The effect of ovarian function on insulin-like growth factor I plasma levels and hepatic IGF-I mRNA levels in diabetic rats treated with insulin

1990 ◽  
Vol 8 (3) ◽  
pp. 235-242 ◽  
Author(s):  
Douglas G. Rogers ◽  
Cecilia T. Valdes ◽  
Karen E. Elkind-Hirsch
Keyword(s):  
Growth Factor ◽  
Plasma Levels ◽  
Ovarian Function ◽  
Diabetic Rats ◽  
Mrna Levels ◽  
Insulin Like Growth Factor ◽  
Factor I ◽  
Igf I ◽  
Growth Factor I

Kidney insulin-like growth factor-I mRNA levels are increased in postpubertal diabetic rats

1991 ◽  
Vol 129 (1) ◽  
pp. 5-10 ◽  
Author(s):  
L. A. Bach ◽  
J. L. Stevenson ◽  
T. J. Allen ◽  
G. Jerums ◽  
A. C. Herington
Keyword(s):  
Growth Factor ◽  
Northern Blotting ◽  
Diabetic Rats ◽  
Mrna Levels ◽  
Insulin Like Growth Factor ◽  
Sprague Dawley ◽  
Factor I ◽  
Igf I ◽  
Renal Enlargement ◽  
Growth Factor I

ABSTRACT Diabetes-associated renal enlargement is more marked in postpubertal than prepubertal rats, and in the postpubertal rat, is associated with increased kidney insulin-like growth factor-I (IGF-I) levels for the first 2 days. In order to determine whether local IGF-I production is the cause of this increase in tissue levels, IGF-I mRNA levels were determined in pre- and postpubertal Sprague–Dawley rats made diabetic with streptozotocin (STZ) and in control rats. RNA was extracted from kidneys and livers of rats at 0 h, 6 h, 12 h and days 1, 2, 3 and 7 after STZ injection. After Northern blotting and hybridization with an oligonucleotide probe complementary to an E domain of the IGF-I cDNA, four distinct bands (7·4, 4·8, 1·8 and 1·0 kb) were found. Densitometric analyses of the most prominent bands (7·4 and 1·0 kb), after normalization for 18S ribosomal RNA content, revealed a 50–100% increase in the kidneys of postpubertal diabetic rats compared with postpubertal controls 12 h after STZ injection (P < 0·05, diabetes vs control). Between days 2 and 7, kidney IGF-I mRNA levels in postpubertal diabetic rats fell to approximately 50% of control levels (P < 0·05, diabetes vs control). In contrast, kidney IGF-I mRNA levels in the prepubertal diabetic rats remained unchanged over the 7 days. Liver IGF-I mRNA levels did not rise during the first 24 h and fell to approximately 60% of control levels by day 7 in both pre- and postpubertal diabetic rats (P < 0·05, diabetes vs control). Increased local IGF-I production may underlie the initiation of renal enlargement associated with diabetes mellitus. Journal of Endocrinology (1991) 129, 5–10

Variation in plasma levels of insulin-like growth factor-I (IGF-I) in lingcod: relationships among season, size, and gonadal steroids

2010 ◽  
Vol 158 (2) ◽  
pp. 439-450 ◽  
Author(s):  
Anne H. Beaudreau ◽  
Kelly S. Andrews ◽  
Donald A. Larsen ◽  
Graham Young ◽  
Brian R. Beckman
Keyword(s):  
Growth Factor ◽  
Plasma Levels ◽  
Gonadal Steroids ◽  
Insulin Like Growth Factor ◽  
Factor I ◽  
Igf I ◽  
Growth Factor I

scholarly journals Insulin-like growth factor I stimulates degradation of an mRNA transcript encoding the 14 kDa ubiquitin-conjugating enzyme

1996 ◽  
Vol 319 (2) ◽  
pp. 455-461 ◽  
Author(s):  
Simon S WING ◽  
Nathalie BEDARD
Keyword(s):  
Skeletal Muscle ◽  
Growth Factor ◽  
Binding Proteins ◽  
Mrna Levels ◽  
Insulin Like Growth Factor ◽  
Mrna Transcript ◽  
Factor I ◽  
Igf I ◽  
Ubiquitin Conjugating Enzyme ◽  
Growth Factor I

Upon fasting, the ubiquitin-dependent proteolytic system is activated in skeletal muscle in parallel with the increases in rates of proteolysis. Levels of mRNA encoding the 14 kDa ubiquitin-conjugating enzyme (E214k), which can catalyse the first irreversible reaction in this pathway, rise and fall in parallel with the rates of proteolysis [Wing and Banville (1994) Am. J. Physiol. 267, E39-E48], indicating that the conjugation of ubiquitin to proteins is a regulated step. To characterize the mechanisms of this regulation, we have examined the effects of insulin, insulin-like growth factor I (IGF-I) and des(1–3) insulin-like growth factor I (DES-IGF-I), which does not bind IGF-binding proteins, on E214k mRNA levels in L6 myotubes. Insulin suppressed levels of E214k mRNA with an IC50 of 4×10-9 M, but had no effects on mRNAs encoding polyubiquitin and proteasome subunits C2 and C8, which, like E214k, also increase in skeletal muscle upon fasting. Reduction of E214k mRNA levels was more sensitive to IGF-I with an IC50 of approx. 5×10-10 M. During the incubation of these cells for 12 h there was significant secretion of IGF-I-binding proteins into the medium. DES-IGF-I, which has markedly reduced affinity for these binding proteins, was found to potently reduce E214k mRNA levels with an IC50 of 3×10-11 M. DES-IGF-I did not alter rates of transcription of the E214k gene, but enhanced the rate of degradation of the 1.2 kb mRNA transcript. The half-life of the 1.2 kb transcript was approximately one-third that of the 1.8 kb transcript and can explain the more marked regulation of this transcript observed previously. This indicates that the additional 3´ non-coding sequence in the 1.8 kb transcript confers stability. These observations suggest that IGF-I is an important regulator of E214k expression and demonstrate, for the first time, stimulation of degradation of a specific mRNA transcript by this hormone, while overall RNA accumulates.

Effects of two oral contraceptives on plasma levels of insulin-like growth factor I (IGF-I) and growth hormone (hGH)

Contraception ◽  
2000 ◽  
Vol 62 (5) ◽  
pp. 259-269 ◽  
Author(s):  
A Balogh ◽  
E Kauf ◽  
R Vollanth ◽  
G Gräser ◽  
G Klinger ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Growth Factor ◽  
Oral Contraceptives ◽  
Plasma Levels ◽  
Insulin Like Growth Factor ◽  
Factor I ◽  
Igf I ◽  
Growth Factor I

scholarly journals Methionine improves the performance and breast muscle growth of broilers with lower hatching weight by altering the expression of genes associated with the insulin-like growth factor-I signalling pathway

2013 ◽  
Vol 111 (2) ◽  
pp. 201-206 ◽  
Author(s):  
Chao Wen ◽  
Ping Wu ◽  
Yueping Chen ◽  
Tian Wang ◽  
Yanmin Zhou
Keyword(s):  
Growth Factor ◽  
Mrna Level ◽  
Muscle Growth ◽  
Breast Muscle ◽  
Broiler Chicks ◽  
Mrna Levels ◽  
Insulin Like Growth Factor ◽  
Factor I ◽  
Igf I ◽  
Growth Factor I

The present study aimed to investigate the responses of broilers with different hatching weights (HW) to dietary methionine (Met). A total of 192 1-d-old Arbor Acres broiler chicks with different HW (heavy: 48·3 (sem 0·1) g and light: 41·7 (sem 0·1) g) were allocated to a 2 (HW) × 2 (Met) factorial arrangement with six replicates of eight chicks. Control starter (1–21 d) and finisher (22–42 d) diets contained 0·50 and 0·43 % Met, respectively. Corresponding values for a high-Met treatment were 0·60 and 0·53 %. Light chicks had poorer (P< 0·05) growth performance and breast muscle weight and lower (P< 0·05) insulin-like growth factor-I (IGF-I) concentration and mRNA level in breast muscle than heavy chicks when both were fed the control diets. High-Met diets improved performance and promoted breast muscle growth and IGF-I concentration in light chicks (P< 0·05). Increased IGF-I and target of rapamycin (TOR) mRNA levels as well as decreased eIF4E-binding protein 1 (4EBP1), atrogin-1 and forkhead box O 4 (FOXO4) mRNA levels were induced by high-Met diets in light chicks (P< 0·05). In conclusion, the Met requirement of broilers might depend on their HW and Met levels used in the control diets in the present study were adequate for heavy chicks but inadequate for light chicks, resulting in poorer performance and breast muscle growth, which were improved by increasing dietary Met supply presumably through alterations in IGF-I synthesis and gene expression of the TOR/4EBP1 and FOXO4/atrogin-1 pathway.

scholarly journals The Measurement of Insulin-Like Growth Factor I: Clinical Applications and Significance

1986 ◽  
Vol 23 (4) ◽  
pp. 413-424 ◽  
Author(s):  
J D Teale ◽  
V Marks
Keyword(s):  
Growth Factor ◽  
Plasma Levels ◽  
Insulin Like Growth Factor ◽  
Gh Therapy ◽  
Assay Sensitivity ◽  
High Molecular Weight Complex ◽  
Factor I ◽  
Normal Plasma ◽  
Igf I ◽  
Growth Factor I

Of the somatomedins so far measured, the selective quantitation of insulin-like growth factor I (IGF-I) appears to have the greatest potential in clinical diagnosis. There have been two approaches to the development of immunoassay systems. One type uses antibodies raised against synthetic fragments of IGF-I which exhibit cross-reactivity with the whole hormone. Such assay systems may be adequate for measuring normal adult plasma IGF-I levels, but the potential for the higher sensitivity required for detecting sub-normal plasma levels in young children is apparent only in methods using antibodies raised against the complete hormone. IGF-I in plasma exists as part of a high molecular weight complex in which it is bound to carrier proteins. The binding proteins may interfere with plasma IGF-I measurements by radioligand assays. Direct analysis of untreated plasma samples is claimed to be possible using disequilibrium assay conditions but in order to maximise assay sensitivity it is necessary to employ an initial extraction stage in order to eliminate binding protein interference. Whether the measurement of plasma IGF-I can or should be used in addition to, or as a replacement for, plasma growth hormone (GH) measurement in the clinical assessment of growth disorders remains a controversial issue. Available evidence indicates that a single, random plasma IGF-I level provides an accurate reflection of GH secretion. Adequate discrimination between the elevated levels in acromegaly and normal reference values has been demonstrated. However, in the investigation of growth-retarded children available radioimmunoassay (RIA) methods have proved only partially successful because of the age-related nature of normal plasma IGF-I concentrations. Existing assays appear capable of identifying sub-normal plasma levels after the age of approximately 4 years. In younger subjects an improvement in assay sensitivity is required in order to establish with greater accuracy the relevant normal ranges. Improvements in the identification of the particular lesion responsible for retarded growth in a child can be achieved by measurement of both plasma GH and IGF-I concentrations. The predictive value of the acute plasma IGF-I response to single-dose GH therapy may identify patients who will respond to long-term GH therapy. Better, more informed decisions on subsequent treatment may therefore be made. Apart from GH control, several other factors influence circulating IGF-I levels. Nutritional status can be assessed through reference to IGF-I analysis, overall catabolic or anabolic processes being associated with decreasing or increasing plasma IGF-I levels respectively.

scholarly journals dl-Methionine supplementation in a low-fishmeal diet affects the TOR/S6K pathway by stimulating ASCT2 amino acid transporter and insulin-like growth factor-I in the dorsal muscle of juvenile cobia (Rachycentron canadum)

2019 ◽  
Vol 122 (07) ◽  
pp. 734-744 ◽  
Author(s):  
Yuanfa He ◽  
Shuyan Chi ◽  
Beiping Tan ◽  
Xiaohui Dong ◽  
Qihui Yang ◽  
...  
Keyword(s):  
Weight Gain ◽  
Amino Acid ◽  
Growth Factor ◽  
Mrna Levels ◽  
Insulin Like Growth Factor ◽  
Rachycentron Canadum ◽  
Dorsal Muscle ◽  
Factor I ◽  
Igf I ◽  
Growth Factor I

AbstractAn 8-week feeding experiment was conducted to investigate the effects of dl-methionine (Met) supplementation in a low-fishmeal diet on growth, key gene expressions of amino acid transporters and target of rapamycin (TOR) pathway in juvenile cobia, Rachycentron canadum. Seven isonitrogenous and isolipidic diets were formulated, containing 0·72, 0·90, 1·00, 1·24, 1·41, 1·63 and 1·86 % Met. Weight gain and specific growth rates increased gradually with Met levels of up to 1·24 % and then decreased gradually. In dorsal muscle, mRNA levels of ASCT2 in the 1·00 % Met group were significantly up-regulated compared with 0·72, 1·63, and 1·86 %. The insulin-like growth factor-I (IGF-I) mRNA levels in the dorsal muscle of fish fed 1·00 and 1·24 % Met were higher than those in fish fed other Met levels. In addition, fish fed 1·24 % Met showed the highest mRNA levels of TOR and phosphorylation of TOR on Ser2448. The phosphorylation of ribosomal p70-S6 kinase (S6K) on Ser371 in the dorsal muscle of fish fed 1·86 % Met was higher than those in the 0·72 % group. In conclusion, straight broken-line analysis of weight gain rate against dietary Met level indicates that the optimal Met requirement for juvenile cobia is 1·24 % (of DM, or 2·71 % dietary protein). Met supplementation in a low-fishmeal diet increased cobia growth via a mechanism that can partly be attributed to Met’s ability to affect the TOR/S6K signalling pathway by enhancing ASCT2 and IGF-I transcription in cobia dorsal muscle.

Insulin-like growth factor I in initial renal hypertrophy in potassium-depleted rats

1992 ◽  
Vol 262 (6) ◽  
pp. F1023-F1031 ◽  
Author(s):  
A. Flyvbjerg ◽  
S. M. Marshall ◽  
J. Frystyk ◽  
R. Rasch ◽  
K. E. Bornfeldt ◽  
...  
Keyword(s):  
Growth Factor ◽  
Body Weight Gain ◽  
Mrna Levels ◽  
Insulin Like Growth Factor ◽  
Renal Hypertrophy ◽  
Factor I ◽  
Collecting Ducts ◽  
Igf I ◽  
Growth Factor I ◽  
K Depletion

We investigated insulin-like growth factor I (IGF-I) in the kidney during the initial renal enlargement induced by dietary K depletion in rats. Kidney weight increase was significant after 3 days of K depletion and amounted to 29% after 7 days compared with pair-fed controls [839 +/- 34 vs. 648 +/- 17 mg (SE), P less than 0.01]. The kidney growth occurred despite almost complete arrest in body weight gain in K-depleted animals (8 +/- 3 vs. 34 +/- 4 g/7 days in controls, P less than 0.01). Whole kidney protein, RNA, and DNA estimations indicated that cellular hypertrophy during the first 4 days was followed by hyperplasia. Immunoassayable kidney IGF-I concentration increased by 106% (673 +/- 30 vs. 327 +/- 14 ng/g, P less than 0.01) in K-depleted animals 24 h after induction of K depletion, stayed elevated until day 4, and returned to control levels on day 7. After K depletion for 24 h, IGF-I immunostaining was markedly increased in the medullary parts of the collecting ducts from K-depleted animals, whereas kidney IGF-I gene expression (IGF-I mRNA) had decreased by 36%. The increase in total kidney IGF-I concentration and immunostainable IGF-I in collecting ducts in kidneys from K-depleted rats precedes the renal hypertrophy and thereby suggests a renotropic role for IGF-I. The increase in kidney IGF-I concentration is not associated with increased IGF-I mRNA levels, indicating that non-transcriptional mechanisms may be responsible for the renal IGF-I accumulation.

scholarly journals Insulin-like growth factor-I and more potent variants restore growth of diabetic rats without inducing all characteristic insulin effects

1993 ◽  
Vol 291 (3) ◽  
pp. 781-786 ◽  
Author(s):  
F M Tomas ◽  
S E Knowles ◽  
P C Owens ◽  
C S Chandler ◽  
G L Francis ◽  
...  
Keyword(s):  
Growth Factor ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Treated Group ◽  
Diabetic Rats ◽  
Insulin Like Growth Factor ◽  
Igf Binding Proteins ◽  
Factor I ◽  
Igf I ◽  
Growth Factor I

The effects of graded doses of insulin-like growth factor-I (IGF-I) and two variants which bind poorly to IGF-binding proteins were investigated in 160 g streptozotocin-induced diabetic rats. The two variants were the truncated form, des(1-3)IGF-I, and another with arginine at residue 3 and an N-terminal extension, termed LR3-IGF-I. The peptides were infused via mini-osmotic pumps. Reference groups received either vehicle or insulin (30 i.u. per day). Treatment led to a marked dose-dependent increase in growth rate and nitrogen balance. The highest dose (695 micrograms/day) of IGF-I increased body weight by 48.1 +/- 1.7 g/7 days, compared with 11.0 +/- 2.8 g/7 days for the vehicle-treated group. The two variants were 2.5-3 times more potent than IGF-I in restoring growth. The insulin-treated group gained more weight (64.5 +/- 1.6 g/7 days), but the added gain was fat (92.5 +/- 4.8 g of fat/kg carcass wet wt., compared with 32.2 +/- 2.1 for all other groups) rather than protein. All peptides increased muscle protein-synthesis rates and RNA levels by up to 50%, with IGF-I the least potent. These high doses of IGFs did not decrease either the glucosuria or the daily excretion rate of N tau-methyl-histidine (N tau-MH). On the other hand, insulin treatment markedly decreased both glucosuria (from 82.7 +/- 5.4 to 4.5 +/- 3.3 mmol/day) and N tau-MH excretion (from 9.3 +/- 0.3 to 7.1 +/- 0.4 mumol/day per kg). This experiment shows that, although IGF-I and variants can restore growth in diabetic rats, other insulin-dependent metabolic processes in liver, muscle and adipose tissue are not restored.

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