Assessment of endogenous growth hormone pulsatility in gelded yearling horses using deconvolution analysis.

Hypothesis/objectives: Defining normal Growth Hormone (GH) secretory dynamics in the horse is necessary to understand altered GH dynamics related to issues like welfare and disease.

Animals And Methods: Twelve healthy yearlings and two mature Standardbreds were used to quantify GH secretion. Endogenous GH half-life was determined after administration of 1.

(Over)training effects on quantitative electromyography and muscle enzyme activities in standardbred horses.

Too intensive training may lead to overreaching or overtraining. To study whether quantitative needle electromyography (QEMG) is more sensitive to detect training (mal)adaptation than muscle enzyme activities, 12 standardbred geldings trained for 32 wk in age-, breed-, and sex-matched fixed pairs. After a habituation and normal training (NT) phase (phases 1 and 2, 4 and 18 wk, respectively), with increasing intensity and duration and frequency of training sessions, an intensified training (IT) group (phase 3, 6 wk) and a control group (which continued training as in the last week of phase 2) were formed.

Effect of exercise on activation of the p38 mitogen-activated protein kinase pathway, c-Jun NH2 terminal kinase, and heat shock protein 27 in equine skeletal muscle.

Objective: To investigate the effects of exercise on activation of mitogen-activated protein kinase (MAPK) signaling proteins in horses.

Animals: 6 young trained Standardbred geldings.

Procedure: Horses performed a 20-minute bout of exercise on a treadmill at 80% of maximal heart rate.

Effects of short- and long-term recombinant equine growth hormone and short-term hydrocortisone administration on tissue sensitivity to insulin in horses.

Objective: To determine the effects of short-term IV administration of hydrocortisone or equine growth hormone (eGH) or long-term IM administration of eGH to horses on tissue sensitivity to exogenous insulin.

Animals: 5 Standardbreds and 4 Dutch Warmblood horses.

Procedure: The euglycemic-hyperinsulinemic clamp technique was used to examine sensitivity of peripheral tissues to exogenous insulin 24 hours after administration of a single dose of hydrocortisone (0.

Investigation of the expression and localization of glucose transporter 4 and fatty acid translocase/CD36 in equine skeletal muscle.

Objective: To investigate the expression and localization of glucose transporter 4 (GLUT4) and fatty acid translocase (FAT/CD36) in equine skeletal muscle.

Sample Population: Muscle biopsy specimens obtained from 5 healthy Dutch Warmblood horses.

Procedures: Percutaneous biopsy specimens were obtained from the vastus lateralis, pectoralis descendens, and triceps brachii muscles.

Immunohistochemical identification and fiber type specific localization of protein kinase C isoforms in equine skeletal muscle.

Objective: To investigate whether protein kinase C (PKC) isoforms are expressed in equine skeletal muscle and determine their distribution in various types of fibers by use of immunofluorescence microscopy.

Animals: 5 healthy adult Dutch Warmblood horses.

Procedure: In each horse, 2 biopsy specimens were obtained from the vastus lateralis muscle.