Effects of nandrolone decanoate on respiratory and peripheral muscles in male and female rats.
Thirty male and 18 female adult rats received weekly an intramuscular injection of either saline (control; C), 1.5 mg/kg (low-dose; LD) nandrolone decanoate or 7.5 mg/kg (high-dose; HD) nandrolone decanoate during 5 wk. Compared with respective C, growth rate was stunted in male HD rats from 2 wk of treatment on, whereas it was enhanced in female LD and HD rats after 1 wk. Mass of all muscles studied varied proportionally to body weight, except for the gastrocnemius (males: 0.49 +/- 0.04 vs. C: 0.52 +/- 0.03%, not significant; females: 0.17 +/- 0.01 vs. C: 0.15 +/- 0.01%, P < 0.05). In vitro contractile and fatigue properties of the diaphragm remained unchanged, except for a decrease in twitch kinetics (time to peak tension: C, 21 +/- 2; LD, 19 +/- 1; HD, 19 +/- 2 ms, P < 0.05; half-relaxation time: C, 26 +/- 5, LD, 25 +/- 5, HD, 23 +/- 3 ms, P < 0.01). Histochemistry of the diaphragm and the gastrocnemius revealed a significant increase in type IIx/b dimensions. In the gastrocnemius, type I fiber dimensions also increased. A pair-fed study, including another 24 female rats, showed that the changes in oral food intake only partly accounted for the observed anabolic effects.
Bisschop
A
A
Faculty of Physical Education and Physiotherapy, Katholieke Universiteit Leuven, Belgium.
Gayan-Ramirez
G
G
Rollier
H
H
Dekhuijzen
P N
PN
Dom
R
R
de Bock
V
V
Decramer
M
M
D045930:Anabolic Agents / Q000494:pharmacology*; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004435:Eating / Q000502:physiology; D004558:Electric Stimulation; D005260:Female; D006651:Histocytochemistry; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000502:physiology; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000378:metabolism; D009277:Nandrolone / Q000031:analogs & derivatives* / Q000494:pharmacology; D000077603:Nandrolone Decanoate; D009929:Organ Size / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D012132:Respiratory Muscles / Q000187:drug effects* / Q000378:metabolism; D012727:Sex Characteristics
D045930:Anabolic Agents; D009277:Nandrolone; D000077603:Nandrolone Decanoate