Morphology of the cells of normal, testosterone‐deprived and testosterone‐stimulated levator ani muscles

Venable, John H.

doi:10.1002/aja.1001190206

Cited by 145 publications

(63 citation statements)

References 24 publications

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“…Because fibroblasts are far more numerous in muscle than are satellite cells (Venable, 1966), strategies to enhance regeneration must specifically target the latter cell type. Crushed muscle extract stimulates satellite cell growth in culture, but does not increase fibroblast proliferation above basal levels (Bischoff, 1986a;Chen and Quinn, 1992).…”

Section: Augmented Mincementioning

confidence: 99%

Enhancement of skeletal muscle regeneration

Bischoff

Heintz

1994

Developmental Dynamics

161

103

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We have studied the effect of adding extra satellite cells or soluble factors from crushed muscle on regeneration of minced fragments from rat tibialis muscle. The muscle mince was wrapped in an artificial epimysium to prevent adhesions and cell immigration from adjacent muscles. Regeneration was quantitatively assessed by electrophoretic determination of the muscle-specific form of creatine kinase. Control minces exhibited three periods of change in creatine kinase activity during a 7-week regeneration period. Activity fell rapidly during the first week, then rose gradually from 1 3 weeks and increased more rapidly from 3-7 weeks. To augment the original complement of myogenic cells, satellite cells were isolated from the contralateral muscle, purified by density gradient centrifugation, and expanded in culture for 3 days before adding to the muscle mince. The added cells resulted in a 3-fold enhancement of creatine kinase activity throughout the regeneration period. Soluble muscle extract incorporated into a collagen matrix also stimulated regeneration when added to muscle mince. The extract accelerated the rate of creatine kinase increase during the 1 3 week period beyond that observed in the control or cell augmented mince, suggesting that factors in the extract may facilitate revascularization or reinnervation. The specific activity of creatine kinase was increased in regenerates augmented with both cells and extract, indicating that the effects enhance primarily myogenic processes.

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Section: Augmented Mincementioning

confidence: 99%

Enhancement of skeletal muscle regeneration

Bischoff

Heintz

1994

Developmental Dynamics

161

103

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“…This can be prevented by the administration of testosterone (7,22). The changes due to castration or hormone administration take place at the level of the individual muscle fiber rather than as a result of changing the populations of muscle fibers within the muscle (20,21). Involution of this muscle in female rats can be prevented by the administration of testosterone (5,9).…”

Section: Introductionmentioning

confidence: 99%

The regeneration of a hormone-sensitive muscle (levator ani) in the rat

Gutmann

Carlson

1978

Experimental Neurology

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In l-month-old male rats the levator ani muscle was crushed and allowed to regenerate. The main questions were whether or not the course of regeneration is similar to that of limb muscles and whether or not the regenerating levator ani muscle is sensitive to the effects of testosterone. Regeneration was followed in three groups of rats: castrated, normal, and testosterone-treated.Histological analysis revealed no detectable differences between regeneration of the levator ani and other muscles. By 31 days both the gross weight and mean cross-sectional area of the muscle fibers in castrated rats were much less than in the other two groups. Testosterone-treated muscles were larger, but not significantly so, than normal regenerating muscles. Twitch and tetanic tensions were lowest in regenerating muscles from castrated rats and highest in those from hormone-treated rats. Both the contraction (time to peak) and half-relaxation times at 7 and 14 days were fastest in hormone-treated muscles and were very slow in castrated rats. By 30 days, the differences between normal and hormone-treated muscles had disappeared. It is concluded that the regenerating levator ani muscle is sensitive to the effects of testosterone.

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“…The muscles shrink markedly after adult castration and enlarge with androgen treatment in male rats and mice (Wainman and Shipounoff, 1941;Dorfman and Kincle, 1963;Vyskocil and Gutmann, 1977). These anabolic effects of androgens involve changes in perineal muscle fiber size, without a change in fiber number (Venable, 1966). Androgens in adulthood also maintain BC/LA neuromuscular junction size (Bleisch and Harrelson, 1989;Balice-Gordon et al, 1990;Lubischer and Bebinger, 1999), acetylcholine receptor number (Bleisch et al, 1982;Bleisch and Harrelson, 1989), and peripheral nerve activity (Fargo et al, 2003).…”

Section: Hormone Dependence Of the Bc/la Muscles In Adulthoodmentioning

confidence: 99%

The spinal nucleus of the bulbocavernosus: Firsts in androgen-dependent neural sex differences

Sengelaub

Forger

2008

Hormones and Behavior

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Cell number in the spinal nucleus of the bulbocavernosus (SNB) of rats was the first neural sex difference shown to differentiate under the control of androgens, acting via classical intracellular androgen receptors. SNB motoneurons reside in the lumbar spinal cord and innervate striated muscles involved in copulation, including the bulbocavernosus (BC) and levator ani (LA). SNB cells are much larger and more numerous in males than in females, and the BC/LA target muscles are reduced or absent in females. The relative simplicity of this neuromuscular system has allowed for considerable progress in pinpointing sites of hormone action, and identifying the cellular bases for androgenic effects. It is now clear that androgens act at virtually every level of the SNB system, in development and throughout adult life. In this review we focus on effects of androgens on developmental cell death of SNB motoneurons and BC/LA muscles; the establishment and maintenance of SNB motoneuron soma size and dendritic length; BC/LA muscle morphology and physiology; and behaviors controlled by the SNB system. We also describe new data on neurotherapeutic effects of androgens on SNB motoneurons after injury in adulthood.

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Morphology of the cells of normal, testosterone‐deprived and testosterone‐stimulated levator ani muscles

Cited by 145 publications

References 24 publications

Enhancement of skeletal muscle regeneration

Enhancement of skeletal muscle regeneration

The regeneration of a hormone-sensitive muscle (levator ani) in the rat

The spinal nucleus of the bulbocavernosus: Firsts in androgen-dependent neural sex differences

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