Effects of Nandrolone Treatment on Recovery in Horses After Strenuous Physical Exercise

Abstract

To test the effect of nandrolone on their recovery, six adult half-bred riding horses performed a competition exercise test (CET) and a standardized exercise test (SET) on consecutive days before and after a 2-week treatment with the anabolic steroid nandrolone laurate. Blood samples were collected during and between these tests for the determination of red cell volume and concentrations of blood lactate, plasma glucose, non-esterified fatty acids, glycerol, triglycrides, erythropoietin, cortisol, insulin, and glucagon. Muscle biopsy specimens were taken immediately after the CET and before the SET for analysis of glycogen content, citrate synthase, and 3-hydroxyacyl CoA dehvdrogenase activity. Nandrolone administration increased the rate of muscle glycogen repletion after exercise, an increase that may be explained by increased glucose output by the liver, higher plasma insulin concentration, and increased insulin-independent glucose transport, but not by better availability of lipid fuels during recovery.

An evidence‐based analysis of anabolic steroids as performance enhancers in horses

“…On the other hand, another study failed to detect an increase in red cell volume or erythropoietin levels (Hyyppä 2001). This was attributed to a shorter duration of treatment with nandrolone laurate in this study than the previous studies.…”

“…Several studies have examined the effect of anabolic steroids on various muscle characteristics. Muscle water content does not appear to be changed by treatment (Nimmo et al 1982;Snow et al 1982a) nor does muscle glycogen content (Nimmo et al 1982;Snow et al 1982a;Hyyppä et al 1997;Hyyppä 2001), nor total mean protein concentration (Nimmo et al 1982;Snow et al 1982a;Hyyppä et al 1997). Total mean protein concentration did, however, increase during the follow-up period after treatment (Hyyppä et al 1997).…”

“…Although muscle glycogen content does not appear to be affected by anabolic steroids, one study found that glycogen repletion after exercise is enhanced (Hyyppä 2001). Glycogen repletion rate after exercise trials corresponding with steroid administration was significantly higher when compared with that of glycogen repletion after exercise trials in the same horses without anabolic steroid treatment.…”

An evidence‐based analysis of anabolic steroids as therapeutic agents in horses

“…Published data in horses with clinical disease related to muscle recovery are limited. Nandrolone increased the rate of muscle glycogen repletion in treated animals after strenuous exercise (Hyyppa 2001). Whether strenuous exercise correlates well with muscle damage during clinical disease is unclear.…”

A review of designer anabolic steroids in equine sports

“…In contrast to the well‐documented advantages that anabolic steroids offer to human athletes, the effects of anabolic steroids in equine competitors are not well‐established . A study has shown that short‐term nandrolone (17β‐hydroxyestr‐4‐en‐3‐one) administration increased the glycogen content of post‐exercise muscle tissue; however, this is in contrast with two studies that found no observable changes resulting from nandrolone administration . It has been shown that steroid administration delayed closure of epiphyseal growth plates in Standardbreds, and suggested that this could lead to a potential increase to the long‐term risks of injury during training .…”