Effects of nandrolone phenylpropionate in the horse: (3) Skeletal muscle composition in the exercising animal

Abstract

Summary The effect of 11 weekly injections of nandrolone phenylpropionate (400 mg) on some skeletal muscle parameters was investigated in 6 Thoroughbred geldings undergoing training. Three muscles were sampled, the middle gluteal, the biceps femoris and the semitendinosus. Training alone produced increases in the percentage of fast twitch high oxidative fibres (KM), glycogen content and the activities of citrate synthase, 3‐hydroxyacl CoA dehydrogenase and cytochrome oxidase. In contrast the training programme did not alter water content, total protein content, the activities of lactate dehydrogenase, phosphofructokinase or β glucuronidase, fibre area ratios or the number of capillaries per unit fibre area. Nandrolone phenylpropionate given in conjunction with the training programme only resulted in changes in 2 of these parameters. There was no increase in the percentage of FTH fibres in the biceps femoris with anaerobic training and the fibre area ratio increased significantly in this muscle. Résumé Les effets de 11 injections hebdomadaires de phénylpropionate de nandrolone (400 mg) sur quelques paramètres musculaires ont été recherchés sur 6 hongres de Pur Sang soumis à l'entraînement. Trois muscles ont servi aux prélèvements; le fessier moyen, le biceps femoris (partie postérieure du long vaste) et le semi tendineux. L'entraînement seul produisit l'accroissement du pourcentage des fibres a contraction rapide (FTH), l'accroissement du glycogène de ces muscles et l'accroissement des activités de la citrate synthase, de la 3‐hydroxyacyl CoA deshydrogènase, de la cytochrome oxydase. Par contre l'entraînement ne modifia pas la proportion d'eau, la proportion des proteines totales, ni l'activité des lactate deshydrogènase, phosphofructokinase et β‐glucuronidase, ni le rapport du nombre de fibres par unité de surface ni le nombre de capillaires par unité de surface. Le phénylpropionate de nandrolone administré en conjonction avec le programme d'entraînement modifia seulement 2 de ces paramètres. Il n'y eu pas d'accroissement du nombre des fibres à contraction rapide dans le biceps femoris à la suite d'entraînement anaérobie; le rapport, des fibres par unité de surface s'éleva de manière significative dans ce muscle. Zusammenfassung Die Auswirkungen von elf, im Abstand von einer Woche verabreichten Injektionen von Nandrolon Phenylpropionat (400 mg) auf einige Skelettmuskel‐Parameter wurden bei 6 Vollblutwallachen im Training untersucht. Drei Muskel wurden berücksichtigt: der mittlere glutaeus, der biceps femoris und der semitendinosus. Das Training allein rief eine Vermehrung der schnell kontrahierenden Fasern mit hohem Oxydations‐potential (FTH = fast twitch high oxidative) hervor und auch der Glycogengehalt, sowie die Aktivität der Citratsynthetase, der 3‐Hydroxyacyl‐CoA‐Dehydrogenase und der Cytochrom‐Oxydase waren erhöht. Im Gegensatz dazu veränderte das Training weder den Wasser‐, noch den Gesamt‐Eiweissgehalt und unverändert blieben auch die Aktivitäten der Laktat‐ Dehydrogenase, der Phosphofructokinase und der...

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

“…Activities of CS and HAD were significantly elevated after AS treatment. Nimmo et al. (1982) found an increase with training but no difference in CS and HAD between AS horses compared to similarly trained control horses.…”

Effects of a submaximal treadmill training programme on histochemical properties, enzyme activities and glycogen utilisation of skeletal muscle in the horse

“…THE ability of equine skeletal muscle to accommodate changes in demand associated with training has been demonstrated during the last decade. Most studies have focussed attention on the changes in muscle composition of either Standardbred Trotters (Lindholm and Piehl 1974; EssCn, Lindholm and Thornton 1980; Taylor and Brassard 1981; EssCn-Gustavsson er a1 1983 ;Henckel 1983a) or Thoroughbreds and/or Heavy Hunters (Guy and Snow 1977a, b;Snow and Guy 1979; Nimmo, Snow and Munro 1982 Thomas and Fregin 1981; Thornton er al 1983), whereas others have examined the cardiovascular (Bayly, Gabel and Barr 1983) and cardiorespiratory (Thomas, Fregin, Gerber and Ailes 1983) responses of horses subjected to submaximal treadmill training programmes. However, there appear to be no reports of the changes occurring in equine skeletal muscle as a result of treadmill training.…”

Nitrogen utilization and metabolic responses of ponies to intense anaerobic exercise

“…An increase in FOG fibers due to training was also reported by Nimmo et al (1982) , Uehara et al (1985) and Hodgson et al (1985).…”

“…Furthermore, increases in both muscle size and mitochondrial size and mass are often seen as a result of muscular activity (Karpovich, 1965;Goldspink, 1970;Gollnick et al, 1973;Nimmo and Snow, 1982). Forrest et al (1975) (Rasch and Pierson, 1962; Goldspink, 1970; Laurent and Millward, 1980), however Edgerton (1978) , Gonyea (1980) and Ho (1980) have reported fiber splitting, as well as hypertrophy, in response to high intensity resistance training.…”