Estrogen Levels Influence Medullary Bone Quantity And Density In Female House Finches And Pine Siskins.

Estrogen Levels Influence Medullary Bone Quantity And Density In Female House Finches And Pine Siskins. Gen Comp Endocrinol. 2016 Dec 27;: Authors: Squire ME, Veglia MK, Drucker KA, Brazeal K, Hahn TP, Watts HE Abstract 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 4.5-5 months, reproductive condition was assessed and leg (femora) and wing (humeri) bones were collected for analysis using high-resolution (10 μm) 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 e...
Source: General and Comparative Endocrinology - Category: Endocrinology Authors: Tags: Gen Comp Endocrinol Source Type: research