Acute insulin-induced hypoglycaemia does not alter IGF-1 and LH release in cyclic mares.

This research investigates the impact of acute hypoglycaemia, caused by insulin injections, on the release of insulin-like growth factor-1 (IGF-1) and luteinizing hormone (LH) in cyclic mares. The study found no significant changes in the levels of these hormones despite the induced hypoglycaemia, indicating that short-term hypoglycaemia might not influence the hypothalamo-pituitary-ovarian axis.

Research Methodology

• The study was conducted to understand the relationship between acute hypoglycaemia and release of the hormones IGF-1 and LH in cyclic mares.
• Insulin was used to induce hypoglycaemia, replicating the lowered plasma glucose concentration found in lactating mares.
• Different doses of insulin (0.1 and 0.2 IU/kg body weight) were administered to horses, which resulted in hypoglycaemia over a period of nearly 10 hours.
• The levels of IGF-1 and LH were analysed before and after insulin administration to detect any potential changes due to hypoglycaemic conditions.

Research Findings

• All horses treated with insulin developed hypoglycaemia, however, the IGF-1 and LH hormone levels were unaltered before and after insulin administration.
• No significant difference between the two insulin treatments and the control treatment was noted.
• This suggests that inspite of hypoglycaemic conditions, the brain could procure sufficient glucose.

Interpretation and Conclusions

• The results suggest that short-term hypoglycaemia does not impact the hypothalamo-pituitary-ovarian axis, as IGF-1 and LH levels remained stable despite insulin-induced hypoglycaemia.
• The study concludes that an acute change in plasma glucose concentration may not be the only metabolic signal that correlates nutrition and somatic metabolism with reproductive function in horse mares.
• Further research is required to investigate other potential metabolic signals that link nutrition, somatic metabolism, and reproductive function.