Journal article
Estrogen levels influence medullary bone quantity and density in female house finches and pine siskins
General and comparative endocrinology, Vol.246, pp.249-257
05/15/2017
Handle:
https://hdl.handle.net/2376/110777
PMCID: PMC5392170
PMID: 28039066
Abstract
•Estradiol was experimentally elevated in female house finches and pine siskins.•Estradiol stimulated medullary bone (MB) formation in both species.•Estradiol did not affect cortical bone (MB) in either species.•Effect of estradiol on MB was observed in both femur and humerus of pine siskins.•Timing of MB formation in control females coincided with yolk deposition.
Medullary bone, a non-structural osseous tissue, serves as a temporary storage site for calcium that is needed for eggshell production in a number of avian species. Previous research focusing primarily on domesticated species belonging to the Anseriformes, Galliformes, and Columbiformes has indicated that rising estrogen levels are a key signal stimulating medullary bone formation; Passeriformes (which constitute over half of extant bird species and are generally small) have received little attention. In the current study, we examined the influence of estrogen on medullary bone and cortical bone in two species of Passeriformes: the Pine Siskin (Spinus pinus) and the House Finch (Haemorhous mexicanus). Females of these species received either an estradiol implant or were untreated as a control. After 4.5–5months, reproductive condition was assessed and leg (femora) and wing (humeri) bones were collected for analysis using high-resolution (10μm) micro-computed tomography scanning. We found that in both species estradiol-treated females had significantly greater medullary bone quantity in comparison to untreated females, but we found no differences in cortical bone quantity or microarchitecture. We were also able to examine medullary bone density in the pine siskins and found that estradiol treatment significantly increased medullary bone density. Furthermore, beyond the effect of the estradiol treatment, we observed a relationship between medullary bone quantity and ovarian condition that suggests that the timing of medullary bone formation may be related to the onset of yolk deposition in these species. Further research is needed to better understand the precise timing and endocrine regulation of medullary bone formation in Passerines and to determine the extent to which female Passerines rely on medullary bone calcium during the formation of calcified eggshells.
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Details
- Title
- Estrogen levels influence medullary bone quantity and density in female house finches and pine siskins
- Creators
- Maria E Squire - Department of Biology, The University of Scranton, PA, United StatesMegan K Veglia - Department of Biology, The University of Scranton, PA, United StatesKevin A Drucker - Department of Biology, The University of Scranton, PA, United StatesKathleen R Brazeal - Department of Neurobiology, Physiology & Behavior, University of California, Davis, United StatesThomas P Hahn - Department of Neurobiology, Physiology & Behavior, University of California, Davis, United StatesHeather E Watts - Department of Neurobiology, Physiology & Behavior, University of California, Davis, United States
- Publication Details
- General and comparative endocrinology, Vol.246, pp.249-257
- Publisher
- Elsevier Inc
- Identifiers
- 99900574623501842
- Language
- English
- Resource Type
- Journal article