+ Site Statistics
+ Search Articles
+ PDF Full Text Service
How our service works
Request PDF Full Text
+ Follow Us
Follow on Facebook
Follow on Twitter
Follow on LinkedIn
+ Subscribe to Site Feeds
Most Shared
PDF Full Text
+ Translate
+ Recently Requested

Photoperiod-driven changes in reproductive function in male rhesus monkeys

Photoperiod-driven changes in reproductive function in male rhesus monkeys

Journal of Clinical Endocrinology and Metabolism 74(5): 1068-1074

Environmental lighting, which regulates seasonal breeding in many animal species, has not been examined as a regulator of reproduction or puberty in man or nonhuman primates. In this study we examined the effects of controlled alternating long and short daily photoperiods, independent of other environmental variables, on testicular size and function in rhesus monkeys. Sixteen animals, some pubertal, others prepubertal, were individually caged indoors in light-controlled rooms. They were subjected to a 32-week "year" with alternating 16-week cycles of long (16 h of light and 8 h of darkness) or short (8 h of light and 16 h of darkness) days. Animals were examined every 2 weeks over four 32-week "years". Body weight, testicular diameter, and testicular volume were measured, and blood was collected for testosterone and PRL determinations. We found that although short days did not trigger testicular development in prepubertal animals, testicular growth was markedly enhanced by short days in postpubertal animals, accompanied by increased plasma testosterone levels and reduced PRL levels. In long days, testes regressed, testosterone levels fell, and PRL levels rose. The periodicity of testicular size, as determined by spectral analysis, showed a strong signal at a cycle length of 31 +/- 13 weeks, but no signal at intervals close to the natural 52-week year, indicating that the observed periodicity is induced by the changes in lighting, rather than by circannual changes in other variables. These studies establish that changes in photo-period alone can modulate reproductive function in a higher primate and suggest that the onset of puberty is not directly driven by seasonal fluctuations in day length.

Please choose payment method:

(PDF emailed within 0-6 h: $19.90)

Accession: 040973447

Download citation: RISBibTeXText

PMID: 1569154

DOI: 10.1210/jcem.74.5.1569154

Related references

Effects of photoperiod on reproductive function in male rhesus monkeys. Clinical & Investigative Medicine 13(2): A3, 1990

Relation between the seasonal changes in aggression, plasma testosterone and the photoperiod in male rhesus monkeys. Psychoneuroendocrinology 6(2): 145-158, 1981

The association between rank and reproductive success of male rhesus monkeys. American Journal of Primatology 1(1): 83-90, 1981

Social dominance and reproductive behavior in male rhesus monkeys. American Journal of Physical Anthropology 35(2): 219-222, 1971

Pathological changes in the reproductive tract of male rhesus monkeys associated with age and simian AIDS. Journal Of Comparative Pathology. 107(1): 49-57, 1992

Reproductive behavior of captive male Rhesus monkeys (Macaca mulatta). Communs behav (Ser. A): 231-235, 1969

Intraepithelial lymphocytes in the male reproductive tract of rats and rhesus monkeys. Journal of Reproduction and Fertility 42(1): 1-7, 1975

Reproductive behavior of socially deprived male rhesus monkeys (Macaca mulatta). Journal of Comparative and Physiological Psychology 69(3): 403-407, 1969

Multi nucleated neurons associated with the reproductive tract of both male and female rhesus monkeys. Anatomical Record 169(2): 408, 1971

Effects of lead acetate exposure on reproductive functions in male rhesus monkeys. Zhongguo Yaolixue Yu Dulixue Zazhi 6(4): 285-288, 1992

Factors affecting social behavior and reproductive success of male rhesus monkeys. International Journal of Primatology 83: 281-292, 1987

Reproductive photorefractoriness in male rhesus monkeys appearance of endogenous circannual rhythms. Society for Neuroscience Abstracts 14(1): 440, 1988

Reproductive activity in relation to male dominance and the likelihood of ovulation in rhesus monkeys. Behavioral Ecology and Sociobiology 123: 215-228, 1983