Influence of month of birth on the serum hormone concentrations and weights of the accessory sex organs and testes during maturation of the male laboratory rat
The serum hormone concentrations of testosterone, LH and prolactin were studied in cohorts of male rats born one group/month over 20 consecutive months to determine the influence of month of birth on serum hormone concentrations observed at given ages during maturation. There was a significant effec...
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Published in | Biology of reproduction Vol. 22; no. 2; pp. 119 - 133 |
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Main Authors | , |
Format | Journal Article |
Language | English |
Published |
United States
Society for the Study of Reproduction
01.03.1980
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Subjects | |
Online Access | Get full text |
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Summary: | The serum hormone concentrations of testosterone, LH and prolactin were studied in cohorts
of male rats born one group/month over 20 consecutive months to determine the influence of
month of birth on serum hormone concentrations observed at given ages during maturation. There
was a significant effect of both age and month of birth on the concentrations of the three hormones studied. Serum levels
of testosterone increased with age and reached maximal levels at
50-70 days of age in rats born in the spring and at 80-90 days of age in rats born in the fall.
Serum LH levels were generally elevated at 30-40 days of age and then declined to adult levels
by 60 days of age. However, secondary rises in serum LH levels were noted in 70-90-day-old rats
born in the spring. Serum prolactin levels increased with age from 30 to 80 days of age. There was
a further elevation of serum levels of prolactin in mature animals (120 or 150 day old) in all
months of birth except in those born during the spring and early summer.
The changes in weights of testes and accessory sex organs (ventral prostate, seminal vesicle,
coagulating gland) of maturing male rats were studied in cohorts of animals born during different
consecutive months for the last 14 months of the above study. The weights of the accessory sex
organs were significantly affected by the month in which the animals were born, with rats born
in the spring (March-May) exhibiting accelerated growth during maturation as compared to rats
born at other times of the year. Changes in the weights of the testes during maturation were not
influenced by month of birth.
These results indicate that serum hormone concentrations and weights of accessory sex organs
of sexually maturing male rats are influenced by the month of birth, even though the animals
are maintained under controlled environmental conditions. |
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Bibliography: | L L10 ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0006-3363 1529-7268 |
DOI: | 10.1095/biolreprod22.2.119 |