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Home , Boldenone undecylenate, Nandrolone laurate

388 EQUINE VETERINARY EDUCATION / AE / August 2007

Evidence-based Clinical Question An evidence-based analysis of anabolic as performance enhancers in horses S. C. PITTS* AND M. DAVIS Department of Physiological Sciences, Center for Veterinary Health Sciences, Oklahoma State University, Stillwater, Oklahoma 74078, USA.

Introduction reasons for lack of response, in fact, evidence of performance augmentation has never been demonstrated in an Anabolic steroids are synthetic analogues with experimental setting (Hyyppä et al. 1995). Indeed, persuasive androgenic and anabolic properties. These compounds evidence, albeit circumstantial, that mitigates against a accomplish their anabolic effects by promoting a positive consistent beneficial effect of administration is the fact nitrogen balance and supporting constructive metabolism, that geldings compete successfully (Anon 1982). while decreasing tissue destruction (Scoggins 1980; Snow 1993). Traditionally, anabolic steroids have been used to Anabolic steroids and nitrogen balance improve appetite, increase muscle tone and general vigour, improve stamina and brighten hair coat (Scoggins 1980). The primary purported effect of anabolic steroids is the Therapeutic uses of anabolic steroids have included the promotion of a positive nitrogen balance. Many studies have treatment of debilitated horses, anaemic horses and horses analysed nitrogen retention and excretion, as well as total urea recovering from surgery; to speed healing and return to work and creatinine excretion during and after the administration of from minor injuries (Snow 1993); and to assist in recovery anabolic steroids. The results of such studies are inconsistent. from malnutrition, parasitism, physical exhaustion, While one study observed significantly increased nitrogen glucocorticoid-produced osteoporosis, fractures and mental retention 12–25 days after injection when fatigue (Beroza 1981). Furthermore, anabolic steroids are used compared with preinjection, nitrogen retention was not as management supplements to increase muscle size, strength further increased by a second injection of anabolic steroid and stamina, improve skeletal development, and promote (O’Connor et al. 1973). A significant increase in nitrogen aggressiveness in equine athletes (Beroza 1981). retention in 2 of 4 horses was observed during treatment with phenylpropionate, and a significant decrease in Anabolic steroids and performance nitrogen excretion was found in 3 of 4 horses during administration (Snow et al. 1982a). Nitrogen excretion was Most of the evidence to support the use of anabolic steroids lower in anabolic steroid treated animals than in controls, but in equine athletes is anecdotal. It is believed that anabolic only in one of 2 trials by one author (Snow et al. 1982b). steroids give athletes an extra edge in intense competition, Control horses had a negative energy balance, while the and that they do so by promoting appetite, appearance and treatment horses did not, thereby leading to speculation that stamina (Dawson and Gersten 1978). One uncontrolled report perhaps anabolic steroids promote a positive nitrogen balance claimed enhanced appetite and general tonus, accelerated by preventing tissue breakdown associated with training. return to training after treatment of various ailments of However, in that regard, there was no difference between the tendons, muscles, fascia and joints, and subsequent improved 2 groups with respect to urea and creatinine excretion. performance on the racetrack as a result of methandione administration (Vigre 1963). Anabolic steroids and weight Despite this anecdotal evidence, several studies have failed to show any improvement as a result of their administration Most studies have found that anabolic steroids either generate (Snow et al. 1982ab; Hyyppä et al. 1995). While inappropriate weight gain or limit weight loss. Animals twice treated with training regime (Snow et al. 1982b) and inadequate anabolic 1.1 mg/kg bwt undecyclenate had significantly steroid dose (Snow et al. 1982a) have been cited as possible higher weight gains than control animals (O’Connor et al. 1973). However, this significant difference in weight gain was *Author to whom correspondence should be addressed. not observed in animals treated with boldenone EQUINE VETERINARY EDUCATION / AE / August 2007 389

undecyclenate at 0.275 mg/kg bwt. Foals treated with capillaries per unit fibre area does not appear to be affected anabolic steroids during their first year of life were significantly by steroid administration (Nimmo et al. 1982), and neither heavier than foals that were not treated (Keenan et al. 1987). does the mean receptor concentration in muscle Control animals lost weight during a study of the effects cells. A correlation, however, was noted between mean of nandrolone phenylpropionate on animals in training (Snow concentration and percentage of Type IIA et al. 1982b). However, this weight loss was only seen in the fibres in the treated group, but not the control group. This anabolic steroid-treated animals after the anaerobic training thereby suggests the possibility that androgen receptor phase of the experiment, but not throughout the entire number in muscle cells could have an influence on conversion experiment. There were no significant differences between of those cells to Type IIA fibres, (Hyyppä et al. 1997) and could treatment and control groups with respect to change in body elucidate a link between anabolic steroid administration and measurements. In contrast, in another study, there was no increased percentage of Type IIA fibre. change in bodyweight as a result of treatment with Although muscle glycogen content does not appear to be nandrolone phenylpropionate (Snow et al. 1982a). affected by anabolic steroids, one study found that glycogen repletion after exercise is enhanced (Hyyppä 2001). Glycogen Anabolic steroids and red blood cells repletion rate after exercise trials corresponding with steroid administration was significantly higher when compared with Red blood cell volume has been shown to have a positive that of glycogen repletion after exercise trials in the same correlation with performance ability. The effect of anabolic horses without anabolic steroid treatment. In addition, insulin, steroids on red cell volume has been investigated in various glucagon and cortisol were significantly higher after exercise studies. One study noted a 20% increase in red cell volume as when anabolic steroids were administered than in control a consequence of anabolic steroid administration (Hyyppä et al. trials. The hormone balance that exists after exercise in 1994). In another study, red cell volume increased significantly anabolic steroid treated horses could conceivably increase in treated horses and remained increased 13 weeks after glucose output from the liver, blood insulin concentration and treatment, while no significant increase was observed in insulin-independent glucose uptake by the muscles, but this control horses. Interestingly, a positive correlation between red has yet to be demonstrated. cell volume and V200 (a measure of aerobic capacity) as well as The change in muscle composition induced by anabolic between red cell volume and total performance was found in steroids with respect to fibre type has been assessed in several the control group of horses, but not in the anabolic steroid studies (Nimmo et al. 1982; Snow et al. 1982a; Hyyppä et al. treated group (Hyyppä et al. 1995) and no hypothesis to 1995, 1997). No change in muscle fibre type composition in explain this absence of correlation in individuals treated with the semitendinosus muscle was seen in response to anabolic steroids was offered. steroid administration, however an increase in the proportion On the other hand, another study failed to detect an of Type I fibres and concomitant decrease in proportion of increase in red cell volume or erythropoietin levels (Hyyppä Type II fibres was observed in the biceps femoris (Snow et al. 2001). This was attributed to a shorter duration of treatment 1982a). A significant difference between control and anabolic with in this study than the previous steroid treated groups with respect to percentage of Type IIB studies. Other studies (O’Connor et al. 1973; Snow et al. fibres was found in the biceps femoris following anaerobic 1982b) have also found no significant increase in red cell training (Nimmo et al. 1982). A statistically significant change volume of treated horses over control horses. However, the in fibre composition of the middle gluteal muscle was found in time of sample collection (post exercise vs. post feeding) may treated horses, but not control horses (Hyyppä et al. 1995). have influenced these results (Hyyppä et al. 1995). Similar, but insignificant changes were noted in control horses, which persisted beyond cessation of training. This led to Anabolic steroids and muscle speculation that the difference in effects of training on the muscles of anabolic steroid treated animals when compared It has been suggested that anabolic steroid administration with controls is related to the time course over which these could directly affect muscle cells, and that the observed effects take place, and that adaptations to training may occur variation in the effects of anabolic steroids could be attributed more quickly in treated animals than controls. However, to the innate disparities between different muscles and the conflicting results in the middle gluteal were obtained in muscles of different individuals (Ryan 1976). Several studies another study (Hyyppä et al. 1997) although a moderate, have examined the effect of anabolic steroids on various rather than high, intensity training regimen was used during muscle characteristics. Muscle water content does not appear the experiment. to be changed by treatment (Nimmo et al. 1982; Snow et al. Muscle activity has been employed as a means of 1982a) nor does muscle glycogen content (Nimmo et al. 1982; investigating the consequences of anabolic steroid Snow et al. 1982a; Hyyppä et al. 1997; Hyyppä 2001), nor administration, but has failed to show effects of anabolic total mean protein concentration (Nimmo et al. 1982; Snow et steroid administration. No changes in the activity of aspartate al. 1982a; Hyyppä et al. 1997). Total mean protein aminotransferase, alanine aminotransferase, citrate synthase, concentration did, however, increase during the follow-up lactate dehydrogenase, aldolase or 3-hydroxyacyl-CoA period after treatment (Hyyppä et al. 1997). The number of dehydrogenase were seen as a result of anabolic steroid 390 EQUINE VETERINARY EDUCATION / AE / August 2007

treatment in one study (Snow et al. 1982a), nor were changes Anabolic steroids and behaviour in lactate dehydrogenase, phosphofructokinase or β-glucuronidase activity seen in another. While an increase in Finally, it has also been hypothesised that theoretical improved citrate synthase and 3-hydroxyacyl-CoA dehydrogenase activity performance that occurs as a result of anabolic steroid therapy was identified in treated animals following anaerobic training, could be due to changes in behaviour. Several studies have and an increase in cytochrome oxidase activity was observed in observed increased stallion-like behaviour in treated both treated and control groups (Nimmo et al. 1982), these individuals, although the degree to which each individual was hormones have been known to fluctuate in response to type affected varied (Nimmo et al. 1982; Snow et al. 1982a,b; and intensity of exercise, and this variation could simply be a Hyyppä et al. 1995). Only one study has reported no reflection of that fact. The activities of citrate synthase and undesirable side effects in horses treated with anabolic steroids 3-hydroxyacyl CoA dehydrogenase were significantly elevated (O’Connor et al. 1973). These virilising effects lasted as long as after treatment with anabolic steroids in one study (Hyyppä 6 weeks after cessation of anabolic steroid administration, 2001); however, in another study by the same author, no such which is longer than metabolites of the steroids were found in increase was seen (Hyyppä et al. 1997). In the latter study, urine (Snow et al. 1982b). It has been suggested that the lactate dehydrogenase activity appeared to decrease in both androgenic effects of anabolic steroids enhance the horse’s treated and control groups. Such variation in study results motivation and ability to train, thereby indirectly increasing makes it impossible to draw any concrete conclusions as to the muscle performance (Freed et al. 1975); however, enhanced effect of anabolic steroids on muscle enzyme activity. motivation was not observed in treated horses that were Other physiological parameters trained with a pace horse (Hyyppä et al. 1995).

Other measures of physiological status, including blood Conclusion creatinine levels, total protein, sodium, potassium, chloride, , , phosphorus, alkaline phosphatase, The physiological and psychological consequences of anabolic aspartate aminotransferase, creatine kinase, white blood cell steroid use in horses is highly inconsistent, and appears to count, urine specific gravity and urine pH, have shown no depend on a number of factors, including the steroid used, as significant effect from anabolic steroid treatment (Snow et al. well as the individual animal. There is a high degree of 1982b). Although it never exceeded the normal reference variability and irregularity in the response of the numerous range, a significant increase in γ-glutamyl transferase activity physiological parameters to anabolic steroid treatment and was noted in one study (Snow et al. 1982a), but not in subsequent exercise. It is possible that the parameters that another (Snow et al. 1982b). A significant increase in plasma correlate with improved athletic performance are not affected urea, phosphate and cholesterol following treatment was sufficiently to produce detectable performance enhancement. shown in one study (Snow et al. 1982a), but, again, not in It is also possible that a satisfactory experimental model for the another (Snow et al. 1982b). It should be noted that elevated investigation of anabolic steroid effects has yet to be plasma urea levels could indicate that nitrogen retention designed. Nevertheless, despite much anecdotal support of resulting from anabolic steroids could be due to higher blood the benefit of anabolic steroid use in equine athletes, there is nitrogen levels in treated animals rather than an anabolic little scientific evidence with which to corroborate it, and there effect (Snow et al. 1982a); that is, the nitrogen retained by is little evidence that anabolic steroid treatment offers an steroid treated animals is circulating and not incorporated into advantage in equine athletic performance. muscle tissue, as has been traditionally assumed. No change in serum cortisol or growth hormone levels References resulted from anabolic steroid treatment in one study, (Hyyppä et al. 1997) however a subsequent study observed a Anon (1982) Clinical consequences of anabolic steroids in competing significant decrease in cortisol levels for 30 min following horses: Imaginary or real? Equine vet. J. 14, 181-182. exercise in anabolic steroid treated horses (Hyyppä 2001). Beroza, G.A. (1981) Anabolic steroids in the horse. J. Am. vet. med. Plasma triglyceride levels were increased during exercise in Ass. 179, 278-280. control animals, but not in those given anabolic steroids, Dawson, H.A. and Gersten, K.E. (1978) Use of an anabolic steroid in thereby suggesting that prompt glycogen repletion in muscles racetrack practice. Mod. vet. Pract. 59, 129-130. after exercise in treated animals is not due to increased fat Freed, D.L.J., Banks, A.J., Longson, D. and Burley, D.H. (1975) availability in the blood (Hyyppä 2001). Anabolic steroids in athletics: crossover double blind trial on weightlifters. Br. med. J. 2, 471-473. Finally, anabolic steroids were not found to have an effect on peak heart rate (Hyyppä 2001), V (Hyyppä et al. 1995), Hyyppä, S. (2001) Effects of nandrolone treatment on recovery in 200 horses after strenuous physical exercise. J. Am. vet. med. Ass. or VLa4 (a measure of anaerobic capacity) (Hyyppä et al. 1994, 48, 343-352. 2001). Peak blood lactate concentration was similar in treated Hyyppä, S., Rasanen, L.A., Persson, S.G.B. and Pösö A.R. (1994) and control horses (Hyyppä 2001). Curiously, a correlation Anabolic steroids and exercise performance in finnhorse trotters. between blood lactate and performance time was detected in In: Proceedings of the 10th International Conference of Racing control, but not treated horses (Hyyppä et al. 1997). Analysts and Veterinarians, Stockholm, Sweden. pp 180-181. EQUINE VETERINARY EDUCATION / AE / August 2007 391

Hyyppä, S., Rasanen, L.A., Persson, S.G.B. and Pösö, A.R. Ryan, A.J. (1976) Anabolic-androgenic steroids. In: Handbook of (1995) Exercise performance indices in normal and anabolic steroid Experimental Pharmacology no. 43. Springer-Verlag, Berlin. treated trotters. Equine vet. J., Suppl. 18, 443-447. pp 515-534. Hyyppä, S., Karvonen, U., Rasanen, L.A., Persson, S.G.B. and Pösö, Scoggins, R.D. (1980) The anabolic agents. Equine Pract. 2, 26-30. A.R. (1997) Androngen receptors and skeletal muscle composition Snow, D.H. (1993) Anabolic steroids. Vet. Clin. N. Am.: Equine Pract. in trotters treated with nandrolone laureate. J. Am. vet. med. Ass. 9, 563-576. 44, 481-491. Snow, D.H., Munro, C.D. and Nimmo, M.A. (1982a) Effects of Keenan, D.M., Bruce, I.J. and Allardyce, C.J. (1987) The effect of nandrolone phenylpropionate in the horse: (1) resting animal. breed, date of birth, and anabolic steroids on the bodyweight of Equine vet. J. 14, 219-223. foals. Aust. vet. J. 64, 32. Snow, D.H., Munro, C.D. and Nimmo, M.A. (1982b) Effects of Nimmo, M.A., Snow, D.H. and Munro, C.D. (1982) Effects of nandrolone phenylpropionate in the horse: (2) general effects in nandrolone phenylpropionate in the horse: (3) skeletal muscle animals undergoing training. Equine vet. J. 14, 224-228. composition in the exercising animal. Equine vet. J. 14, 229-233. Vigre, E. (1963) Experience with methandione. Vet. Rec. 75, 769-771. O’Connor, J.J., Stillions, M.C., Reynolds, W.A., Linkenheimer, W.H. and Maplesden, D.C. (1973) Evaluation of as If you have a submission for a future Clinical Question to be included an anabolic agent in horses. Can. vet. J. 14, 154-158. in EVE, please contact David Ramey at [email protected]