Size-dependent, sex-dependent and seasonal changes in insulin-lige growth-factor-I in the loggerhead sea turtle

General and Comparative Endocrinology
By: , and 

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Abstract

This study examines size-dependent, sex-dependent, and seasonal fluctuations in plasma insulin-like growth factor-I (IGF-I) concentrations in loggerhead sea turtles (Caretta caretta). Loggerhead turtles (n = 158) were captured in shrimp trawler nets during a 12-month survey in Cape Canaveral Channel, Florida. Plasma samples were analyzed using a validated heterologous radioimmunoassay. Large turtles (>75 cm straight-line carapace length) had significantly higher plasma IGF-I concentrations than small turtles (⩽75 cm; P < 0.0001). Plasma IGF-I concentrations did not vary seasonally in small turtles, but large turtles had significantly higher plasma IGF-I concentrations during the spring and summer months (P < 0.005). Within the large turtles, adult males had significantly lower IGF-I concentrations than females and subadult males (P < 0.05). These results and a review of loggerhead turtle natural history suggest that the seasonal fluctuations in plasma IGF-I of adult turtles are due to elevated IGF-I levels in reproductively active female turtles. Further research is needed to examine correlations between reproductive activities and plasma IGF-I concentrations in reptiles.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Size-dependent, sex-dependent and seasonal changes in insulin-lige growth-factor-I in the loggerhead sea turtle
Series title General and Comparative Endocrinology
DOI 10.1006/gcen.1995.1063
Volume 98
Year Published 1995
Language English
Publisher Elsevier
Contributing office(s) Florida Integrated Science Center
Description 8 p.
First page 219
Last page 226
Online Only (Y/N) N
Additional Online Files (Y/N) N
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