brief
Louis
Daniel
D. Bikie,
Robert
H. Herman
Hagler,
ABSTRACT
Lance
To
determine
0. Loiini,
Sam
if vitamin
D
F. Hull,
deficiency
in and
would
retard
the
ability
of
muscle
to
hypertrophy rats in each
in response to mechanical stress, we severed the gastrocnemius tendon on one leg of of three groups, the treatment of which differed only in the amount of vitamin D in the diet. After 1 week the increased size of the soleus and plantaris in the leg in which the gastrocnemius was severed relative to that of the sham operated leg, was determined for each rat. Despite differences in body weight and serum calcium among the groups, we found no difference in the percent of muscle hypertrophy. We conclude that muscle hypertrophy can occur in response to local mechanical forces despite a deficient hormonal environment that otherwise retards growth. Am. J. Clii’i. Nuir. 32: 5 15-516, 1979.
Vitamin D deficiency results in muscular weakness as well as osteomalacia (1). Histological examination of affected muscles reveals individual muscle fiber atrophy (2). Protein synthesis in the muscle of rachitic rats is stimulated by vitamin D in vivo and by 25hydroxyvitamin D in vitro (3). Protein synthesis is necessary for work-induced muscle hypertrophy (4). Therefore, we evaluated whether or not vitamin D deficiency would inhibit work induced muscle hypertrophy. Methods Male weanling rats obtained from Holtzman Co. (Madison, Wis.) were raised on a vitamin D-deficient diet containing 0.43% calcium and 0.3% phosphorus (Tekiad Test Diet TD 75007). After 2 weeks, one group of animals (group A) was given 6.5 nmoles vitamin D3 orally in 100 s1 propylene glycol three times a week as supplement to the diet. Four weeks after beginning the vitamin D-deficient diet, the tendinous insertion of the left gastrocnemius of each rat was cut under pentobarbital anesthesia A sham operation was performed on the right gastrocnemius of each rat. One day before the operation, a second group of rats (group B) was started on 6.5 nmoles vitamin D3 orally three times a week. A third group of animals (group C) received no vitamin D at any time. After the operation the water bottle for each cage was raised to force the rats to stand on their hind limbs to drink. Goldberg et al. (4) have demonstrated
The American
Journal
of Clinical
Nutrition
32: MARCH
the
efficacy of this procedure to induce muscle hypertrophy in rats. One week after the operation the animals were killed, blood obtained for calcium analysis (5), and the soleus, plantaris, and gastrocnemius of each hind limb were removed and weighed. The extent of muscle hypertrophy was determined as the difference between the weights of each pair of intact muscles (left muscle
minus right muscle) divided by the weight of the right muscle. Statistical analysis was performed by Student’s I test.
Results The results are summarized in Table 1. The vitamin D-deficient rats had smaller body weights (mean body weight = 163 g) and lower serum calcium concentrations (mean serum calcium = 4.6 mg/dl). However, the tFrom Institute Francisco, 2The
the Department
of Medicine,
Research, Presidio California 94129. opinions or assertions of
of
Letterman San
contained
Army
Francisco, herein
San are
the
private views of the authors and are not to be construed as official or as reflecting the views of the Department of the Army or the Department of Defense. 31n conducting the research described in this report, the
investigators adhered to the Guide for Laboratory Facilities and Care, as promulgated by the Committee on the Guide for Laboratory Animal Resources, National Academy of Sciences, National Research Council.
Animal
1979, pp. 515-5 16. Printed
in U.S.A.
515
Downloaded from https://academic.oup.com/ajcn/article-abstract/32/3/515/4692028 by guest on 15 November 2018
Work-induced muscle hypertrophy vitamin 0-deficient rats1-3
communications
516 TABLE
BIKLE
ET
AL.
1
The influence of vitamin and muscle hypertrophy”
D on body
weight,
serum
calcium
concentration,
Group A’
203±9’
Serum Ca (mg/dl) Rsoleuswt(mg) % soleus wt (% soleus wt soleus) R plantaris wt (mg) % plantaris wI (%A plantaris plantaris/R plantaris) No. of rats
9.4 ± 0.2’ 82±6’ 29.3 ± 11
-
100 x L soleus
wt
-
-
R soleus/R
100 x L plantaris
-
163±11 4.6 ± 0.1
58±8 35.2
224 ± 10’ ±4
R
C’
167±15 9.0 ± 0.2’
± 22 9.0 ± 3
179
11.9
9
7
“Values are expressed as means ± SEM. b Rats received vitamin D for 3 weeks before received vitamin D for 1 week before they were killed. 1Rats received no vitamin D. group C. P < 0.0001 compared to group C.
rats given 6.5 nmoles (100 IU) vitamin D either the day before or 2 weeks before surgery showed no more capability to increase muscle size under an increased work load than those rats maintained in the vitamin D deficient state. This is indicated in Table 1 by the similar percent increase in size of the intact muscles (percentage A soleus weight, percentage A plantaris weight) of the operated leg (left) compared to those of the sham operated leg (right) in all three groups. In all groups the left soleus increased about 30 to 35% compared to the right whereas the left plantaris increased about 9 to 12% compared to the right.
56±6 34.7
±4
± 5
165 ± 13 12.1 ±4 9
they
were killed. C Rats P < 0.01 compared to
muscle hypertrophy despite its importance in growth is consistent with the observation that neither pituitary insufficiency nor insulin insufficiency retards work-induced muscle hypertrophy (6, 7). Apparently, the mechanisms by which vitamin D and other hormones regulate growth do not dominate muscle hypertrophy in response to local, mechanical forces. El The authors acknowledge the technical assistance of Ms. Lillian Johnson and the secretarial assistance of Ms. Helen Hunterman.
References 1. DENT,
E. E., AND R. SMrrIs. Nutritional osteomala3. Med. 38: 195, 1969. 2. MALLEI-rE, L. E., B. M. PATrEN AND W. K. ENGEL. Neuromuscular disease in secondary hyperparathyroidism. Ann. Internal Med. 82: 474, 1975. 3. BIRGE, S. 3., AND J. C. HADDAD. 25-Hydroxycholecalciferol stimulation of muscle metabolism. 3. Clin. Invest. 56: 1100, 1975. 4. GOLDBERG, A. L., J. D. ETLINGER, D. F. GOLDSPINK AND C. JABLEcKI. Mechanism of work-induced hypertrophy of skeletal muscle. Med. Sci. Sports 7: 185, cia.
Discussion The failure of vitamin D supplementation to enhance muscle hypertrophy cannot be attributed to its failure to stimulate growth as evidenced by the greater body and muscle weights of group A, the group that received vitamin D for the longest time. Nor did the vitamin D supplementation fail to raise serum calcium to normal levels in either group A or B. The percentage increase in muscle hypertrophy in the vitamin D-deficient animals is not only not different from the animals receiving vitamin D in this experiment but is comparable to the results obtained by Goldberg et al. (4) in normal growing rats. That vitamin D is not required for work-induced
Quart.
1975. 5. GINDLER, determination methylthymol 1972. 6.
E. M.,
AND 3. D. KING. Rapid colorimetric of calcium in biologic fluids with blue. Am. J. Clin. Pathol. 58: 376,
A. L. Work induced growth of skeletal muscle in normal and hypophysectomized rats. Am. J. Physiol. 213: 1193, 1967. 7. GOLDBERG, A. L. Role of insulin in work-induced growth of skeletal muscle. Endocrinology 83: 1071, GOLDBERG,
1968.
Downloaded from https://academic.oup.com/ajcn/article-abstract/32/3/515/4692028 by guest on 15 November 2018
Bodywt(g)
W
Louis
Daniel
D. Bikie,
Robert
H. Herman
Hagler,
ABSTRACT
Lance
To
determine
0. Loiini,
Sam
if vitamin
D
F. Hull,
deficiency
in and
would
retard
the
ability
of
muscle
to
hypertrophy rats in each
in response to mechanical stress, we severed the gastrocnemius tendon on one leg of of three groups, the treatment of which differed only in the amount of vitamin D in the diet. After 1 week the increased size of the soleus and plantaris in the leg in which the gastrocnemius was severed relative to that of the sham operated leg, was determined for each rat. Despite differences in body weight and serum calcium among the groups, we found no difference in the percent of muscle hypertrophy. We conclude that muscle hypertrophy can occur in response to local mechanical forces despite a deficient hormonal environment that otherwise retards growth. Am. J. Clii’i. Nuir. 32: 5 15-516, 1979.
Vitamin D deficiency results in muscular weakness as well as osteomalacia (1). Histological examination of affected muscles reveals individual muscle fiber atrophy (2). Protein synthesis in the muscle of rachitic rats is stimulated by vitamin D in vivo and by 25hydroxyvitamin D in vitro (3). Protein synthesis is necessary for work-induced muscle hypertrophy (4). Therefore, we evaluated whether or not vitamin D deficiency would inhibit work induced muscle hypertrophy. Methods Male weanling rats obtained from Holtzman Co. (Madison, Wis.) were raised on a vitamin D-deficient diet containing 0.43% calcium and 0.3% phosphorus (Tekiad Test Diet TD 75007). After 2 weeks, one group of animals (group A) was given 6.5 nmoles vitamin D3 orally in 100 s1 propylene glycol three times a week as supplement to the diet. Four weeks after beginning the vitamin D-deficient diet, the tendinous insertion of the left gastrocnemius of each rat was cut under pentobarbital anesthesia A sham operation was performed on the right gastrocnemius of each rat. One day before the operation, a second group of rats (group B) was started on 6.5 nmoles vitamin D3 orally three times a week. A third group of animals (group C) received no vitamin D at any time. After the operation the water bottle for each cage was raised to force the rats to stand on their hind limbs to drink. Goldberg et al. (4) have demonstrated
The American
Journal
of Clinical
Nutrition
32: MARCH
the
efficacy of this procedure to induce muscle hypertrophy in rats. One week after the operation the animals were killed, blood obtained for calcium analysis (5), and the soleus, plantaris, and gastrocnemius of each hind limb were removed and weighed. The extent of muscle hypertrophy was determined as the difference between the weights of each pair of intact muscles (left muscle
minus right muscle) divided by the weight of the right muscle. Statistical analysis was performed by Student’s I test.
Results The results are summarized in Table 1. The vitamin D-deficient rats had smaller body weights (mean body weight = 163 g) and lower serum calcium concentrations (mean serum calcium = 4.6 mg/dl). However, the tFrom Institute Francisco, 2The
the Department
of Medicine,
Research, Presidio California 94129. opinions or assertions of
of
Letterman San
contained
Army
Francisco, herein
San are
the
private views of the authors and are not to be construed as official or as reflecting the views of the Department of the Army or the Department of Defense. 31n conducting the research described in this report, the
investigators adhered to the Guide for Laboratory Facilities and Care, as promulgated by the Committee on the Guide for Laboratory Animal Resources, National Academy of Sciences, National Research Council.
Animal
1979, pp. 515-5 16. Printed
in U.S.A.
515
Downloaded from https://academic.oup.com/ajcn/article-abstract/32/3/515/4692028 by guest on 15 November 2018
Work-induced muscle hypertrophy vitamin 0-deficient rats1-3
communications
516 TABLE
BIKLE
ET
AL.
1
The influence of vitamin and muscle hypertrophy”
D on body
weight,
serum
calcium
concentration,
Group A’
203±9’
Serum Ca (mg/dl) Rsoleuswt(mg) % soleus wt (% soleus wt soleus) R plantaris wt (mg) % plantaris wI (%A plantaris plantaris/R plantaris) No. of rats
9.4 ± 0.2’ 82±6’ 29.3 ± 11
-
100 x L soleus
wt
-
-
R soleus/R
100 x L plantaris
-
163±11 4.6 ± 0.1
58±8 35.2
224 ± 10’ ±4
R
C’
167±15 9.0 ± 0.2’
± 22 9.0 ± 3
179
11.9
9
7
“Values are expressed as means ± SEM. b Rats received vitamin D for 3 weeks before received vitamin D for 1 week before they were killed. 1Rats received no vitamin D. group C. P < 0.0001 compared to group C.
rats given 6.5 nmoles (100 IU) vitamin D either the day before or 2 weeks before surgery showed no more capability to increase muscle size under an increased work load than those rats maintained in the vitamin D deficient state. This is indicated in Table 1 by the similar percent increase in size of the intact muscles (percentage A soleus weight, percentage A plantaris weight) of the operated leg (left) compared to those of the sham operated leg (right) in all three groups. In all groups the left soleus increased about 30 to 35% compared to the right whereas the left plantaris increased about 9 to 12% compared to the right.
56±6 34.7
±4
± 5
165 ± 13 12.1 ±4 9
they
were killed. C Rats P < 0.01 compared to
muscle hypertrophy despite its importance in growth is consistent with the observation that neither pituitary insufficiency nor insulin insufficiency retards work-induced muscle hypertrophy (6, 7). Apparently, the mechanisms by which vitamin D and other hormones regulate growth do not dominate muscle hypertrophy in response to local, mechanical forces. El The authors acknowledge the technical assistance of Ms. Lillian Johnson and the secretarial assistance of Ms. Helen Hunterman.
References 1. DENT,
E. E., AND R. SMrrIs. Nutritional osteomala3. Med. 38: 195, 1969. 2. MALLEI-rE, L. E., B. M. PATrEN AND W. K. ENGEL. Neuromuscular disease in secondary hyperparathyroidism. Ann. Internal Med. 82: 474, 1975. 3. BIRGE, S. 3., AND J. C. HADDAD. 25-Hydroxycholecalciferol stimulation of muscle metabolism. 3. Clin. Invest. 56: 1100, 1975. 4. GOLDBERG, A. L., J. D. ETLINGER, D. F. GOLDSPINK AND C. JABLEcKI. Mechanism of work-induced hypertrophy of skeletal muscle. Med. Sci. Sports 7: 185, cia.
Discussion The failure of vitamin D supplementation to enhance muscle hypertrophy cannot be attributed to its failure to stimulate growth as evidenced by the greater body and muscle weights of group A, the group that received vitamin D for the longest time. Nor did the vitamin D supplementation fail to raise serum calcium to normal levels in either group A or B. The percentage increase in muscle hypertrophy in the vitamin D-deficient animals is not only not different from the animals receiving vitamin D in this experiment but is comparable to the results obtained by Goldberg et al. (4) in normal growing rats. That vitamin D is not required for work-induced
Quart.
1975. 5. GINDLER, determination methylthymol 1972. 6.
E. M.,
AND 3. D. KING. Rapid colorimetric of calcium in biologic fluids with blue. Am. J. Clin. Pathol. 58: 376,
A. L. Work induced growth of skeletal muscle in normal and hypophysectomized rats. Am. J. Physiol. 213: 1193, 1967. 7. GOLDBERG, A. L. Role of insulin in work-induced growth of skeletal muscle. Endocrinology 83: 1071, GOLDBERG,
1968.
Downloaded from https://academic.oup.com/ajcn/article-abstract/32/3/515/4692028 by guest on 15 November 2018
Bodywt(g)
W
