To compare physiological and developmental differences between two cogeneric species that differ by seasonal vs. aseasonal breeding, values for morphological measurements, testicular volume, serum testosterone, estradiol, and dehydroepiandrosterone-sulfate levels were obtained from 53 rhesus during the early breeding season, as well as 41 pig-tailed macaque males maintained at the Tulane Primate Center. The two species exhibited similar body size, testosterone, and estradiol levels, but differed substantially in testicular volume (3.00 +/- 1.7 vs. 1.72 +/- 1.3 cc), abdominal skinfold measures (15.7 +/- 9.2 vs. 9.0 +/- 7.7 mm), and DHEA-S levels (18.0 +/- 11.7 vs. 7.6 +/- 5.4 microg/dl). Significant interaction effects for species by age group were found for weight, tricep circumference, length, and estradiol level. In addition, length was more closely related to testicular volume among rhesus compared to pig-tailed macaques, suggesting different developmental patterns between the species. Predictors of hormonal levels differed between the two species. In the rhesus, estradiol levels were related to testicular volume and testosterone levels while there were no anthropometric predictors of testosterone or DHEA-S. For the pig-tailed macaques, testicular volume was related to tricep circumference, testosterone to triceps skinfold and testicular volume, and estradiol to weight. It is argued that rhesus have larger testes for body size and more abdominal fat deposits during the early breeding season relative to pig-tailed macaques reflecting the increased demands of sperm competition in a seasonally breeding species. Hormonal differences associated with the difference in breeding system appear to be primarily related to adrenal rather than testicular activity.
Though baboons have been considered an appropriate non-human primate model for studying human reproductive and endocrine development. the overall similarity of reproductive maturation between the two species is unclear. This paper examines the role of testicular and adrenal hormones for pubertal changes in a cross-sectional sample of 21 captive male savanna baboons. Morphometric and hormonal indices demonstrate changes in size and gonadal function, but not adrenal function, during pubertal maturation among baboons. Results also indicate that gonadal, but not adrenal, androgens are related to morphometric variables. We conclude that savanna baboons do not make an appropriate evolutionary model of human pubertal maturation.
To compare physiological and developmental differences between two cogeneric species that differ by seasonal vs. aseasonal breeding, values for morphological measurements, testicular volume, serum testosterone, estradiol, and dehydroepiandrosterone-sulfate levels were obtained from 53 rhesus during the early breeding season, as well as 41 pig-tailed macaque males maintained at the Tulane Primate Center. The two species exhibited similar body size, testosterone, and estradiol levels, but differed substantially in testicular volume (3.00 +/- 1.7 vs. 1.72 +/- 1.3 cc), abdominal skinfold measures (15.7 +/- 9.2 vs. 9.0 +/- 7.7 mm), and DHEA-S levels (18.0 +/- 11.7 vs. 7.6 +/- 5.4 microg/dl). Significant interaction effects for species by age group were found for weight, tricep circumference, length, and estradiol level. In addition, length was more closely related to testicular volume among rhesus compared to pig-tailed macaques, suggesting different developmental patterns between the species. Predictors of hormonal levels differed between the two species. In the rhesus, estradiol levels were related to testicular volume and testosterone levels while there were no anthropometric predictors of testosterone or DHEA-S. For the pig-tailed macaques, testicular volume was related to tricep circumference, testosterone to triceps skinfold and testicular volume, and estradiol to weight. It is argued that rhesus have larger testes for body size and more abdominal fat deposits during the early breeding season relative to pig-tailed macaques reflecting the increased demands of sperm competition in a seasonally breeding species. Hormonal differences associated with the difference in breeding system appear to be primarily related to adrenal rather than testicular activity.
A survey of specific parasites in fecal samples randomly collected from socially housed rhesus monkeys was done over a 1-year period. Differences in frequency of samples with parasites, and number of different species per sample, were assessed by social group composition, social group size, female reproductive status, and season of the year. Common parasites were Entamoeba coli, lodamoeba biitschlii, Balantidium coli, Strongyloides fulleborni, and Trichuris trichiura. Samples from juvenile/subadult groups had more species of potentially pathogenic parasites per sample but fewer species of nonpathogenic parasites per sample than samples from adult groups. When group size reached 12 to 16 animals, the number of samples with helminths doubled. Samples collected from groups with gestating/ lactating females had more species of nonpathogenic parasites than samples collected from groups with cycling or noncycling females. Fewer samples collected in the spring had helminths than samples collected during the fall, winter, and summer. The number of potentially pathogenic species present per sample was highest during the summer. Following anthelminthic treatment, the number of helminthic species present per sample and the number of samples with helminths remained low, then began increasing after 2 to 3 months. The number of potentially pathogenic species per sample decreased while animals were fed an inadvertently vitamin C deficient chow. o 1992 Wiley-Liss, Inc.
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