Effect of intravenous glucose and combined glucose-insulin challenges on energy-regulating hormones concentrations in donkeys.

This research explores how glucose and insulin challenges impact the concentrations of hormones that regulate energy in donkeys. The study looked at the insulin-glucagon ratio and how this changed during intravenous glucose tolerance and combined glucose-insulin tests. It also examined how these tests affected endocrine variables and measured the correlation with physical characteristics.

Objectives and Methods of the Study

• The primary goals of this study were to assess the insulin to glucagon (IGR) and glucagon to insulin (GIR) molar ratios under normal conditions and in response to intravenous glucose tolerance and combined glucose-insulin tests in healthy donkeys.
• The research also intended to explore the association between these ratios and endocrine elements (such as leptin, ghrelin and adiponectin) and certain physical variables.
• The study was conducted on 49 healthy adult donkeys. The intravenous glucose tolerance test (IVGTT) and combined glucose-insulin test (CGIT) were carried out on eight donkeys each, but the same tests could only be conducted on six donkeys due to the withdrawal of two from the study.

Results of the Study

• Under normal conditions, the findings showed that IGR and GIR median values in donkeys are 1.5 and 0.7, respectively.
• The IVGTT prompted an increase in the IGR (and decline in the GIR) from 15 to 180 minutes post the initiation of the test, but it didn’t affect leptin, adiponectin, or ghrelin concentrations.
• Conversely, CGIT caused a significant rise in the IGR (and a decrease in the GIR) from 15 to 120 minutes after the start of the test, and significantly increased plasma leptin concentrations at 240 minutes.
• The research found no link between the ratios, hormones, and physical measurements.

Significance and Implications of the Findings

• The results indicate the presence of variations between donkeys and horses, likely due to the proportionally higher glucagon compared to insulin concentrations in donkeys.
• This difference may be significant to disorders in donkeys related to energy regulation, such as metabolic syndrome and dyslipidaemias.
• The outcomes of this study lay the groundwork for further exploration and research into metabolic disorders in donkeys, a prevalent issue in this animal species.