scholarly journals Age and Long-Term Hormone Treatment Effects on the Ultrastructural Morphology of the Median Eminence of Female Rhesus Macaques

2015 ◽  
Vol 103 (6) ◽  
pp. 650-664 ◽  
Author(s):  
Michelle M. Naugle ◽  
Sateria A. Lozano ◽  
Fay A. Guarraci ◽  
Larry F. Lindsey ◽  
Ji E. Kim ◽  
...  
Keyword(s):  
Median Eminence ◽  
Treatment Effects ◽  
Rhesus Macaques ◽  
Hormone Treatment ◽  
Ultrastructural Morphology ◽  
Female Rhesus ◽  
Female Rhesus Macaques

scholarly journals Effect of Housing Conditions on Cortisol and Body Fat Levels in Female Rhesus Macaques

Biology ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 744
Author(s):  
Dian G. M. Zijlmans ◽  
Lisette Meijer ◽  
Marit K. Vernes ◽  
Jacqueline A. M. Wubben ◽  
Linda Hofman ◽  
...  
Keyword(s):  
Body Fat ◽  
Individual Variation ◽  
Rhesus Macaques ◽  
Dominance Rank ◽  
Individual Characteristics ◽  
Study Results ◽  
Female Rhesus ◽  
Cortisol Levels ◽  
Female Rhesus Macaques

Macaques are among the most commonly used non-human primates in biomedical research. They are highly social animals, yet biomedical studies often require group-living animals to be pair-housed in a controlled environment. A change in environment causes only short-term stress in adapting individuals, while non-adapting animals may experience long-term stress that can adversely affect study results. Individuals likely differ in their ability to adapt depending on individual characteristics. Changes in cortisol and body fat levels may reflect these different individual responses. Here, we investigate the long-term effect of a change from group- to pair-housing on cortisol and body fat levels in 32 female rhesus macaques, exploring whether age, dominance rank, original cortisol, and body fat levels are related to long-term stress in pair-housing. Hair samples were analyzed for cortisol levels, while anthropometric measurements and computed tomography were performed to quantify body fat. Monkeys served as their own control with a 7.5-month period between the measurements. Cortisol levels increased, while average body fat levels did not differ when individuals were moved from group- to pair-housing. Cortisol and body fat levels were not significantly correlated. Changes in cortisol were independent of age and dominance rank, whereas individual variation in body fat alterations was related to the group-housed body fat level and dominance rank. Although this study did not identify individual characteristics related to long-term stress in pair-housing, the individual variation confirms that some individuals are more resilient to change than others and provides possibilities for future refinement studies.

scholarly journals Neuroestradiol in the Stalk Median Eminence of Female Rhesus Macaques Decreases in Association With Puberty Onset

Endocrinology ◽  
2016 ◽  
Vol 157 (1) ◽  
pp. 70-76 ◽  
Author(s):  
Brian P. Kenealy ◽  
Kim L. Keen ◽  
Amita Kapoor ◽  
Ei Terasawa
Keyword(s):  
Median Eminence ◽  
Rhesus Macaques ◽  
Neural Substrates ◽  
Gonadal Steroid ◽  
Subsequent Reduction ◽  
Female Rhesus ◽  
Gnrh Release ◽  
Central Inhibition ◽  
Puberty Onset ◽  
Female Rhesus Macaques

Abstract In primates, despite the fact that GnRH neurons are mature at birth, a gonadal steroid independent central inhibition restrains the initiation of puberty. The neural substrates responsible for this central inhibition, however, are unclear. In this study, we tested the hypothesis that neuroestradiol release in the hypothalamus decreases prior to the pubertal increase in GnRH release. We found that in female monkeys at the prepubertal stage, when GnRH release was low, estradiol (E2) levels in the stalk-median eminence of the hypothalamus were higher than those in older, early pubertal females in which nocturnal GnRH release begins to increase. Furthermore, estrone (E1) levels were higher in the stalk-median eminence of prepubertal and early pubertal monkeys compared with midpubertal monkeys, which have the highest GnRH release. The elevated E2 and E1 levels at the prepubertal stage are likely hypothalamic in origin because circulating E2 and E1 levels in prepubertal and early pubertal monkeys were much lower than those in midpubertal monkeys. Heightened synthesis and release of neuroestradiol during the prepubertal period and subsequent reduction at puberty onset indicate possible roles for neuroestradiol in central inhibition of GnRH release. The mechanism governing the reduction in neuroestradiol synthesis at puberty onset remains to be determined.

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