two groups of animals. The results indicate that removal of the foetal head influences the intrauterine development of the rabbit β-cell.

Sensitivity of insulin secretion to feedback inhibition by hyperinsulinaemia

1981 ◽  
Vol 98 (1) ◽  
pp. 81-86 ◽  
Author(s):  
Ralph A. DeFronzo ◽  
Christian Binder ◽  
John Wahren ◽  
Philip Felig ◽  
Eleuterio Ferrannini ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Plasma Glucose ◽  
Plasma Insulin ◽  
Feedback Inhibition ◽  
Normal Subjects ◽  
Insulin Concentration ◽  
Plasma Insulin Concentration ◽  
C Peptide ◽  
Endogenous Insulin ◽  
Arterial Plasma

Abstract. The ability of insulin to inhibit its own secretion was examined in 15 normal subjects given an intravenous infusion of insulin in a dose of 0.25, 0.50, 1.0, 5.0 or 10.0 mU/kg/min for two hours. Arterial plasma insulin concentration achieved during the infusion segregated into three levels of hyperinsulinaemia: 35 ± 1 (mean ± sem), 87 ± 15 and 828 ± 210 μU/ml. Plasma glucose concentration was kept constant at the basal level by a variable glucose infusion. Fasting C-peptide (0.29 ± 0.02 pmol/ml) fell significantly in all subjects during hyperinsulinaemia and reached a concentration of 0.19 ± 0.03 pmol/ml at 60 min and 0.14 ± 0.03 at 120 min after the start of the insulin infusion. The C-peptide response was not related to the infusion dose nor to the steady state plasma insulin concentration. It is concluded that (a) basal insulin secretion as evaluated from C-peptide measurements is inhibited by small (24 ± 3 μU/ml) physiological elevations in plasma insulin concentration independent of changes in plasma glucose, and (b) supraphysiological or even pharmacological elevations in plasma insulin do not result in a further decrease in endogenous insulin secretion above that achieved with mild hyperinsulinaemia.

Lipolytic suppression following carbohydrate ingestion limits fat oxidation during exercise

1997 ◽  
Vol 273 (4) ◽  
pp. E768-E775 ◽  
Author(s):  
Jeffrey F. Horowitz ◽  
Ricardo Mora-Rodriguez ◽  
Lauri O. Byerley ◽  
Edward F. Coyle
Keyword(s):  
Oxygen Consumption ◽  
Plasma Insulin ◽  
Fat Oxidation ◽  
Insulin Concentration ◽  
Peak Oxygen Consumption ◽  
Whole Body ◽  
Plasma Insulin Concentration ◽  
Carbohydrate Ingestion ◽  
The Mean

This study determined if the suppression of lipolysis after preexercise carbohydrate ingestion reduces fat oxidation during exercise. Six healthy, active men cycled 60 min at 44 ± 2% peak oxygen consumption, exactly 1 h after ingesting 0.8 g/kg of glucose (Glc) or fructose (Fru) or after an overnight fast (Fast). The mean plasma insulin concentration during the 50 min before exercise was different among Fast, Fru, and Glc (8 ± 1, 17 ± 1, and 38 ± 5 μU/ml, respectively; P< 0.05). After 25 min of exercise, whole body lipolysis was 6.9 ± 0.2, 4.3 ± 0.3, and 3.2 ± 0.5 μmol ⋅ kg−1 ⋅ min−1and fat oxidation was 6.1 ± 0.2, 4.2 ± 0.5, and 3.1 ± 0.3 μmol ⋅ kg−1 ⋅ min−1during Fast, Fru, and Glc, respectively (all P < 0.05). During Fast, fat oxidation was less than lipolysis ( P < 0.05), whereas fat oxidation approximately equaled lipolysis during Fru and Glc. In an additional trial, the same subjects ingested glucose (0.8 g/kg) 1 h before exercise and lipolysis was simultaneously increased by infusing Intralipid and heparin throughout the resting and exercise periods (Glc+Lipid). This elevation of lipolysis during Glc+Lipid increased fat oxidation 30% above Glc (4.0 ± 0.4 vs. 3.1 ± 0.3 μmol ⋅ kg−1 ⋅ min−1; P < 0.05), confirming that lipolysis limited fat oxidation. In summary, small elevations in plasma insulin before exercise suppressed lipolysis during exercise to the point at which it equaled and appeared to limit fat oxidation.

THE EFFECT OF A HIGH-FAT DIET ON GLUCOSE, INSULIN SENSITIVITY AND PLASMA INSULIN IN RATS

1968 ◽  
Vol 42 (4) ◽  
pp. 489-494 ◽  
Author(s):  
E. BLÁZQUEZ ◽  
C. LOPEZ QUIJADA
Keyword(s):  
Plasma Glucose ◽  
High Fat Diet ◽  
Plasma Insulin ◽  
Diet Group ◽  
Insulin Concentration ◽  
Control Group ◽  
High Fat ◽  
Plasma Insulin Concentration ◽  
The Mean

SUMMARY The influence of the diet on the levels of insulin was studied in rats on a high-fat diet. Plasma and glucose insulin concentrations of a control group and of rats on a high-fat diet were compared, and so was the insulin concentration in the pancreas of the two groups. The mean plasma insulin concentration in the control group was 40 μ-u./ml. and that of insulin extracted from the pancreas was 2·5 μg./100 mg. tissue; plasma glucose was 156 mg./100 ml. The animals fed on a high-fat diet showed diabetic features. The mean plasma insulin level was 9 μ-u./ml., and plasma glucose increased to 210 mg./100 ml. The insulin concentration in the pancreas was not significantly different from that in the controls. In vitro the epididymal fat and the diaphragm of the high-fat-diet group were less sensitive to insulin than the same tissues in the control group.

scholarly journals Lower iodine storage in the placenta is associated with gestational diabetes mellitus

BMC Medicine ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Kristof Y. Neven ◽  
Bianca Cox ◽  
Charlotte Cosemans ◽  
Wilfried Gyselaers ◽  
Joris Penders ◽  
...  
Keyword(s):  
Diabetes Mellitus ◽  
Insulin Resistance ◽  
Gestational Diabetes ◽  
Gestational Diabetes Mellitus ◽  
Cord Blood ◽  
Plasma Insulin ◽  
Cell Activity ◽  
Insulin Concentration ◽  
Β Cell ◽  
Plasma Insulin Concentration

Abstract Background The micronutrient iodine is essential for a healthy intrauterine environment and is required for optimal fetal growth and neurodevelopment. Evidence linking urinary iodine concentrations, which mainly reflects short-term iodine intake, to gestational diabetes mellitus (GDM) is inconclusive. Although the placental concentrations would better reflect the long-term gestational iodine status, no studies to date have investigated the association between the placental iodine load and the risk at GDM. Moreover, evidence is lacking whether placental iodine could play a role in biomarkers of insulin resistance and β-cell activity. Methods We assessed the incidence of GDM between weeks 24 and 28 of gestation for 471 mother-neonate pairs from the ENVIRONAGE birth cohort. In placentas, we determined the iodine concentrations. In maternal and cord blood, we measured the insulin concentrations, the Homeostasis Model Assessment (HOMA) for insulin resistance (IR) index, and β-cell activity. Logistic regression was used to estimate the odds ratios (OR) of GDM, and the population attributable factor (PAF) was calculated. Generalized linear models estimated the changes in insulin, HOMA-IR, and β-cell activity for a 5 μg/kg increase in placental iodine. Results Higher placental iodine concentrations decreased the risk at GDM (OR = 0.82; 95%CI 0.72 to 0.93; p = 0.003). According to the PAF, 54.2% (95%CI 11.4 to 82.3%; p = 0.0006) of the GDM cases could be prevented if the mothers of the lowest tertile of placental iodine would have placental iodine levels as those belonging to the highest tertile. In cord blood, the plasma insulin concentration was inversely associated with the placental iodine load (β = − 4.8%; 95%CI − 8.9 to − 0.6%; p = 0.026). Conclusions Higher concentrations of placental iodine are linked with a lower incidence of GDM. Moreover, a lower placental iodine load is associated with an altered plasma insulin concentration, HOMA-IR index, and β-cell activity. These findings postulate that a mild-to-moderate iodine deficiency could be linked with subclinical and early-onset alterations in the normal insulin homeostasis in healthy pregnant women. Nevertheless, the functional link between gestational iodine status and GDM warrants further research.

The effect of previous body condition on appetite and associated insulin profiles in sheep

1997 ◽  
Vol 64 (2) ◽  
pp. 247-252 ◽  
Author(s):  
A. M. Sibbald ◽  
S. M. Rhind
Keyword(s):  
Food Intake ◽  
Body Condition ◽  
Dry Matter ◽  
Plasma Insulin ◽  
Insulin Concentration ◽  
Feedback Signal ◽  
Plasma Insulin Concentration ◽  
Condition Score ◽  
The Mean ◽  
Ad Libitum

AbstractThe effect of previous level of body condition on appetite was studied in 47 housed Scottish Blackface ewes, which had been either thin (L: mean condition score 2·15, s.e. 0·030; no. = 24) or fat (H: mean condition score 3·15, s.e. 0·056; no. = 23) 8 weeks before the start of the experiment. The mean daily voluntary food intake (VFI) of a dried grass pellet diet was higher for the L than for the H ewes (2176 v. 1727 g dry matter per day; P < 0·001) during the first 6 weeks of the experiment (period 1). Over this time, live weights increased from 60·5 or 69·9 (s.e.d. 1·68) to 68·4 or 75·6 (s.e.d. 1·94) and condition scores increased from 2·84 or 3·16 (s.e.d. 0·057) to 3·13 or 3·38 (s.e.d. 0·071) for the L and H ewes respectively.At the end of the 6-week period, plasma insulin concentrations were measured in 10 ewes from each treatment (mean condition scores 3·15 (L) and 3·27 (H) (s.e.d. 0·091)) when fed both ad libitum and at a fixed level of 1200 g/day for consecutive 11-day periods (period 2). Mean VFI was higher for the L than for the H ewes (2191 v. 1661 g dry matter per day; P < 0·05) over the period of ad libitum feeding. There was no effect of feeding level (ad libitum v. 1200 g/day) on mean plasma insulin concentrations, but the mean basal plasma insulin concentration was higher in the H than in the L ewes (43·0 v. 29·0 mil per 1; P < 0·05). Fifteen minutes after the ingestion of a single 400 g meal, the plasma insulin concentration in the H ewes was higher than the mean prefeeding value (63·3 v. 41·7 mil per I; P<0·05) but there was no corresponding increase in the L ewes. The plasma insulin concentration 15 min after the intravenous administration of a single dose of 0·25 U per kg live weight of insulin ivas higher in the H than in the L ewes (1723 v. 1031 mil per 1; P < 0·01) but there were no differences between treatments in plasma glucose concentrations following insulin administration.It was concluded that previous body condition can affect contemporary VFI and this effect may be mediated by plasma insulin concentrations providing a long-term feedback signal to the brain. Keywords: body condition, food intake, insulin, sheep.

INHIBITORY EFFECT OF SOMATOSTATIN ON INSULIN SECRETION DURING α-ADRENERGIC BLOCKADE IN THREE DIFFERENT SPECIES

1979 ◽  
Vol 92 (1) ◽  
pp. 166-173 ◽  
Author(s):  
Johannes Järhult ◽  
Bo Ahrén ◽  
Ingmar Lundquist
Keyword(s):  
Insulin Secretion ◽  
B Cell ◽  
Insulin Release ◽  
Plasma Insulin ◽  
Inhibitory Effect ◽  
Insulin Concentration ◽  
Adrenergic Blockade ◽  
Plasma Insulin Concentration ◽  
Basal Plasma ◽  
Stimulation Of

ABSTRACT It has recently been suggested from experiments in dogs that somatostatin suppresses insulin release via a stimulation of the inhibitory α-adrenoceptors of the pancreatic B-cell. The effect of somatostatin on insulin secretion during α-adrenergic blockade with phentolamine was therefore studied in three different species; the rat, the cat and the mouse. It was found that somatostatin significantly depressed insulin release during α-adrenoceptor blockade in all three species. In the rat, infusion of somatostatin at a dose of 0.3 μg/kg/min decreased basal plasma insulin concentration by 92 %. In the presence of phentolamine, the same dose of somatostatin lowered plasma insulin by 85 %. In the cat, a similar infusion of somatostatin lowered basal plasma insulin concentration by 87 %, but its depressive effect during α-adrenergic blockade was comparatively less pronounced (68 %) than in the rat. In the mouse, a single iv injection of somatostatin induced a short-lasting depression of plasma insulin concentration during α-adrenergic blockade. From these results it seems unlikely that somatostatin should inhibit insulin release simply by stimulation of α-adrenoceptors on the B-cell. It cannot be ruled out, however, that a more complex interaction exists between somatostatin and the sympatho-adrenal system with regard to the control of insulin secretion.

ADRENOCORTICOTROPHIN AND THE DEVELOPMENT OF INSULIN SECRETION IN THE RABBIT FOETUS

1975 ◽  
Vol 64 (1) ◽  
pp. 67-75 ◽  
Author(s):  
P. M. B. JACK ◽  
R. D. G. MILNER
Keyword(s):  
Insulin Secretion ◽  
Insulin Release ◽  
Plasma Insulin ◽  
Cell Function ◽  
Pancreatic Tissue ◽  
High Rate ◽  
Insulin Concentration ◽  
Plasma Insulin Concentration ◽  
Β Cell Function

SUMMARY Foetal rabbits were injected with adrenocorticotrophin (ACTH), decapitated, or decapitated and injected simultaneously with ACTH or cortisol in utero on day 24 of gestation. The foetuses were killed after Caesarian section on day 29, and blood was collected for measurement of plasma insulin concentration and pancreatic tissue was obtained for incubation in physiological buffer. Insulin release from the pancreatic tissue of decapitated foetuses was significantly greater than that from the pancreas of control litter-mates when incubated in media containing 3·3 mm-glucose, 16·5 mm-glucose or 16·5 mm-glucose plus 5 μg glucagon/ml, but was similar when the incubation medium contained 3·3 or 16·5 mm-glucose plus 1 mm-theophylline or 3·3 mm-glucose plus 60 mm-potassium. The pancreata of decapitated or intact foetuses injected with ACTH did not differ significantly from control foetuses in terms of insulin release in response to glucose in vitro. The plasma insulin concentration of decapitated foetuses and decapitated foetuses injected with ACTH was raised, whereas that of intact foetuses injected with ACTH was similar to that of the control foetuses. Cortisol injection at the time of decapitation resulted in a high rate of foetal mortality. The results indicate that foetal ACTH or foetal adrenocortical secretion influences the normal development of glucose-mediated insulin secretion in the rabbit and that exogenous ACTH corrects the effect of decapitation on β cell function in vitro but not on plasma insulin concentration.

RADIOIMMUNOASSAY OF INSULIN IN PLASMA AND URINE IN OBESE SUBJECTS AND IN DIABETIC PATIENTS

1969 ◽  
Vol 60 (4) ◽  
pp. 719-736 ◽  
Author(s):  
Kai R. Jorgensen
Keyword(s):  
Glucose Tolerance ◽  
Urinary Excretion ◽  
Plasma Insulin ◽  
Normal Subjects ◽  
Insulin Concentration ◽  
Plasma Insulin Concentration ◽  
Glucose Tolerance Tests ◽  
Obese Subjects ◽  
Fasting Plasma Insulin ◽  
The Mean

ABSTRACT By the use of the double antibody method the immunologically demonstrable insulin, both in the plasma and urine of obese subjects without clinically manifest diabetes and in diabetics who had not been treated with insulin has been determined. In obese subjects without clinically manifest diabetes, hyperinsulinism was found both in the fasting state and during the glucose tolerance tests. In these subjects the 24-hour urinary excretion of insulin was significantly higher than in that of normal subjects. In obese diabetics the mean fasting plasma insulin concentration was found to be significantly higher than in normal subjects, but during oral glucose tolerance tests, despite marked hyperglycaemia, the increase in the mean plasma insulin concentration was only of the same order as in that of normal subjects and had a maximum that was reached later. The 24-hour urinary excretion of insulin in obese diabetics was of the same order as in that of normal subjects. In non-obese diabetics the mean fasting plasma insulin concentration was lower than in normal subjects and lowest in the poorest regulated diabetics with high fasting blood sugar and ketonuria. During glucose tolerance tests it was not possible to demonstrate any increase in the plasma insulin concentration in the non-obese diabetics with ketonuria, while in non-obese diabetics without ketonuria a slight increase in the plasma insulin concentration was found during glucose tolerance tests. The 24-hour urinary excretion of insulin was reduced in relation to the excretion in normal subjects. Thus, the investigations have shown that hyperinsulinism should be regarded as a characteristic of obesity per se, while the clinically manifest diabetes is always connected with hypoinsulinism in relation to body weight.

scholarly journals 146 Nutritional Advances in Fetal and neonatal development: effect of fatty acid supplementation

2020 ◽  
Vol 98 (Supplement_3) ◽  
pp. 121-122
Author(s):  
Alejandro E Relling
Keyword(s):  
Small Intestine ◽  
Fatty Acid ◽  
Plasma Insulin ◽  
Linear Increase ◽  
Late Gestation ◽  
Insulin Concentration ◽  
Plasma Insulin Concentration ◽  
Pufa Supplementation ◽  
Epa And Dha ◽  
Offspring Growth

Abstract Data from a series of experiments demonstrates that maternal supply of polyunsaturated fatty acids, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), during late gestation affects offspring growth. The increase in growth is independent on the fatty acid supplemented during the growing or finishing phase of the offspring; but it is sex dependent. Dam PUFA supplementation increases wether growth. Supplementation with EPA and DHA to pregnant ewes and to their offspring after weaning showed a treatment interaction in mRNA concentration of hypothalamic neuropeptides associated with dry matter intake (DMI) regulation. A dose increased in EPA and DHA in pregnant ewe diets shows a linear increase in growth, but a quadratic change in DMI or feed efficiency; growth was associated with a linear increase in plasma glucose concentration and a linear decrease in plasma ghrelin concentration. In lambs born from ewes supplemented with different sources of FA during a glucose tolerance test; males’ plasma insulin concentration increased as FA unsaturation degree increased in the dam diet, the opposite happened with females’ plasma insulin concentration. Recent data from our lab showed that the supplementation with EPA and DHA during the last third of gestation to pregnant ewes increased liver and small intestine global DNA methylation and small intestine transporters for amino acids in the fetus. Despite EPA and DHA during late gestation increase growth in the offspring; when EPA and DHA were supplemented in early gestation, offspring growth was lesser that lambs born from ewes supplemented a saturated and monounsaturated lipid. The reason for the difference in results it is not clear. However, more studies focusing in some aspect of the biology will help to understand what specific fatty acid needs to be supplemented at different stages of gestation to improve offspring growth.

scholarly journals Fetal growth, glucose tolerance and plasma insulin concentration in rats given a marginal-zinc diet in the latter stages of pregnancy

1988 ◽  
Vol 59 (2) ◽  
pp. 315-322 ◽  
Author(s):  
Susan Southon ◽  
Susan J. Fairweather-Tait ◽  
Christine M. Williams
Keyword(s):  
Blood Glucose ◽  
Glucose Concentration ◽  
Plasma Insulin ◽  
Insulin Concentration ◽  
Oral Glucose ◽  
Fetal Blood ◽  
Plasma Insulin Concentration ◽  
Pregnant Rats ◽  
Zn Content ◽  
Tail Blood

1. Wistar rats were fed on a control semi-synthetic diet throughout pregnancy, or a control diet in the first 2 weeks and a marginal-zinc diet in the 3rd week of pregnancy. On day 20, after an overnight fast, half the animals in each group were given glucose by gavage and the 0–30 min rise in blood glucose measured in tail blood. After 60 min blood was taken by cardiac puncture for glucose and insulin assay. Maternal pancreases were removed and the Zn contents measured. Fetuses from each litter were combined for wet/dry weights, protein and DNA determinations.2. Plasma insulin concentration was higher, and glucose concentration and pancreatic Zn content lower, in pregnantv. non-pregnant animals of similar age, fed on the same diet. Pancreatic Zn content was lowest in the marginal-Zn group of pregnant rats. Fetuses from mothers fed on the marginal-Zn diet during the last week of pregnancy were slightly heavier than controls and had a significantly higher protein: DNA ratio. The 0–30 min rise in blood glucose was significantly greater in the marginal-Zn animals.3. In a second experiment, pregnant rats were given similar diets to those used in the first study, but the marginal-Zn diet was given for a shorter period (days 15–19 of pregnancy). On day 19 the rats were meal-fed and on day 20, after an overnight fast, an oral glucose dose was administered. Tail-blood was taken at timed intervals up to 60 min post-dosing for glucose assay. Both maternal and fetal blood glucose and insulin concentration was measured 70 min post-dosing.4. Values for maternal and fetal blood glucose and plasma insulin, measured 70 min after the administration of a glucose dose, were similar in the two groups, but the initial rise in blood glucose concentration was again significantly higher in pregnant rats given the marginal-Zn diet towards term.5. It is suggested that the change in growth and composition, observed in fetuses from rats given a marginal-Zn diet in later pregnancy, is associated with altered maternal carbohydrate metabolism.

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