World Class Bodybuilding   Forum

BulkSupplements Egg Whites International A1Supplements.com i-Supplements Strength.com VitaSprings Myprotein Beyondsupplements
Go Back   World Class Bodybuilding Forum > WorldClass RSS Feeds > Testosterone RSS feeds

Shoutbox
Loading...





Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 06-14-2018, 05:56 AM
basskiller's Avatar
basskiller basskiller Is Off Line
Administrator

 
Join Date: Jan 2004
Location: Bodybuilding heaven
Posts: 125,484
Thanks: 3,387
Thanked 18,377 Times in 10,666 Posts
Rep Power: 3956
basskiller has a reputation beyond reputebasskiller has a reputation beyond reputebasskiller has a reputation beyond reputebasskiller has a reputation beyond reputebasskiller has a reputation beyond reputebasskiller has a reputation beyond reputebasskiller has a reputation beyond reputebasskiller has a reputation beyond reputebasskiller has a reputation beyond reputebasskiller has a reputation beyond reputebasskiller has a reputation beyond repute
rss Standing variation and the capacity for change: are endocrine phenotypes more variabl

Standing variation and the capacity for change: are endocrine phenotypes more variable than other traits?

Integr Comp Biol. 2018 Jun 12;:

Authors: Miles MC, Vitousek MN, Husak JF, Johnson MA, Martin LB, Taff CC, Zimmer C, Lovern MB, Fuxjager MJ

Abstract
Circulating steroid hormone levels exhibit high variation both within and between individuals, leading some to hypothesize that these phenotypes are more variable than other morphological, physiological, and behavioral traits. This should have profound implications for the evolution of steroid signaling systems, but few studies have examined how endocrine variation compares to that of other traits or differs among populations. Here we provide such an analysis by first exploring how variation in three measures of corticosterone (CORT)- baseline, stress-induced, and post-dexamethasone injection- compares to key traits characterizing morphology (wing length, mass), physiology (reactive oxygen metabolite concentration [d-ROMs] and antioxidant capacity), and behavior (provisioning rate) in two populations of tree swallow (Tachycineta bicolor). After controlling for measurement precision and within-individual variation, we found that only post-dex CORT was more variable than all other traits. Both baseline and stress-induced CORT exhibit higher variation than antioxidant capacity and provisioning rate, but not oxidative metabolite levels or wing length. Variation in post-dex CORT and d-ROMs was also elevated in the higher-latitude population in that inhabits a less predictable environment. We next studied how these patterns might play out on a macroevolutionary scale, assessing patterns of variation in baseline testosterone (T) and multiple non-endocrine traits (body length, mass, social display rate, and locomotion rate) across 17 species of Anolis lizards. At the macroevolutionary level, we found that circulating T levels and the rate of social display output are higher than other behavioral and morphological traits. Altogether, our results support the idea that within-population variability in steroid levels is substantial, but not exceptionally higher than many other traits that define animal phenotypes. As such, circulating steroid levels in free-living animals should be considered traits that exhibit similar levels of variability from individual to individual in a population.


PMID: 29897574 [PubMed - as supplied by publisher]



This is an automated post
__________________

W C B B Sponsors
Southern Sarms

Beyondsupplements
Myprotein.com
Strength.com
i-Supplements
A1Supplements.com
PowderCity.com
BulkSupplements.com
Egg Whites International <---100% Bio-Available Egg White Protein


Remember... Any advice given on this board is just an opinion and not to be taken as medical advice. WCBB doesn't advocate or condone use of steroids. Check the laws in your country. WCBB just provides the platform in which to discuss such matters
Reply With Quote
Get your liquid egg whites here at EGG WHITES INTERNATIONAL

Reply

Bookmarks


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 05:43 AM.



Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
follow worldclassbodybuilding at facebook follow worldclassbodybuilding at pinterest follow worldclassbodybuilding at twitter