PMID- 3950563
OWN - NLM
STAT- MEDLINE
DCOM- 19860416
LR  - 20061115
IS  - 0022-104X (Print)
IS  - 0022-104X (Linking)
VI  - 237
IP  - 2
DP  - 1986 Feb
TI  - Metamorphosis of the American eel, Anguilla rostrata LeSeur: I. Changes in 
      metabolism of skeletal muscle.
PG  - 173-84
AB  - Unequivocal demarcation between immature, nonmigratory yellow eels and migratory 
      silver eels of greater sexual maturity is possible by measuring eye diameter and 
      retinal capillary length, which undergo a 1.5- and 2.3-fold increase during 
      metamorphosis, respectively. Anatomical arrangement of trunk musculature is 
      similar in the two groups except for an increased depth of slow muscle in silver 
      eel. Histochemical analysis reveals a progressive increase in numbers of 
      "displaced" fast fibres within slow muscle of the lateral line triangle in 
      maturing eels, although these are unlikely to affect recruitment pattern of 
      muscle fibre types. Previous studies have suggested greater involvement of fast 
      muscle in locomotion of migratory eels. In contrast, estimates of enzyme activity 
      in fast muscle suggest an inadequate aerobic capacity to fuel sustained activity. 
      Myoglobin content is extremely low, around 0.4 nM g wet wt-1. Prolonged anaerobic 
      metabolism is also discounted as a migratory strategy. Increased energy provision 
      for migration is apparently derived from increased capacity for both aerobic 
      carbohydrate metabolism and mitochondrial fatty acid oxidation within slow muscle 
      of silver eels. Activity of hexokinase (HK) shows a 1.6-fold increase (to 0.51 
      microM g wet wt-1) and carnitine palmitoyltransferase (CPT) a 3.1-fold increase 
      (to 0.22 microM g wet wt-1 min-1), suggesting a maximal flux through these 
      pathways of 18 and 14 ATP equivalents, respectively. However, the fatty acyl 
      transferase system of skeletal muscle mitochondria displays up to threefold 
      greater activity with palmitoleoyl CoA (C16:1) as substrate than with the usual 
      palmitoyl CoA (C16:0). Slow muscle of silver eel is therefore capable of deriving 
      aerobic energy from free fatty acids and carbohydrate in the ratio 2.3:1. 
      Differences in aerobic enzyme activities are not paralleled by myoglobin content 
      of slow muscle, being 15 and 16 nM g wet wt-1 for yellow and silver eel, 
      respectively. Structural reorganization of muscle fibres during metamorphosis, 
      however, results in a twofold elevation of cytoplasmic myoglobin concentration in 
      silver eel. It would appear that dramatic differences in metabolic capacity 
      between life history stages of eel is required to overcome locomotory 
      inefficiency of yellow eels and to "preadapt" silver eels for migratory activity. 
      This increased locomotory capacity may be amplified by a subsequent training 
      response.
FAU - Egginton, S
AU  - Egginton S
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, Non-P.H.S.
PL  - United States
TA  - J Exp Zool
JT  - The Journal of experimental zoology
JID - 0375365
RN  - 0 (Enzymes)
RN  - 0 (Myoglobin)
SB  - IM
MH  - Aging
MH  - Anguilla/*growth & development
MH  - Animals
MH  - Body Weight
MH  - Enzymes/metabolism
MH  - Female
MH  - Male
MH  - *Muscle Development
MH  - Muscles/cytology/metabolism
MH  - Myoglobin/analysis
MH  - Organ Size
MH  - Sexual Maturation
EDAT- 1986/02/01 00:00
MHDA- 1986/02/01 00:01
CRDT- 1986/02/01 00:00
PHST- 1986/02/01 00:00 [pubmed]
PHST- 1986/02/01 00:01 [medline]
PHST- 1986/02/01 00:00 [entrez]
AID - 10.1002/jez.1402370204 [doi]
PST - ppublish
SO  - J Exp Zool. 1986 Feb;237(2):173-84. doi: 10.1002/jez.1402370204.