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Early spring sex differences in luteinizing hormone response to gonadotropin releasing hormone in co-occurring resident and migrant dark-eyed juncos ( Junco hyemalis )

View Article: PubMed Central - PubMed

ABSTRACT

In early spring female juncos vary in LH following repeated stimulation with GnRH.

Resident and migrant males do not vary in LH.

Suggests the pituitary as a critical point of control for reproductive timing.

Sex difference suggests selection shaped responsiveness at critical time points.

Sex difference suggests selection shaped responsiveness at critical time points.

No MeSH data available.


Individual response to multiple GnRH injections: Variation among individuals was observed in their response to repeated stimulation with GnRH in both males (A) and females (B). Individual responses have been provided with differing colors to aid in observation of trends, with green lines indicating continued elevation to repeated stimulation, blue lines indicating a plateau in LH levels between the 1st and 3rd injection with GnRH, and red lines indicating a drop in LH levels between initial stimulation with GnRH and repeated simulation. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)
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f0015: Individual response to multiple GnRH injections: Variation among individuals was observed in their response to repeated stimulation with GnRH in both males (A) and females (B). Individual responses have been provided with differing colors to aid in observation of trends, with green lines indicating continued elevation to repeated stimulation, blue lines indicating a plateau in LH levels between the 1st and 3rd injection with GnRH, and red lines indicating a drop in LH levels between initial stimulation with GnRH and repeated simulation. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

Mentions: The results of our model (Table 2) revealed a significant main effect of blood sampling time (F2,97.9 = 125.17, p < 0.01); post-hoc comparisons revealed elevated LH levels following a single GnRH injection compared with baseline levels in all groups (all p < 0.01), and elevated LH levels following 3 injections compared with baseline levels in all groups (all at p < 0.02). Further, a main effect of resident/migrant status was observed (F1,51.9 = 9.13, p < 0.01), with residents overall displaying elevated LH levels compared with migrants. Variation in how individuals respond to repeated GnRH stimulation was high, with some individuals continuing to elevate LH levels between the first and third GnRH injection, while other individuals leveled off or showed reductions in circulating LH levels between the samples collected following first and third GnRH injection (Fig. 3).


Early spring sex differences in luteinizing hormone response to gonadotropin releasing hormone in co-occurring resident and migrant dark-eyed juncos ( Junco hyemalis )
Individual response to multiple GnRH injections: Variation among individuals was observed in their response to repeated stimulation with GnRH in both males (A) and females (B). Individual responses have been provided with differing colors to aid in observation of trends, with green lines indicating continued elevation to repeated stimulation, blue lines indicating a plateau in LH levels between the 1st and 3rd injection with GnRH, and red lines indicating a drop in LH levels between initial stimulation with GnRH and repeated simulation. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)
© Copyright Policy - CC BY
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5036536&req=5

f0015: Individual response to multiple GnRH injections: Variation among individuals was observed in their response to repeated stimulation with GnRH in both males (A) and females (B). Individual responses have been provided with differing colors to aid in observation of trends, with green lines indicating continued elevation to repeated stimulation, blue lines indicating a plateau in LH levels between the 1st and 3rd injection with GnRH, and red lines indicating a drop in LH levels between initial stimulation with GnRH and repeated simulation. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)
Mentions: The results of our model (Table 2) revealed a significant main effect of blood sampling time (F2,97.9 = 125.17, p < 0.01); post-hoc comparisons revealed elevated LH levels following a single GnRH injection compared with baseline levels in all groups (all p < 0.01), and elevated LH levels following 3 injections compared with baseline levels in all groups (all at p < 0.02). Further, a main effect of resident/migrant status was observed (F1,51.9 = 9.13, p < 0.01), with residents overall displaying elevated LH levels compared with migrants. Variation in how individuals respond to repeated GnRH stimulation was high, with some individuals continuing to elevate LH levels between the first and third GnRH injection, while other individuals leveled off or showed reductions in circulating LH levels between the samples collected following first and third GnRH injection (Fig. 3).

View Article: PubMed Central - PubMed

ABSTRACT

In early spring female juncos vary in LH following repeated stimulation with GnRH.

Resident and migrant males do not vary in LH.

Suggests the pituitary as a critical point of control for reproductive timing.

Sex difference suggests selection shaped responsiveness at critical time points.

Sex difference suggests selection shaped responsiveness at critical time points.

No MeSH data available.