+ Site Statistics
+ Search Articles
+ Subscribe to Site Feeds
EurekaMag Most Shared ContentMost Shared
EurekaMag PDF Full Text ContentPDF Full Text
+ PDF Full Text
Request PDF Full TextRequest PDF Full Text
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter
Follow on Google+Follow on Google+
Follow on LinkedInFollow on LinkedIn

+ Translate

Regulation of plasma and tissue levels of insulin-like growth factor-I by nutrition and treatment with growth hormone in sheep

Journal of Endocrinology 136(2): 217-224
Regulation of plasma and tissue levels of insulin-like growth factor-I by nutrition and treatment with growth hormone in sheep
Tissue and plasma levels of insulin-like growth factor-I (IGF-I), and relative levels of liver IGF-I RNA, were measured in 6-month-old ewe lambs which were well fed (n=10) or starved (n=10) for 5 days. Half of each nutrition group was given daily (09.00 h) injections of human GH (hGH; 0.15 mg/kg body weight per day). Blood was sampled daily from 09.00 to 12.00 h at 15-min intervals through jugular vein catheters and the lambs were slaughtered 24 h after the fifth injection of hGH. Tissue and plasma IGF-I was extracted using an acid-ethanol-cryo-precipitation technique and estimated by radioimmunoassay. Tissue IGF-I was corrected for retained plasma IGF-I using tissue and blood haemoglobin levels. Liver IGF-I RNA levels were monitored by in-situ hybridization. Plasma IGF-I (nmol/l) was higher in both the fed group and the fed group given GH treatment. Tissue IGF-I from kidneys (nmol/kg) was also higher (P lt 0.001) in the fed group. There was no significant difference in IGF-I concentrations in the muscle biceps femoris or liver between fed and starved lambs. Although GH treatment did not increase IGF-I levels in tissues significantly, IGF-IRNA levels in liver were increased (P=0.02) in both fed and starved animals. The relative liver IGF-I RNA levels positively correlated with their corresponding tissue IGF-I levels in the fed group and the fed group given GH treatment. The lack of a significant IGF-I response to GH in tissues may be due to either the time at which tissues were sampled after the GH treatment or the dose of GH administered. However, the higher IGF-I concentrations in plasma and kidney from fed compared with starved animals and the positive correlations between liver IGF-I and IGF-I RNA levels suggest that tissue and plasma IGF-I is regulated by nutrition and GH, with nutrition playing a critical role in the regulation of tissue and plasma IGF-I in normal lambs.

(PDF same-day service: $19.90)

Accession: 002477233

PMID: 7681465

DOI: 10.1677/joe.0.1360217

Related references

Differential regulation of plasma levels of insulin-like growth factors-I and -II by nutrition, age and growth hormone treatment in sheep. Journal of Endocrinology 147(3): 507-516, 1995

Adult growth hormone deficiency treatment with a combination of growth hormone and insulin-like growth factor-1 resulting in elevated sustainable insulin-like growth factor-1 and insulin-like growth factor binding protein 3 plasma levels: a case report. Journal of Medical Case Reports 4(): 305-305, 2010

Endocrine growth regulation of adult Atlantic salmon in seawater: The effects of light regime on plasma growth hormone, insulin-like growth factor-I, and insulin levels. Aquaculture 250(3-4): 862-871, 2005

(I) Early changes in plasma insulin and growth hormone levels after feeding in lambs and adult sheep. (II) Diurnal patterns of plasma insulin, growth hormone, corticosteroid and metabolite concentrations in fed and fasted sheep. Australian Journal of Biological Sciences 27(2): 157-166, 167-181, 1974

Developmental regulation of insulin like growth factor i and ii igf i and ii messenger rna plasma igf i insulin and growth hormone in sheep. Journal of Animal Science 69(SUPPL 1): 288, 1991

Regulation of rat white adipose tissue insulin like growth factor 1 gene expression by growth hormone and nutrition. FASEB Journal 4(4): A916, 1990

Effect of growth hormone treatment on the distribution of insulin-like growth factor-I between plasma and lymph of lactating sheep. Journal of Endocrinology 132(3): 339-344, 1992

Neuroendocrine control of growth hormone release in sheep effect of dose and route of administration of growth hormone releasing factor on plasma growth hormone levels. Proceedings of the New Zealand Society of Animal Production 50: 101-104, 1990

Differential regulation of transcription initiation from insulin-like growth factor-I (IGF-I) leader exons and of tissue IGF-I expression in response to changed growth hormone and nutritional status in sheep. Endocrinology 132(4): 1797-1807, 1993

Effect of thyroxine replacement therapy on plasma insulin-like growth factor 1 levels and growth hormone responses to growth hormone releasing factor in hypothyroid patients. Clinical Endocrinology 27(1): 85-90, 1987