47 ROLE OF INSULIN-LIKE GROWTH FACTOR-I ON THE FUNCTIONAL PARAMETERS AND FERTILITY OF OVINE FROZEN–THAWED SEMEN

2012 ◽  
Vol 24 (1) ◽  
pp. 136
Author(s):  
R. Padilha ◽  
D. Magalhães-Padilha ◽  
M. Cavalcante ◽  
A. Almeida ◽  
M. Gastal ◽  
...  
Keyword(s):  
Growth Factor ◽  
Fluorescence Analysis ◽  
Semen Parameters ◽  
Live Cells ◽  
Insulin Like Growth Factor ◽  
Functional Parameters ◽  
Factor I ◽  
Igf I ◽  
Growth Factor I

The objective of the present experiment was to evaluate the effects of insulin-like growth factor-I (IGF-I) on the viability and fertility of ovine frozen/thawed semen. For evaluating the semen parameters, 5 rams were used. Before cryopreservation, semen samples from each ejaculate were divided into 4 aliquots and extended with Tris+ alone or supplemented with 1 of 3 different concentrations of IGF-I (50, 100 and 250 ng mL–1). Semen was evaluated immediately after thawing (T0), after 1 (T1) and 2 (T2) post-incubation at 37°C. The percentage of morphologically normal spermatozoa and live cells (fluorescence analysis-calcein and ethidium), acrosome integrity (NAR) and motility were analysed and hypoosmotic swelling tests (HOST) were performed to evaluate in vitro sperm survival. This experiment was replicated 5 times. In addition, AI was performed using 121 ewes to compare the optimal concentration of IGF-I versus Tris+ alone on fertility. Data for sperm parameters were analysed by 1-way ANOVA and the differences among groups were examined by Duncan's multiple range test. Pregnancy rates were analysed by the chi-square test of independence. After 1 and 2 h post-incubation, a decrease was observed in all groups in the percentage of motility, NAR and HOST when compared to the semen at T0. The motility rate was higher (P < 0.05) in the IGF-I 100 and IGF-I 250 groups when compared to the IGF-I 50 and Tris+ alone groups (76.2 and 75% vs 66.2 and 64.4%, respectively) at T0, after 1 h (67 and 63.6% vs 57.4 and 56.2%) and 2 h post-incubation (58.2 and 55.4% vs 48 and 47.2%). Furthermore, viability was higher (P < 0.05) in the IGF-I 100 and IGF-I 250 groups than in the IGF-I 50 and Tris+ alone groups (88.7 and 88.3% vs 76.6 and 77.6%, respectively) at T0. There was no difference (P > 0.05) in NAR or HOST among groups. No significant differences (P > 0.05) in fertility were observed between IGF-I 100 and Tris+ groups. In conclusion, the supplementation of Tris extender with IGF-I (100 and 250 ng mL–1) appears to be a successful way to preserve functional parameters of ovine sperm during cryopreservation.

Effects of insulin-like growth factor-I on aromatase cytochrome P450 activity and oestradiol biosynthesis in preimplantation porcine conceptuses in vitro

1991 ◽  
Vol 130 (2) ◽  
pp. 245-250 ◽  
Author(s):  
A. Hofig ◽  
F. A. Simmen ◽  
F. W. Bazer ◽  
R. C. M. Simmen
Keyword(s):  
Growth Factor ◽  
Aromatase Activity ◽  
Insulin Like Growth Factor ◽  
Factor I ◽  
Cytochrome P450 Activity ◽  
Igf I ◽  
Growth Factor I ◽  
Oestradiol Production ◽  
P450 Activity

ABSTRACT The effects of insulin-like growth factor-I (IGF-I) on aromatase P450 activity and steroid production in preimplantation pig conceptuses were evaluated in vitro. Conceptuses recovered from gilts on days 10 and 12 of pregnancy were incubated for 6 h in modified Eagle's Minimum Essential Medium (MEM) plus IGF-I (0·1 μg/ml) or insulin (8·5 μg/ml), and conceptuses were monitored for their ability to convert [1,2-3H]β-testosterone into oestrogens. Aromatase activity of day-10 conceptuses was low and unaffected by IGF-I or insulin. In contrast, basal aromatase activity in day-12 conceptuses was about threefold higher and was further increased by IGF-I (P < 0·02), but was unaffected by insulin. To determine whether higher aromatase P450 activity was associated with increased oestradiol production, concentrations of oestradiol were determined by radioimmunoassay in culture medium of day-11 and -12 conceptuses, after incubation in MEM alone or in the presence of dehydroepiandrosterone (DHA, 1 μg/ml) with or without IGF-I (0·1 μg/ml) or insulin (0·1 or 8·5 μg/ml) for 24 h. Conceptuses in MEM plus DHA produced more oestradiol (P < 0·01) than those in MEM alone. Addition of IGF-I or insulin did not increase the effect of DHA. Basal oestradiol production was dependent on conceptus size; however, IGF-I or insulin did not affect basal or DHA-stimulated oestradiol production regardless of conceptus size. These findings demonstrate that IGF-I can modulate aromatase activity in vitro, without affecting overall de-novo steroidogenesis. Thus, the developmental increase in conceptus oestradiol production observed during early pregnancy in the pig may reflect synergistic interactions between IGF-I and other regulatory factors present within the conceptus and/or uterine environment. Journal of Endocrinology (1991) 130, 245–250

Insulin and growth hormone act synergistically to stimulate insulin-like growth factor-I production by cultured chicken hepatocytes

1991 ◽  
Vol 128 (3) ◽  
pp. 389-393 ◽  
Author(s):  
B. Houston ◽  
I. E. O'Neill
Keyword(s):  
Growth Factor ◽  
Insulin Like Growth Factor ◽  
Free Medium ◽  
In Vitro System ◽  
Factor I ◽  
Maximal Stimulation ◽  
Igf I ◽  
Growth Factor I ◽  
Stimulation Of

ABSTRACT Cultured chicken hepatocytes were used to investigate whether insulin and GH interact to regulate insulin-like growth factor-I (IGF-I) production in vitro. In the first set of experiments hepatocytes were preincubated for 6 h in hormone-free medium, and the effects of various combinations of insulin and GH on IGF-I production over the next 24 h were quantified by radioimmunoassay. Basal IGF-I production was 5·36 pg IGF-I/μg DNA and this was increased 1·31±0·13-fold (mean ± s.e.m.) by insulin, 1·90±0·24-fold by GH and 4·46±0·68-fold by a combination of insulin and GH. These results demonstrate that insulin and GH interact synergistically to stimulate IGF-I production in vitro. The synergism with GH occurred at physiological concentrations of insulin with half-maximal stimulation occurring at an insulin concentration of 6 ng/ml. In hepatocytes which had been exposed to insulin immediately before the start of the experiment, the presence of insulin was no longer required for maximal stimulation of IGF-I production by GH. This in-vitro system will facilitate the study of the molecular basis of the interaction between insulin and GH. Journal of Endocrinology (1991) 128, 389–393

A combination of insulin-like growth factor I (IGF-I) and FSH promotes proliferation of prepubertal bovine Sertoli cells isolated and cultured in vitro

2017 ◽  
Vol 29 (8) ◽  
pp. 1635 ◽  
Author(s):  
A. Dance ◽  
J. Kastelic ◽  
J. Thundathil
Keyword(s):  
Growth Factor ◽  
Sertoli Cell ◽  
Sertoli Cells ◽  
Seminiferous Tubules ◽  
Insulin Like Growth Factor ◽  
Factor I ◽  
Bull Calves ◽  
Igf I ◽  
Growth Factor I

Beef and dairy bull calves fed a low-nutrition diet during early life had decreased concentrations of circulating insulin-like growth factor I (IGF-I), delayed increases in testosterone, smaller testes and delayed puberty compared with those fed high-nutrition diets. Although IGF-1 has important roles in Sertoli cell function in rats and mice, this has not been well documented in bulls. The objectives of this study were to: (1) isolate Sertoli cells from bull calves at 8 weeks of age, (2) culture them in vitro and (3) determine the effects of IGF-I, FSH and a combination of both hormones on cell proliferation. For Sertoli cell isolation, minced testicular tissues were treated with collagenase followed by trypsin and hyaluronidase to digest seminiferous tubules and release Sertoli cells. In this study, Sertoli cells were successfully isolated from 8-week-old Holstein bull calves (n = 4) and these cells were cultured for up to 8 days. A combination of IGF-I and FSH increased proliferation (~18%) and therefore cell number (1.5-fold) of prepubertal bovine Sertoli cells in culture, providing clear evidence that IGF-I has a similar role in bovine Sertoli cells as reported in rodents.

Production of insulin-like growth factor I (IGF-I) and IGF-binding proteins by rat intestinal stromal cells in vitro

1998 ◽  
Vol 54 (2) ◽  
pp. 158-166
Author(s):  
R. G. MacDonald ◽  
R. H. McCusker ◽  
D. J. Blackwood ◽  
J. A. Vanderhoof ◽  
J. H. Y. Park
Keyword(s):  
Growth Factor ◽  
Stromal Cells ◽  
Binding Proteins ◽  
Insulin Like Growth Factor ◽  
Igf Binding Proteins ◽  
Factor I ◽  
Igf I ◽  
Igf Binding ◽  
Growth Factor I

Effects of insulin-like growth factor-I and insulin on the in-vitro uptake of sulphate by eel branchial cartilage: evidence for the presence of independent hepatic and pancreatic sulphation factors

1992 ◽  
Vol 133 (2) ◽  
pp. 211-219 ◽  
Author(s):  
C. Duan ◽  
T. Hirano
Keyword(s):  
Growth Factor ◽  
Coho Salmon ◽  
Bovine Insulin ◽  
Dependent Manner ◽  
Insulin Like Growth Factor ◽  
Cartilage Growth ◽  
Factor I ◽  
Igf I ◽  
Growth Factor I

ABSTRACT The possible roles of insulin-like growth factor-I (IGF-I) and insulin in regulating cartilage growth were studied in the teleost Anguilla japonica. Significant sulphation activity was found in the extracts of pancreas, liver and muscle, but not in those of kidney, intestine or spleen. The hepatic sulphation activity was significantly decreased by hypophysectomy or by fasting for 14 days, suggesting that this activity is regulated by pituitary function and nutritional status. Northern blot analysis revealed that the hepatic IGF-I mRNA in the eel consists of a major 4·0 kb band. This mRNA was GH-dependent and was significantly decreased by fasting for 14 days. On the other hand, fasting for 14 days had no significant effect on pancreatic sulphation activity. Pancreatic extracts from both intact and hypophysectomized eels exhibited equally significant stimulating activity. Addition of bovine or human insulin (1–250 ng/ml) to the culture medium significantly stimulated sulphate uptake in a dose-dependent manner. Teleost (coho salmon) insulin was as effective as bovine insulin. Bovine insulin was more effective than IGF-I at lower concentrations (1–4 ng/ml) but less effective at higher concentrations (10–250 ng/ml). These results indicate that not only IGF-I but also insulin are likely to be involved in the regulation of cartilage growth in the eel. Journal of Endocrinology (1992) 133, 211–219

scholarly journals Viral expression of insulin-like growth factor I E-peptides increases skeletal muscle mass but at the expense of strength

2014 ◽  
Vol 306 (8) ◽  
pp. E965-E974 ◽  
Author(s):  
Becky K. Brisson ◽  
Janelle Spinazzola ◽  
SooHyun Park ◽  
Elisabeth R. Barton
Keyword(s):  
Skeletal Muscle ◽  
Cell Proliferation ◽  
Growth Factor ◽  
Muscle Mass ◽  
Insulin Like Growth Factor ◽  
Factor I ◽  
Igf I ◽  
Growth Factor I

Insulin-like growth factor I (IGF-I) is a protein that regulates and promotes growth in skeletal muscle. The IGF-I precursor polypeptide contains a COOH-terminal extension called the E-peptide. Alternative splicing in the rodent produces two isoforms, IA and IB, where the mature IGF-I in both isoforms is identical yet the E-peptides, EA and EB, share less than 50% homology. Recent in vitro studies show that the E-peptides can enhance IGF-I signaling, leading to increased myoblast cell proliferation and migration. To determine the significance of these actions in vivo and to evaluate if they are physiologically beneficial, EA and EB were expressed in murine skeletal muscle via viral vectors. The viral constructs ensured production of E-peptides without the influence of additional IGF-I through an inactivating mutation in mature IGF-I. E-peptide expression altered ERK1/2 and Akt phosphorylation and increased satellite cell proliferation. EB expression resulted in significant muscle hypertrophy that was IGF-I receptor dependent. However, the increased mass was associated with a loss of muscle strength. EA and EB have similar effects in skeletal muscle signaling and on satellite cells, but EB is more potent at increasing muscle mass. Although sustained EB expression may drive hypertrophy, there are significant physiological consequences for muscle.

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