Regulation of porcine insulin-like growth factor I and growth hormone receptor mRNA expression by energy status

Weller, P. A.; Dauncey, M. J.; Bates, P. C.; Brameld, J. M.; Buttery, P. J.; Gilmour, R. S.

Abstract

Regulation of insulin-like growth factor I (IGF-I) and growth hormone (GH) receptor mRNA in liver and muscle by energy status was assessed in 2-mo-old pigs by altering thermoregulatory demand and energy intake over a 5-wk period to produce a range of plasma IGF-I concentrations from 3.5 ± 0.7 to 28.9 ± 6.2 nmol/l. These values were related directly to growth rates (0.06 ± 0.02 to 0.44 ± 0.01 kg/day) and total hepatic IGF-I mRNA levels. Increased growth rates were accompanied by an increase in hepatic class 1 and class 2 IGF-I mRNA levels and an increase in the ratio of class 2 to class 1 IGF-I mRNA in liver, suggesting a distinct role for class 2 expression in the endocrine growth response. High levels of class 1 transcripts and a virtual absence of class 2 transcripts characterized all muscle tissues examined, and there was no correlation with plasma IGF-I levels. This suggests that growth promotion in response to increased energy status is regulated via endocrine hepatic IGF-I rather than via a paracrine response. The levels of GH receptor mRNA were positively correlated with overall growth rate (P < 0.005) in liver and negatively correlated (P < 0.05) in muscle, indicating distinct tissue- specific effects of energy status.

Citation

Weller, P. A., Dauncey, M. J., Bates, P. C., Brameld, J. M., Buttery, P. J., & Gilmour, R. S. (1994). Regulation of porcine insulin-like growth factor I and growth hormone receptor mRNA expression by energy status. AJP - Endocrinology and Metabolism, 266(5), E776-E785. https://doi.org/10.1152/ajpendo.1994.266.5.E776

• Journal Article Type: Article
• Online Publication Date: May 1, 1994
• Publication Date: May 1, 1994
• Deposit Date: May 14, 2021
• Journal: American Journal of Physiology - Endocrinology and Metabolism
• Print ISSN: 0193-1849
• Electronic ISSN: 1522-1555
• Publisher: American Physiological Society
• Peer Reviewed: Peer Reviewed
• Volume: 266
• Issue: 5
• Pages: E776-E785
• DOI: https://doi.org/10.1152/ajpendo.1994.266.5.E776
• Public URL: https://nottingham-repository.worktribe.com/output/3185960
• Publisher URL: https://journals.physiology.org/doi/abs/10.1152/ajpendo.1994.266.5.E776