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Fibroblast growth factor-21 improves insulin action in nonlactating ewes
Cassandra L Lamb1, Sarah L Giesy1, Molly M McGuckin1
1Department of Animal Science, Cornell University, Ithaca, New York.
Summary
Fibroblast growth factor-21 (FGF21) improved insulin action in nonlactating ewes, suggesting ruminants are responsive. Lactation may be an FGF21-resistant state, impacting nutrient use coordination.
Area of Science:
- Metabolic regulation and endocrinology.
- Ruminant physiology.
- Hormonal control of nutrient partitioning.
Background:
- Mammals coordinate nutrient use during metabolic stress by adjusting insulin sensitivity.
- Metabolic hormones like growth hormone, TNFα, and adiponectin modulate insulin action.
- Fibroblast growth factor-21 (FGF21) shows insulin-sensitizing effects in rodents and primates.
Purpose of the Study:
- To investigate if FGF21 improves insulin action in nonlactating ewes, addressing potential unresponsiveness in ruminants or lactation.
- To characterize the ovine FGF21 system and its receptor complex in target tissues.
Main Methods:
- Gene expression analysis to assess the ovine FGF21 system.
- Administration of FGF21 to nonlactating ewes for 13 days.
- Measurement of plasma glucose, insulin, adiponectin, and ceramide levels.
- Glucose tolerance tests to evaluate glucose disposal.
Main Results:
- Ovine FGF21 system mirrors other species, with liver as the primary expression site and adipose tissue as a target.
- FGF21 treatment reduced plasma glucose and insulin and enhanced glucose disposal.
- FGF21 increased plasma adiponectin but did not affect ceramide concentrations.
Conclusions:
- The insulin-sensitizing effects of FGF21 are conserved in ruminants.
- Lactation might represent a physiological state of FGF21 resistance in ruminants.
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