PMID- 26078369
OWN - NLM
STAT- MEDLINE
DCOM- 20161108
LR  - 20200930
IS  - 1557-7023 (Electronic)
IS  - 1540-7063 (Linking)
VI  - 55
IP  - 2
DP  - 2015 Aug
TI  - Measurements of Neuronal Soma Size and Estimated Peptide Concentrations in 
      Addition to Cell Abundance Offer a Higher Resolution of Seasonal and Reproductive 
      Influences of GnRH-I and GnIH in European Starlings.
PG  - 332-42
LID - 10.1093/icb/icv063 [doi]
AB  - Hypothalamic neuropeptides involved in vertebrate reproduction, gonadotropin 
      releasing hormone (GnRH-I) and gonadotropin-inhibitory hormone (GnIH), can vary 
      in the abundance of immunoreactive cells as a function of the reproductive status 
      and nest box occupation of European starlings (Sturnus vulgaris). While using the 
      abundance of cells as an indicator of the activity of neurohormones is 
      informative, incorporating information on cell size (readily observed using 
      immunohistochemistry) can offer a more detailed understanding of 
      environmentally-mediated changes in hormonal dynamics. In this study, we tested 
      the hypothesis that the size of cells' somas and the estimated concentration of 
      peptides in cells immunoreactive (ir) for GnRH-I and GnIH would vary throughout 
      the breeding season and as a function of nest-box status (resident or not). In 
      the absence of a direct assay of protein, we estimated an index of the 
      concentration of hypothalamic peptides via the relative optical density (i.e., 
      the difference between the mean optical density and the optical density of 
      background staining). In support of our hypothesis, we found that GnRH-I- and 
      GnIH-ir soma size and peptide concentration changed both in males and females 
      throughout the breeding season. Somas were largest and estimated peptide 
      concentration was highest mid-season when compared with earlier in the season or 
      to the non-breeding period. For nest-box residents, GnIH-ir soma size and peptide 
      concentration were higher during the middle of the breeding season than earlier 
      in the breeding season, although residence in the nest box was not related to 
      GnRH-I-ir variables. Our results confirm that previously reported changes in cell 
      abundance mimic changes we see in GnRH-I and GnIH-ir soma size and our proxy for 
      peptide concentration. However, investigating changes in the soma of GnRH-I-ir 
      cells revealed a peak in size during the middle of the breeding season, a change 
      not evident when solely examining data on the abundance of cells. We also report 
      that GnRH-I- and GnIH-ir soma size and our proxy for peptide concentration 
      positively co-varied with each other and, in males, were positively correlated 
      with testosterone. In summary, we offer a higher resolution of understanding of 
      the function of GnRH-I and GnIH during the breeding period of European starlings.
CI  - (c) The Author 2015. Published by Oxford University Press on behalf of the Society 
      for Integrative and Comparative Biology. All rights reserved. For permissions 
      please email: journals.permissions@oup.com.
FAU - Amorin, Nelson
AU  - Amorin N
AD  - Department of Integrative Biology, University of California, Berkeley, CA 94720, 
      USA.
FAU - Calisi, Rebecca M
AU  - Calisi RM
AD  - *Department of Biology, Barnard College, Columbia University, New York, NY 10027, 
      USA; rcalisi@barnard.edu.
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20150614
PL  - England
TA  - Integr Comp Biol
JT  - Integrative and comparative biology
JID - 101152341
RN  - 0 (Avian Proteins)
RN  - 0 (Hypothalamic Hormones)
RN  - 33515-09-2 (Gonadotropin-Releasing Hormone)
SB  - IM
MH  - Animals
MH  - Avian Proteins/*genetics/metabolism
MH  - Female
MH  - Gonadotropin-Releasing Hormone/genetics/metabolism
MH  - Hypothalamic Hormones/*genetics/metabolism
MH  - Male
MH  - *Reproduction
MH  - Seasons
MH  - Starlings/*physiology
EDAT- 2015/06/17 06:00
MHDA- 2016/11/09 06:00
CRDT- 2015/06/17 06:00
PHST- 2015/06/17 06:00 [entrez]
PHST- 2015/06/17 06:00 [pubmed]
PHST- 2016/11/09 06:00 [medline]
AID - icv063 [pii]
AID - 10.1093/icb/icv063 [doi]
PST - ppublish
SO  - Integr Comp Biol. 2015 Aug;55(2):332-42. doi: 10.1093/icb/icv063. Epub 2015 Jun 
      14.