Circulating hormone levels in hatchlings of green turtle, chelonia mydas, from ras al-hadd reserve, Oman

Abstract EN

Post-hatching levels of plasma estradiol (E2), Progesterone (Pro), Testosterone (T), Luteinizing Hormone (LH), Follicle-Stimulating Hormone (FSH) and thyroxin (T4) were monitored in hatchlings of Green Turtle, Chelonian mydas immediately after emergence.

Eggs were collected at random from 5 nests.

The eggs were placed in incubators 16 hr.

after ovipositor set at 26-27oC for male producing hatchlings and at 30-31oC for female producing hatchlings.

Blood was collected after sacrifice.

Chemiluminescence immunoassay was used for determination of plasma hormone levels, using Beckman Coulter Access-2-immunoassay and reagents (Beckman Coulter, Inc.).

Sex was determined from histological examination of gonads.

In males, plasma T levels were positively correlated with temperature (rho = 0.67, P<0.001).

However, plasma E2 levels were negatively correlated but not strongly with temperature (rho = -0.396, P<0.05) and there was a weak correlation between plasma LH levels and temperatures (rho = 0.38, P<0.05).

Also in the males, there was no correlation between temperature and either plasma Pro or T4 levels.

In females, there was no correlation between temperature and any of the hormones.

In addition, there was no significant difference in plasma concentrations of T, Pro, LH or T4 between sexes.

However, plasma E2 concentration was significantly higher in males (P<0.05).

FSH was undetectable in plasma from both sexes.

The significance of these findings will be discussed.