Castration reduces motoneuron soma size but not dendritic length in the spinal nucleus of the bulbocavernosus of wild‐type and BCL‐2 overexpressing mice

Park, Joong Jean; Zup, Susan L.; Verhovshek, Tom; Sengelaub, Dale R.; Forger, Nancy G.

doi:10.1002/neu.10103

Cited by 22 publications

(21 citation statements)

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“…The relative decrease in BC/LA muscle and seminal vesicle mass after adult castration are comparable to previous findings in both mice and rats (Wainman & Shipounoff, 1941;Park et al, 2002;Forger & Breedlove 1987;Jordan et al, 2002).…”

Section: Discussionsupporting

confidence: 89%

“…The following day, spinal cords were transversely sectioned on a freezing, sliding microtome at 40 μm. Sections were reacted with tetramethylbenzidine for histological visualization of HRP according to Park et al (2002). After the reaction, alternate sections were mounted onto three separate gelatin-coated slides.…”

Section: Methods Experimentsmentioning

confidence: 99%

“…Forger and Breedlove (1986) showed that in white footed mice (Peromyscus leucopus) SNB dendritic length decreased 7 weeks following castration. However, the B6D2F1 laboratory mouse failed to show a decrease in dendritic length after either 6 or 12 weeks of castration (Park et al, 2002).…”

Section: Introductionmentioning

confidence: 91%

“…They found that SNB somas shrank in DBA/2J and B6D2F1 strains but not in C57BL6 mice. Another study examining the effects of a shorter term castration (6 weeks) in B6D2F1 mice also show a decrease in SNB soma size (Park et al, 2002). The role of adult circulating androgens in maintaining SNB dendrites has been examined in two species of mice.…”

Section: Introductionmentioning

confidence: 99%

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Androgen-sensitivity of somata and dendrites of spinal nucleus of the bulbocavernosus (SNB) motoneurons in male C57BL6J mice

Zuloaga

Morris

Monks

et al. 2007

Hormones and Behavior

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In rats, androgens in adulthood regulate the morphology of motoneurons in the spinal nucleus of the bulbocavernosus (SNB), including the size of their somata and the length of their dendrites. There are conflicting reports about whether androgens exert similar influences on SNB motoneurons in mice. We castrated or sham-operated C57BL6J mice at 90 days of age and, thirty days later, injected cholera toxin conjugated horseradish peroxidase into the bulbocavernosus muscle (to label SNB motoneurons) on one side, and into intrinsic foot muscles contralaterally (to label motoneurons of the retrodorsolateral nucleus (RDLN)). Castrated mice had significantly smaller SNB somas compared to sham operated mice while there were no differences in soma size of RDLN motoneurons. Dendritic length in C57BL6J mice, estimated in 3-dimensions, also decreased significantly after adult castration. In rats, androgens act directly through androgen receptors (AR) in SNB motoneurons to control soma size and nearly all their SNB motoneurons contain AR. Since SNB somata in C57BL6J mice shrank after adult castration, we used immunocytochemistry to characterize AR expression in SNB cells as well as motoneurons in the RDLN and dorsolateral nucleus (DLN). A pattern of labeling matched that seen previously in rats: the highest percentage of AR-immunoreactive motoneurons are in the SNB (98%), the lowest in the RDLN (25%), and an intermediate number in the DLN (78%). This pattern of AR labeling is consistent with the possibility that androgens also act directly on SNB motoneurons in mice to regulate soma size in mice.

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Section: Discussionsupporting

confidence: 89%

Section: Methods Experimentsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 91%

Section: Introductionmentioning

confidence: 99%

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Androgen-sensitivity of somata and dendrites of spinal nucleus of the bulbocavernosus (SNB) motoneurons in male C57BL6J mice

Zuloaga

Morris

Monks

et al. 2007

Hormones and Behavior

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“…In addition, the effect of androgen on motor neuron has been demonstrated in some animal studies, in which motor neuron size was reduced in castrated mice. It is therefore plausible that the efficiency or quality of muscle contractility can be adversely affected by the co-existing motor neuron atrophy related to sexhormone decline (30,31).…”

Section: Discussionmentioning

confidence: 99%

Testosterone but not estradiol level is positively related to muscle strength and physical performance independent of muscle mass: a cross-sectional study in 1489 older men

Auyeung¹,

Lee²,

Kwok³

et al. 2011

European Journal of Endocrinology

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Objective: To examine the relationship between different measures of testosterone and estradiol (E 2 ), muscle mass, muscle strength, and physical performance; and to test whether the association of sex hormone level with muscle strength and physical performance was independent of muscle mass. Design and methods: A cross-sectional survey on 1489 community-dwelling men older than 64 years of age. Serum levels of testosterone and E 2 were measured by mass spectrometry, and sex hormonebinding globulin (SHBG) levels were measured by immunoradioassay. Muscle mass was examined by dual-energy X-ray absorptiometry and physical performance was assessed by hand-grip strength, gait speed, step length and chair-stand test. Results: Appendicular skeletal mass (ASM) was positively associated with total testosterone (TT; P!0.001), free testosterone (FT; P!0.001), and total E 2 (P!0.001) but not with free E 2 (PZ0.102). After adjustment for age, serum SHBG and relative ASM, both TT and FT were significantly associated with grip strength, narrow-walk speed and the composite neuromuscular score. Higher total E 2 , but not free E 2 was associated with lower grip strength (P!0.05) after adjustment for age, FT, SHBG and relative ASM. Conclusions: Testosterone level was related to both muscle mass, strength and physical performance. Total E 2 level, though related to muscle mass positively, affected muscle strength adversely in older men. European Journal of Endocrinology 164 811-817 IntroductionSeveral studies have examined the inter-relationship between various measures of testosterone level, muscle mass and muscle strength (1-6). In men aged 65 or older, Baumgartner et al.(1) reported that free testosterone index, but not total testosterone (TT) level, was modestly associated with muscle mass, whereas Iannuzzi-Sucich et al. (2) demonstrated that muscle mass was correlated to bioavailable testosterone (BioT), leg strength and physical performance. However, in another cohort of healthy older men, Van den Beld et al. (3) reported that testosterone level, as represented by TT and BioT, was related to muscle strength but not to muscle mass. On the other hand, Roy et al. (5) observed that TT and BioT were positively correlated with both the muscle mass and strength, yet after adjustment for muscle mass, they were no longer independently associated with muscle strength. Szulc et al. (4) had compared the muscle mass and physical performance of hypogonadal and eugonadal men and found that hypogonadal men exhibited impaired static and dynamic balance despite relatively preserved muscle mass. Similarly, Orwoll et al. (6) have observed that testosterone level was related to physical performance and fall risk but not to muscle mass. Although the effect of testosterone supplementation on muscle mass and strength was less controversial in interventional studies (7-14), whether endogenous testosterone was related to muscle mass alone, muscle strength alone, or both; and which measures of endogenous testosterone best related to muscle ...

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Increase in motoneurons in the spinal nucleus of the bulbocavernosus of prepubertally castrated male Mongolian gerbils following delayed treatment with testosterone

Siegford

Ulibarri

2004

J of Comparative Neurology

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Sexual dimorphism in the spinal nucleus of the bulbocavernosus (SNB) of the Mongolian gerbil is achieved by two periods of postnatal increase, one in the first month after birth and one at puberty. The pubertal increase in motoneuron number is of particular interest because it occurs in a nearly adult animal. The purpose of this research was threefold. The first was to determine the response of the SNB in prepubertally castrated male gerbils receiving delayed hormone replacement as adults. Testosterone propionate (TP) treatment resulted in numbers of SNB motoneurons comparable to those seen in intact males, whereas androgen metabolites were less effective. The second purpose was to determine the latency of motoneurons to appear in response to TP. New SNB motoneurons appeared within 2 days of delayed TP replacement in prepubertally castrated males, and 16 days of treatment did not further increase SNB motoneuron numbers. The response of the motoneurons to TP appeared more rapid than the response of the bulbocavernosus (BC) muscle, scent gland, and seminal vesicles. The third purpose was to determine whether the new cells were connected to a target muscle. After 16 days of TP treatment, more motoneurons were labeled in the SNB following injection of a retrograde tract tracer into the BC muscle compared with the number seen in control animals. Thus, new motoneurons appeared in the SNB of prepubertally castrated male Mongolian gerbils within 2 days of the start of delayed TP treatment and were connected to a target within 16 days of TP treatment.

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Castration reduces motoneuron soma size but not dendritic length in the spinal nucleus of the bulbocavernosus of wild‐type and BCL‐2 overexpressing mice

Cited by 22 publications

References 48 publications

Androgen-sensitivity of somata and dendrites of spinal nucleus of the bulbocavernosus (SNB) motoneurons in male C57BL6J mice

Androgen-sensitivity of somata and dendrites of spinal nucleus of the bulbocavernosus (SNB) motoneurons in male C57BL6J mice

Testosterone but not estradiol level is positively related to muscle strength and physical performance independent of muscle mass: a cross-sectional study in 1489 older men

Increase in motoneurons in the spinal nucleus of the bulbocavernosus of prepubertally castrated male Mongolian gerbils following delayed treatment with testosterone

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