Effects of hydrocortisone on substrates of energy metabolism in alpacas.
OBJECTIVE
To evaluate effects of hydrocortisone administration, with and without concurrent administration of insulin, on intermediary metabolism in alpacas.


METHODS
8 adult castrated male alpacas.


METHODS
On each of 2 consecutive days, food was withheld from alpacas for 8 hours. Alpacas then were administered 1 mg of hydrocortisone sodium succinate/kg, IV (time 0). On 1 of the days, randomly assigned alpacas were also administered regular insulin (0.2 U/kg, IV) 120 minutes after hydrocortisone administration. Blood samples were collected at 0, 120, 135, 150, 165, 180, 210, 240, 300, and 360 minutes. Plasma concentrations of glucose and lactate and serum concentrations of triglycerides, cholesterol, nonesterified fatty acids, and beta-hydroxybutyrate were determined. Data were compared between days. Additionally, serum insulin concentrations before and after hydrocortisone administration were determined for selected samples.


RESULTS
Hydrocortisone administration induced hyperglycemia, hyperinsulinemia, a reduction in concentrations of triglycerides and cholesterol, and a reduction in triglyceride-to-cholesterol ratio. Subsequent insulin administration temporarily negated the hyperglycemic effects of hydrocortisone, induced temporary hyperlactemia, and augmented the reduction in blood triglycerides.


CONCLUSIONS
A single dose of a short-acting corticosteroid does not increase blood lipid fractions in healthy alpacas, probably because of a competent endogenous insulin response. Corticosteroids may induce differing responses in camelids with depleted glycogen stores or an ineffective insulin response. Administration of insulin can effectively negate the hyperglycemic effects of hydrocortisone and augment lipoprotein clearance. Hence, insulin administration may be therapeutic for alpacas with hyperglycemia, hyperlipemia, or hyperketonemia.
Cebra
Christopher K
CK
Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis 97331-4802, USA.
Tornquist
Susan J
SJ
McKane
Shaun A
SA
D020155:3-Hydroxybutyric Acid / Q000097:blood; D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D002161:Camelids, New World / Q000378:metabolism*; D002784:Cholesterol / Q000097:blood; D004734:Energy Metabolism / Q000187:drug effects*; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005508:Food Deprivation; D006854:Hydrocortisone / Q000009:adverse effects / Q000494:pharmacology*; D007328:Insulin / Q000494:pharmacology; D019344:Lactic Acid / Q000097:blood; D008297:Male; D013997:Time Factors; D014280:Triglycerides / Q000097:blood
D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D014280:Triglycerides; D019344:Lactic Acid; D002784:Cholesterol; D020155:3-Hydroxybutyric Acid; D006854:Hydrocortisone