Studies on equine prematurity 3: Insulin secretion in the foal during the perinatal period.

This research article focuses on examining how different factors influence beta cell function in foetal and newborn horses. Studies were conducted on both unborn foals and newborn foals to observe the production and regulation of insulin, with evidence being found of insulin in foetal blood as early as 150 days into gestation. Moreover, the researchers observed that the beta cell function was suppressed during anaesthesia and surgery. There is also indication of a positive correlation between the concentrations of insulin and glucose in the foal’s plasma at birth, irrespective of maturity or delivery method.

Insulin Secretion in Early Gestation

• In the study, insulin was detected in foetal horses as early as 150 days into the gestation period, which typically lasts 340 days.
• During the last third of the gestation period, the foetus’ beta cells were found to respond to both exogenous administration of glucose and arginine and to endogenous variations in glucose level.

Effects of Surgery and Anaesthesia

• It was observed that the function of beta cells, which are responsible for producing insulin, gets suppressed during anaesthesia a horse’s surgery.

Insulin and Glucose Levels at Birth

• The researchers found a significant positive relationship between the plasma concentrations of insulin and glucose at the time of the foal’s birth, regardless of whether the foal was premature or full term, or its method of delivery.
• The stream of this relationship was considerably less pronounced when comparing the postoperative foetal concentration. However, the sensitivity of the beta cells to glucose was eradicated only when the delivery was challenging or prolonged.

Observations Post-Birth

• After birth, there were no significant differences noticed in the plasma concentrations of insulin or glucose among full term foals delivered either spontaneously or induced.
• Interestingly, the spontaneously delivered foals showed a transient increase in the insulin concentration 15 minutes post-birth, an observation that was not detected in foals delivered by induction.
• Another important observation was that the plasma glucose concentrations were maintained during the 2 hours post-birth in the absence of sucking in both induced and spontaneously delivered full term foals.
• On the other hand, premature foals were found to have significantly lower plasma glucose concentrations at birth than full term foals.