Insulin

Insulin is released post-prandially with little to no basal secretion in the absence of dietary
stimulation. Insulin is highly anabolic and its primary physiologic functions include storage of
nutrients (as fat or glycogen), preserving tissue stores (inhibiting gluconeogenesis) and also
many diverse metabolic effects such as controlling blood vessel contraction and cellular
growth and differentiation.
Insulin dysregulation (ID) is a common metabolic status associated with genetic factors,
obesity, diets high in non-structural carbohydrate (NSC=sugar+starch+fructan), physical
inactivity and further endocrine changes including PPID, pregnancy, stress and pain, and also
exogenous glucocorticoids. ID tends to result in augmented secretion of insulin which may

then trigger hyperinsulinaemia-associated laminitis, probably via stimulation of lamellar IGF-
1 receptors by high concentrations of insulin.

Choosing the type of insulin test depends on the exact question that is being asked:
If you want to know whether or not the individual has ID, then the most practical and sensitive
test is measuring insulin at 60-90 minutes following an oral sugar test of 0.45 mL/kg Karo Light
Corn Syrup. This also indicates the potential for laminitis if fed inappropriately or if exogenous
glucocorticoids are administered.
Alternatively, if you want to know what the actual risk of laminitis is in an individual then it is
most useful to measure postprandial insulin collected after consumption of the different
dietary elements (preserved forage, fresh grass, other feeds), bearing in mind that insulin
peaks around 2 hours after consumption. However, it must be recognised that insulin
response will change along with grass quality or changes in batch of hay, requiring periodic
retesting. Evidence suggests that measuring the nutritional quality (eg starch and sugar
content) of forages and other feeds is not predictive of the insulin responses to those feeds
and is no substitute for measuring post-prandial insulin.

See also:
EMS
PPID
ACTH
Glucose
Adiponectin