scholarly journals Changes in rates of glucose utilization and regulation of glucose disposal by fast-twitch skeletal muscles in late pregnancy

1993 ◽  
Vol 292 (2) ◽  
pp. 431-438 ◽  
Author(s):  
M J Holness ◽  
M C Sugden

Glucose utilization indices (GUI) were measured in vivo in conjunction with active pyruvate dehydrogenase complex (PDH(a) and glycogen synthase (GS) activities in fast-twitch skeletal muscles [extensor digitorum longus (EDL), tibialis anterior and gastrocnemius] of late-pregnant rats and age-matched virgin control rats in the fed state, after 24 h starvation and at 2 h after re-feeding with standard laboratory chow ad libitum after 24 h starvation. As demonstrated previously [Holness and Sugden (1990) Biochem. J 277, 429-433], GUI values of fast-twitch skeletal muscles of virgin rats were low in the fed ad libitum and the 24 h-starved states, but dramatically increased after subsequent chow re-feeding. GUI values of fast-twitch skeletal muscles of late-pregnant rats were also low in the fed and starved states and were increased by re-feeding, but the increase in GUI values elicited by re-feeding was greatly attenuated. PDHa activities in EDL, tibialis anterior and gastrocnemius in the fed state were unaffected by late pregnancy, and skeletal-muscle PDHa activities were decreased after 24 h of starvation in both groups. Whereas re-feeding of virgin rats with standard diet for 2 h restored PDHa activities in fast-twitch skeletal muscles to values for rats continuously fed ad libitum, PDHa activities in fast-twitch skeletal muscles of late-pregnant rats, although increased in response to re-feeding, remained considerably less than the corresponding fed ad libitum values after 2 h of re-feeding. In contrast, neither skeletal-muscle GS re-activation nor rates of skeletal-muscle glycogen deposition after re-feeding were markedly affected by late pregnancy. The results are discussed in relation to the specific targeting of individual pathways of glucose disposal in fast-twitch skeletal muscles during re-feeding in late pregnancy.

1995 ◽  
Vol 269 (5) ◽  
pp. E858-E863 ◽  
Author(s):  
P. Ramos ◽  
E. Herrera

To determine whether sustained exaggerated hyperinsulinemia in normoglycemic rats modifies insulin responsiveness during pregnancy, 17-day-pregnant and virgin rats were studied after receiving a continuous intravenous infusion (35 ml/day) of either 50% glucose or bidistilled water (controls) for 72 h. Plasma glucose was unchanged, whereas insulin was highly increased, and the effect was more marked in pregnant than in virgin rats. Insulin responsiveness, estimated under the hyperinsulinemic euglycemic clamp with 0.8 IU insulin.h-1.kg-1, was lower in control pregnant than in virgin rats but higher in pregnant than in virgin rats in those that had received the glucose infusion. The tissue glucose utilization metabolic index (GUI) was estimated with 2-deoxy-D-[1-3H]glucose in the clamped rats. The GUI was lower in heart, white- and red-fiber skeletal muscle, and adipose tissue in control pregnant rats than in control virgin rats, and, although the glucose infusion decreased that index in both red-fiber muscle and adipose tissue in virgin rats, glucose increased the index in red-fiber muscle in pregnant rats to the level found in virgin controls. Results therefore show that, when unaccompanied by hypoglycemia, sustained exaggerated hyperinsulinemia decreases insulin responsiveness in virgin rats but reverts insulin resistance in late-pregnant rats.


1992 ◽  
Vol 286 (2) ◽  
pp. 395-398 ◽  
Author(s):  
M J Holness ◽  
R M Howard ◽  
M C Sugden

We measured glucose utilization index (GUI) values in individual skeletal muscles of conscious rats during the light (quiescent) and dark (feeding/activity) phases. There was a 2-3-fold variation in muscle GUI values, with peak values observed at the end of the dark phase and minimum values observed at 6-9 h into the light phase. GUI values in working muscles (soleus and adductor longus) were consistently higher than in non-working muscles (tibialis anterior and extensor digitorum longus), indicating that working muscles make the major contribution of the total skeletal muscle mass to glucose disposal during unrestricted feeding. There was a clear overall increase in muscle glycogen deposition during the first 9 h of the dark phase; this was concomitant with an increase in food consumption. Peak glycogen concentrations were reached after 9 h of darkness, but subsequently declined. The pattern of changes in muscle GUI values during the light and dark phases is discussed in relation to the role of insulin in facilitating glucose clearance.


1991 ◽  
Vol 277 (2) ◽  
pp. 429-433 ◽  
Author(s):  
M J Holness ◽  
M C Sugden

We investigated the extent to which increases in glucose utilization indices (GUIs) in individual skeletal muscles during chow re-feeding after 6 h, 24 h or 48 h starvation are related to the antecedent duration of starvation. Chow re-feeding after either acute or prolonged starvation led to an increase in glucose disposal by the muscle mass. Glucose intolerance after prolonged starvation was not associated with lower values of GUI in skeletal muscle. In both working and non-working muscles, the increment in GUI during the first 2 h of re-feeding was less after acute than after prolonged starvation. In non-working muscles the differential responses to re-feeding were due to higher GUI values after re-feeding rather than lower pre-prandial GUI values. Therefore the contribution of non-working muscles to glucose clearance is higher as the antecedent period of starvation is extended. Rates of glycogen deposition in non-working muscles after refeeding were similar to absolute values of GUI, and a strong relationship existed between measured GUI values and rates of glycogen deposition.


1990 ◽  
Vol 271 (2) ◽  
pp. 421-425 ◽  
Author(s):  
M C Sugden ◽  
Y L Liu ◽  
M J Holness

In the fed state, hyperthyroidism increased glucose utilization indices (GUIs) of skeletal muscles containing a lower proportion of oxidative fibres. Glycogen concentrations were unchanged, but active pyruvate dehydrogenase (PDHa) activities were decreased. Hyperthyroidism attenuated the effects of 48 h of starvation to decrease muscle GUI. Glycogen concentrations and PDHa activities after 48 h of starvation were low and similar in euthyroid and hyperthyroid rats. The increase in glucose uptake and phosphorylation relative to oxidation and storage in skeletal muscle induced by hyperthyroidism may contribute to increased glucose re-cycling in the fed hyperthyroid state and to glucose turnover in the starved hyperthyroid state.


1996 ◽  
Vol 271 (6) ◽  
pp. E1061-E1066 ◽  
Author(s):  
D. Meynial-Denis ◽  
M. Mignon ◽  
A. Miri ◽  
J. Imbert ◽  
E. Aurousseau ◽  
...  

Glutamine synthetase (GS) is a glucocorticoid-inducible enzyme that has a key role for glutamine synthesis in muscle. We hypothesized that the glucocorticoid induction of GS could be altered in aged rats, because alterations in the responsiveness of some genes to glucocorticoids were reported in aging. We compared the glucocorticoid-induced GS in fast-twitch and slow-twitch skeletal muscles (tibialis anterior and soleus, respectively) and heart from adult (age 6-8 mo) and aged (age 22 mo) female rats. All animals received dexamethasone (Dex) in their drinking water (0.77 +/- 0.10 and 0.80 +/- 0.08 mg/day per adult and aged rat, respectively) for 5 days. Dex caused an increase in both GS activity and GS mRNA in fast-twitch and slow-twitch skeletal muscles from adult and aged rats. In contrast, Dex increased GS activity in heart of adult rats, without any concomitant change in GS mRNA levels. Furthermore, Dex did not affect GS activity in aged heart. Thus the responsiveness of GS to an excess of glucocorticoids is preserved in skeletal muscle but not in heart from aged animals.


2000 ◽  
Vol 278 (6) ◽  
pp. E1067-E1077 ◽  
Author(s):  
Arend Bonen ◽  
Dragana Miskovic ◽  
Mio Tonouchi ◽  
Kathleen Lemieux ◽  
Marieangela C. Wilson ◽  
...  

The expression of two monocarboxylate transporters (MCTs) was examined in muscle and heart. MCT1 and MCT4 proteins are coexpressed in rat skeletal muscles, but only MCT1 is expressed in rat hearts. Among six rat fast-twitch muscles (red and white gastrocnemius, plantaris, extensor digitorum longus, red and white tibialis anterior) there was an inverse relationship between MCT1 and MCT4 ( r = −0.94). MCT1 protein was correlated with MCT1 mRNA ( r = 0.94). There was no relationship between MCT4 mRNA and MCT4 protein. MCT1 ( r = −0.97) and MCT4 ( r = 0.88) protein contents were correlated with percent fast-twitch glycolytic fiber. When normalized for their mRNAs, MCT1 but not MCT4 was still correlated with the percent fast-twitch glycolytic fiber composition of rat muscles ( r = −0.98). MCT1 and MCT4 were also measured in plasma membranes (PM), triads (TR), T tubules (TT), sarcoplasmic reticulum (SR), and intracellular membranes (IM). There was an intracellular pool of MCT4 but not of MCT1. The MCT1 subcellular distribution was as follows: PM (100%) > TR (31.6%) > SR (15%) = TT (14%) > IM (1.7%). The MCT4 subcellular distribution was considerably different [PM (100%) > TR (66.5%) > TT (36%) = SR (43%) > IM (24%)]. These studies have shown that 1) the mechanisms regulating the expression of MCT1 (transcriptional and posttranscriptional) and MCT4 (posttranscriptional) are different and 2) differences in MCT1 and MCT4 expression among muscles, as well as in their subcellular locations, suggest that they may have different roles in muscle.


1964 ◽  
Vol 206 (4) ◽  
pp. 796-804 ◽  
Author(s):  
Robert O. Scow ◽  
Sidney S. Chernick ◽  
Marlene S. Brinley

Pregnant rats fasted on the 18th or 19th day of gestation developed hypoglycemia, severe ketosis, and hyperlipemia. The latter, which consisted primarily of triglycerides, was accompanied by increased plasma free fatty acids and accumulation of fat in the liver and kidneys. The effects of fasting were diminished by starting the fast earlier in pregnancy or by hysterectomy. Both ketosis and hyperlipemia were corrected by administration of insulin, tolbutamide, or glucose. The findings indicate that increased fat mobilization and ketosis in fasting pregnant rats are the result of insulin lack. It is suggested that the high priority of the fetuses for glucose reduced the maternal blood glucose concentration to a level too low to stimulate insulin secretion during fasting. Fasting did not alter the rapid growth of the fetuses. Pregnant rats fed ad libitum also developed hypertriglyceridemia if the diet contained fat. This hyperlipemia, unlike that in the fasted rats, was not due to increased fat mobilization and was unaffected by insulin administration. It is concluded that the fractional clearance of blood triglycerides is greatly reduced during late pregnancy.


1990 ◽  
Vol 272 (1) ◽  
pp. 133-137 ◽  
Author(s):  
M C Sugden ◽  
Y L Liu ◽  
M J Holness

Glucose utilization indices (GUI) increased to fed values in diaphragm and oxidative skeletal muscles and exceeded fed values in non-oxidative muscles within 2 h of re-feeding chow to 48 h-starved rats. Cardiac GUI reached fed values only after 7 h. Glycogen deposition accounted for most of the glucose phosphorylated in skeletal muscle over the first 2 h in oxidative muscles and over the first 4 h in non-oxidative muscles. In oxidative muscles, the contribution of glycogen deposition to total glucose 6-phosphate disposal diminished as re-feeding was extended from 2 to 6 h.


2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Nasser M Rizk ◽  
Amina Saleh ◽  
Abdelrahman ElGamal ◽  
Dina Elsayegh ◽  
Isin Cakir ◽  
...  

Abstract The Expression of TBC1 Domain Family, member 4 (TBC1D4) in Skeletal Muscles of Insulin-Resistant Mice in Response to Sulforaphane. Background: Obesity is commonly accompanied by impaired glucose homeostasis. Decreased glucose transport to the peripheral tissues, mainly skeletal muscle, leads to reduced total glucose disposal and hyperglycemia. TBC1D4 gene is involved in the trafficking of GLUT4 to the outer cell membrane in skeletal muscle. Sulforaphane (SFN) has been suggested as a new potential anti-diabetic compound acting by reducing blood glucose levels through mechanisms not fully understood (1). The aim of this study is to investigate the effects SFN on TBC1D4 and GLUT4 gene expression in skeletal muscles of DIO mice, in order to elucidate the mechanism(s) through which SFN improves glucose homeostasis. Methodology: C57BL/6 mice (n=20) were fed with a high fat diet (60%) for 16 weeks to generate diet induced obese (DIO) mice with body weights between 45–50 gm. Thereafter, DIO mice received either SFN (5mg/kg BW) (n=10) or vehicle (n=10) as controls daily by intraperitoneal injections for four weeks. Glucose tolerance test (1g/kg BW, IP) and insulin sensitivity test (ITT) were conducted (1 IU insulin/ g BW, IP route) at the beginning and end of the third week of the injection. At the end of 4 weeks of the injection, samples of blood and skeletal muscles of both hindlimbs were collected. The expression levels of GLUT4 and TBC1D4 genes were analyzed by qRT-PCR. Blood was also used for glucose, adiponectin and insulin measurements. Results: SFN-treated DIO mice had significantly lower non-fasting blood glucose levels than vehicle-treated mice (194.16 ± 14.12 vs. 147.44 ± 20.31 mg/dL, vehicle vs. SFN, p value=0.0003). Furthermore, GTT results indicate that the blood glucose levels at 120 minutes after glucose infusion in was (199.83±34.53 mg/dl vs. 138.55±221.78 mg/dl) for vehicle vs. SFN with p=0.0011 respectively. ITT showed that SFN treatment did not enhance insulin sensitivity in DIO mice. Additionally, SFN treatment did not significantly change the expression of TBC1D4, and GLUT4 genes in skeletal muscles compared to vehicle treatment (p values >0.05). Furthermore, SFN treatment did not significantly affect the systemic insulin (1.84±0.74 vs 1.54±0.55 ng/ml, p=0.436), or adiponectin (11.96 ±2.29 vs 14.4±3.33 ug/ml, p=0.551) levels in SFN vs. vehicle-treated DIO mice, respectively. Conclusion: SFN treatment improves glucose disposal in DIO mice, which is not linked to the gene expression of GLUT4 and TBC1D4 and its mechanism of glucose disposal in skeletal muscles. Furthermore, SFN treatment did not improve insulin level, and the insulin sensitizer hormone adiponectin as potential players for enhancing insulin sensitivity. 1. Axelsson AS, Tubbs E, Mecham B, Chacko S, Nenonen HA, Tang Y, et al. Sci Transl Med. 2017;9(394).


1987 ◽  
Vol 253 (1) ◽  
pp. E33-E39 ◽  
Author(s):  
K. Meszaros ◽  
G. J. Bagby ◽  
C. H. Lang ◽  
J. J. Spitzer

Glucose metabolism of respiratory and nonrespiratory muscles of different fiber composition was investigated in conscious rats. The accumulation of phosphorylated 2-deoxyglucose (2DGP) was increased in skeletal muscles by 56-102% and in diaphragm by 236% at 3 h after treatment with 100 micrograms/100 g endotoxin. The increase was still marked at 24 h, whereas it diminished at 48 h in the diaphragm, abdominal muscle, and white portion of the quadriceps. In the red portion of this muscle 2DGP accumulation was less than that in time-matched controls at 24 and 48 h. Whole gastrocnemius (mixed-fiber types) showed no changes after 24 h. The high 2DGP accumulation in brain remained stable. The retention of 2DGP in tissues, studied by sequential double labeling, did not change 3 h after endotoxin. The lumped constant was similar in the isolated epitrochlear muscles of endotoxemic and control rats. Whole-body glucose utilization (Rd) was increased by 68% 3 h after endotoxin, but it was normal at 24 and 48 h. The increase of glucose utilization by the entire skeletal muscle mass was responsible for approximately 25% of the increase in Rd; therefore it appears that other tissues also contributed significantly to the endotoxin-induced alterations in carbohydrate metabolism.


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