scholarly journals Metabolic response of sheep skin to a chronic infusion of a variant of insulin-like growth factor I

1995 ◽  
Vol 308 (2) ◽  
pp. 411-418 ◽  
Author(s):  
J E Hocking Edwards ◽  
S K Khalaf ◽  
B R Sinclaire ◽  
J Lee ◽  
C G Prosser ◽  
...  
Keyword(s):  
Amino Acids ◽  
Growth Factor ◽  
Plasma Concentrations ◽  
Type I ◽  
Insulin Like Growth Factor ◽  
Wool Production ◽  
Factor I ◽  
Igf I ◽  
Wool Follicle ◽  
Growth Factor I

The effects of a chronic (21-day) skin infusion of a variant of insulin-like growth factor I (IGF-I) (long-Arg3-IGF-I; LR3IGF-I) on short-term (48 h) responses of skin metabolism and 21-day plasma hormone concentration, wool-follicle characteristics and wool production were investigated in well-fed castrated Romney sheep. A bilateral arteriovenous preparation was used to infuse LR3IGF-I continuously into the skin on one abdominal flank and saline into the other abdominal flank of six sheep; a further six sheep had one flank infused with saline (controls). LR3IGF-I caused an initial (4-24 h) reduction in the plasma concentrations of amino acids, especially tyrosine, valine and lysine, and, after 24 h, significant (P < 0.05) reductions in blood oxygen and plasma glucose concentrations. After 4 h of LR3IGF-I infusion, there was a significant increase in blood flow (P < 0.05) and oxygen uptake (P < 0.05), and net uptake of amino acids [which was significant (P < 0.05) for valine and phenylalanine] by the LR3IGF-I-infused skin was increased. Total uptake of phenylalanine for skin protein synthesis, measured using [3H]phenylalanine uptake, was also significantly increased after 4 and 24 h of infusion. After 48 h of infusion all LR3IGF-I-dependent measurements of metabolic parameters had fallen to preinfusion values. By day 7 of the 21-day infusion there was a significant (P < 0.05) decrease in circulating endogenous IGF-I in plasma of treated sheep compared with that of control sheep, followed by a significant (P < 0.05) increase between day 7 and 21. Plasma insulin levels followed a similar pattern. There was no change at any stage of infusion in IGF-binding proteins in the plasma of the two LR3IGF-I-infused sheep tested, and it is concluded that LR3IGF-I caused a down-regulation of the type-I IGF-I receptors followed by a rise in endogenous IGF-I concentration consequent on lack of feedback regulation. After 21 days of infusion there was no effect of LR3IGF-I on wool-follicle-bulb-cell mitotic rate, bulb diameter or wool production.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Altered intestinal transport of amino acids in cirrhotic rats: the effect of insulin-like growth factor-I

2000 ◽  
Vol 279 (2) ◽  
pp. G319-G324 ◽  
Author(s):  
Maria Pascual ◽  
Inma Castilla-Cortazar ◽  
Elena Urdaneta ◽  
Jorge Quiroga ◽  
Maria Garcia ◽  
...  
Keyword(s):  
Amino Acids ◽  
Growth Factor ◽  
Glutamic Acid ◽  
Intestinal Transport ◽  
Membrane Vesicles ◽  
Insulin Like Growth Factor ◽  
Anabolic Hormone ◽  
Factor I ◽  
Igf I ◽  
Growth Factor I

The intestine is an important target organ for insulin-like growth factor-I (IGF-I), an anabolic hormone synthesized in the liver upon growth hormone (GH) stimulation. Levels of IGF-I are reduced in cirrhosis, and altered GH/IGF-I axis may contribute to malnutrition in cirrhotic patients. Our aim was to study Na+-dependent jejunal transport of amino acids (l-leucine, l-proline,l-glutamic acid, and l-cysteine) in cirrhotic rats and to analyze the effect of IGF-I on this function. IGF-I or saline was administered for 2 wk to rats with CCl4-induced cirrhosis and saline was administered to healthy control rats. Transport of amino acids was assessed in brush-border membrane vesicles (BBMV) using 14C- or 35S-labeled amino acids, and the kinetic constants V max and K t were determined. Na+-independent uptake of l-leucine, l-proline,l-glutamic acid, and l-cysteine by BBMV was similar in all groups. Na+-dependent uptake of all four amino acids was significantly diminished in cirrhotic rats compared with both controls and IGF-I-treated cirrhotic rats. The latter two groups exhibited similar V max and K t, whereas untreated cirrhotic rats had reduced V max and increased K tcompared with normal controls and IGF-I-treated cirrhotic animals. In conclusion, the transport of all four tested amino acids by BBMV is impaired in cirrhotic rats, and low doses of IGF-I can correct this defect.

Blood Plasma Concentrations of Insulin-like Growth Factor-I (IGF-I) in Resting Standardbred Horses

2002 ◽  
Vol 163 (1) ◽  
pp. 45-50 ◽  
Author(s):  
Z.J. Champion ◽  
B.H. Breier ◽  
W.E. Ewen ◽  
T.T. Tobin ◽  
P.J. Casey
Keyword(s):  
Growth Factor ◽  
Blood Plasma ◽  
Plasma Concentrations ◽  
Insulin Like Growth Factor ◽  
Factor I ◽  
Igf I ◽  
Growth Factor I

scholarly journals Purified hybrid insulin/insulin-like growth factor-I receptors bind insulin-like growth factor-I, but not insulin, with high affinity

1993 ◽  
Vol 290 (2) ◽  
pp. 419-426 ◽  
Author(s):  
M A Soos ◽  
C E Field ◽  
K Siddle
Keyword(s):  
Monoclonal Antibody ◽  
Growth Factor ◽  
Insulin Receptors ◽  
Beta Subunit ◽  
Type I ◽  
Insulin Like Growth Factor ◽  
Factor I ◽  
Igf Receptors ◽  
Igf I ◽  
Growth Factor I

Hybrid insulin/insulin-like growth factor-I (IGF-I) receptors have previously been described in human placenta, but it has not been possible to study their properties in the presence of classical insulin receptors and type I IGF receptors. To facilitate the purification of hybrids, we produced an anti-peptide monoclonal antibody IGFR 1-2, directed against the C-terminal peptide of the type I IGF receptor beta-subunit. The antibody bound native human and rat type I IGF receptors, and reacted specifically with the beta-subunit on immunoblots. Solubilized placental microsomal membranes were depleted of classical type I IGF receptors by incubation with an immobilized monoclonal antibody IGFR 24-55, which reacts well with type I receptors but very poorly with hybrid receptors. Residual hybrid receptors were then isolated by incubation with immobilized antibody IGFR 1-2, and recovered by elution with excess of synthetic peptide antigen. Binding properties of hybrids were compared with those of immuno-affinity-purified insulin receptors and type I IGF receptors, by using the radioligands 125I-IGF-I and 125I-insulin. Hybrids bound approx. 20 times as much 125I-IGF-I as 125I-insulin at tracer concentrations (approx. 0.1 nM). The binding of 125I-insulin, but not 125I-IGF-I, to hybrids increased after treatment with dithiothreitol to reduce disulphide bonds between the alpha-subunits. Hybrids behaved very similarly to type I receptors with respect to the inhibition of 125I-IGF-I binding by unlabelled IGF-I and insulin. By contrast, the affinity of hybrids for insulin was approx. 10-fold lower than that of classical insulin receptors, as assessed by inhibition of 125I-insulin binding by unlabelled hormone. It is concluded that the properties of insulin receptors, but not IGF receptors, are markedly affected by assembly as hybrid compared with classical structures, and that hybrids are more likely to be responsive to IGF-I than insulin under physiological conditions.

scholarly journals Effects of Short-Term Insulin-Like Growth Factor-I (IGF-I) or Growth Hormone (GH) Treatment on Bone Metabolism and on Production of 1,25-Dihydroxycholecalciferol in GH-Deficient Adults1

1998 ◽  
Vol 83 (1) ◽  
pp. 81-87 ◽  
Author(s):  
Tarcisio Bianda ◽  
Yvonne Glatz ◽  
Roger Bouillon ◽  
Ernst Rudolf Froesch ◽  
Christoph Schmid
Keyword(s):  
Growth Hormone ◽  
Growth Factor ◽  
Bone Formation ◽  
Bone Turnover ◽  
Type I ◽  
Insulin Like Growth Factor ◽  
Gh Treatment ◽  
Factor I ◽  
Igf I ◽  
Growth Factor I

Administration of insulin-like growth factor-I (IGF-I) or growth hormone (GH) is known to stimulate bone turnover and kidney function. To investigate the effects of IGF-I and GH on markers of bone turnover, eight adult GH-deficient patients (48 ± 14 yr of age) were treated with IGF-I (5 μg/kg/h in a continuous sc infusion) and GH (0.03 IU/kg/daily sc injection at 2000 h) in a randomized cross-over study. We monitored baseline values for three consecutive days before initiating the five-day treatment period, as well as the wash-out period of ten weeks. Serum osteocalcin, carboxyterminal and aminoterminal propeptide of type I procollagen (PICP and PINP, respectively) increased significantly within 2–3 days of both treatments (P &lt; 0.02) and returned to baseline levels within one week after the treatment end. The changes in resorption markers were less marked as compared with formation markers. Total 1,25-dihydroxycholecalciferol (1,25-(OH)2D3) rose significantly, whereas PTH and calcium levels remained unchanged during either treatment. Conclusions: Because the rapid increase in markers of bone formation was not preceded by an increase in resorption markers, IGF-I is likely to stimulate bone formation by a direct effect on osteoblasts. Moreover, because PTH, calcium, and phosphate remained unchanged, IGF-I appears to stimulate renal 1α-hydroxylase activity in vivo.

Developmental patterns of plasma insulin-like growth factor-I (IGF-I) and body growth in mice from lines divergently selected on the basis of plasma IGF-I

1990 ◽  
Vol 124 (1) ◽  
pp. 151-158 ◽  
Author(s):  
R. A. Siddiqui ◽  
H. T. Blair ◽  
S. N. McCutcheon ◽  
D. D. S. Mackenzie ◽  
P. D. Gluckman ◽  
...  
Keyword(s):  
Body Composition ◽  
Body Weight ◽  
Growth Factor ◽  
Plasma Concentrations ◽  
Body Growth ◽  
Insulin Like Growth Factor ◽  
Developmental Patterns ◽  
Factor I ◽  
Igf I ◽  
Growth Factor I

ABSTRACT A study was conducted to investigate developmental patterns of plasma concentrations of insulin-like growth factor-I (IGF-I), body growth and body composition in mice from lines selected for seven generations on the basis of low (L) or high (H) plasma IGF-I, and in a random-bred control (C) line. Litter size was standardized to eight individuals with equal sex ratios (as far as possible) within 48 h of birth. Pups were weaned at an average of 21 days and separated on the basis of sex. Blood samples were collected from one male and one female of each litter on days, 21, 42, 63 and 105 for analysis of plasma concentrations of IGF-I. The animals were then killed and analysed for water, fat and crude protein content. The plasma concentration of IGF-I was influenced by line (P<0·05) but not by sex. Significant (P< 0·001) differences in liveweight between mice from L and H lines were first evident at 21 days of age. From 28 until 105 days of age the H line was significantly (P< 0·001) heavier than both L and C lines, but differences between C and L lines were inconsistent and mostly non-significant. The growth velocity of the H line was significantly greater than that of C or L lines between 14 and 42 days of age, but differences in growth velocities of C compared with L lines were generally non-significant. Nose–anus length was significantly (P<0·01) affected by sex and line from 42 to 105 days of age, but anus–tail length was not affected by sex or line at any age. Effects of sex and line on empty (digesta-free) body weight and wet weights of carcass and skin plus viscera fractions followed a pattern similar to those of liveweights. The effects of sex and line on protein, water and fat content also paralleled their effects on body size. Differences between males and females, and between the lines, in amount of protein, water and fat could be entirely accounted for by the corresponding differences in body weight. It is concluded from these results that divergent selection on the basis of plasma IGF-I at 42 days of age resulted in lines of animals differing in plasma IGF-I from 21 days of age until maturity. These divergent concentrations of IGF-I are associated with differences between the lines in body growth, particularly during the period of accelerated growth at puberty, but not with changes in body composition. Journal of Endocrinology (1990) 124, 151–158

scholarly journals 21. Plasma concentrations of insulin-like growth factor-I (IGF-I) and resumption of cyclicity in pasture-fed dairy cows

2003 ◽  
Vol 15 (9) ◽  
pp. 21
Author(s):  
F. Y. Obese ◽  
T. E. Moyes ◽  
C. S. Pino ◽  
C. R. Stockdale ◽  
K. L. Macmillan ◽  
...  
Keyword(s):  
Growth Factor ◽  
Dairy Cows ◽  
Plasma Concentrations ◽  
Insulin Like Growth Factor ◽  
Factor I ◽  
Igf I ◽  
Growth Factor I

Insulin-like growth factor I and II in 14 animal species and man as determined by three radioligand assays and two bioassays

1987 ◽  
Vol 114 (1) ◽  
pp. 107-112 ◽  
Author(s):  
Ines Zangger ◽  
Jürgen Zapf ◽  
E. Rudolf Froesch
Keyword(s):  
Growth Factor ◽  
Animal Species ◽  
Mammalian Species ◽  
Cross Reactivity ◽  
Type I ◽  
Insulin Like Growth Factor ◽  
Fat Cell ◽  
Factor I ◽  
Igf I ◽  
Growth Factor I

Abstract. Insulin-like growth factor I and II (IGF I and II) were determined by five different assays in human serum, in the sera of ten mammalian species and in chicken, turtle, and frog serum. Sera of all tested mammals contain two different IGFs corresponding to human immunoreactive IGF I and receptor reactive IGF II. Receptor reactive IGF II of most animal species does not show significant cross-reactivity in the RIA for human IGF II. IGF activity was also detected in sera of non-mammals, such as chicken and turtles, but not in frog serum. The IGF values obtained with the different assay system corresponded rather well: there is a good correlation between the values obtained in the protein binding and the fat cell assay, and between the results of the latter assays and the sum of immunoreactive IGF I and receptor reactive IGF II. The results suggest that those regions in the IGF I and II molecules which are responsible for reactivity with the type I IGF and the insulin receptor have not essentially changed during evolution. Similarly, the C-region, which mainly determines the immunological properties of IGFs, appears to have remained relatively constant in the IGF I, but not in the IGF II molecule.

Effects of Insulin-Like Growth Factor I (IGF-I) on the Porto-Arterial Concentration Differences of Amino Acids and Glucose:

1996 ◽  
Vol 28 (11) ◽  
pp. 582-587 ◽  
Author(s):  
Karin Fhölenhag ◽  
K. Malmlöf ◽  
H. Saxerholt ◽  
G. Klingström ◽  
Anna Skottner ◽  
...  
Keyword(s):  
Amino Acids ◽  
Growth Factor ◽  
Insulin Like Growth Factor ◽  
Factor I ◽  
Arterial Concentration ◽  
Igf I ◽  
Growth Factor I

Influence of nutrition and bovine growth hormone (GH) on hepatic GH binding, insulin-like growth factor-I and growth of lambs

1991 ◽  
Vol 128 (2) ◽  
pp. 181-186 ◽  
Author(s):  
J. J. Bass ◽  
J. M. Oldham ◽  
S. C. Hodgkinson ◽  
P. J. Fowke ◽  
H. Sauerwein ◽  
...  
Keyword(s):  
Body Composition ◽  
Body Weight ◽  
Growth Factor ◽  
Plasma Glucose ◽  
Specific Binding ◽  
Plasma Concentrations ◽  
Insulin Like Growth Factor ◽  
Factor I ◽  
Igf I ◽  
Growth Factor I

ABSTRACT The effect on young lambs of 0·25 mg recombinant bovine GH (bGH)/kg per day on plasma concentrations of insulin-like growth factor-I (IGF-I), glucose, specific hepatic GH binding and body composition changes was examined at two levels of nutrition (lucerne pellets; 3 and 1·7% of body weight/day). Lambs on low levels of nutrition had low plasma IGF-I (P < 0·001). Plasma concentrations of IGF-I were increased by bGH treatment at both levels of nutrition, with the high nutrition group showing the greatest IGF-I response after 3 and 40 days of bGH treatment. Plasma glucose, after 40 days, was higher overall (P < 0·05) in lambs on high nutrition. bGH treatment increased plasma glucose, with the response being greater in the well-fed lambs. Specific binding of GH to liver membranes was highest in lambs on high nutrition and on bGH treatment; no significant interaction between nutrition and bGH treatment was detected, indicating that specific binding of GH was increased proportionally by bGH at both nutritional levels. The major change in body composition was the reduced level of fatness in lambs treated with bGH. There was no significant effect of bGH on body weight although bGH treatment tended to increase weight gain of well-fed lambs and decreased weight loss of poorly nourished lambs. The results show that, although there was a significant (P < 0·05) bGH/nutrition interaction for IGF-I there was no such interaction for body weight/components or specific GH binding to the liver. The results indicate that an increase in plasma IGF-I does not necessarily result in increases in growth or changes in carcass composition. Journal of Endocrinology (1991) 128, 181–186

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