Pituitary LH content and plasma LH levels following daily GnRH analogue treatment in male red-winged blackbirds (Agelaius phoeniceus).
1. During the 14-day treatment period, plasma LH levels following GnRH analogue (GnRH-A) injections (10.0 micrograms) were significantly reduced after the 6th and the 14th injection. 2. One day post-treatment, the LH pituitary content was significantly reduced in GnRH-A-treated redwings compared to saline-injected controls. 3. Pituitary LH content was significantly higher in GnRH-A treated birds compared to control birds 14 and 28 days post-treatment and plasma LH levels were similar in both groups. 4. Hypersecretion of LH following GnRH-A injections appears to reduce pituitary LH content, acting as a stimulus for its synthesis. 5. These results suggest a higher LH synthesis and storage in the pituitary gland of the GnRH-A-treated birds compared to the control birds during the post-treatment period.
Department of Biology, Faculty of Science, University of Sherbrooke, Qc, Canada.
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D
Lacombe
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Cyr
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Matton
D000818:Animals; D001717:Birds / Q000097:blood / Q000378:metabolism*; D007987:Gonadotropin-Releasing Hormone / Q000031:analogs & derivatives* / Q000494:pharmacology; D007986:Luteinizing Hormone / Q000097:blood / Q000378:metabolism*; D008297:Male; D010902:Pituitary Gland / Q000187:drug effects* / Q000378:metabolism; D013997:Time Factors; D017329:Triptorelin Pamoate / Q000031:analogs & derivatives*
D017329:Triptorelin Pamoate; D007987:Gonadotropin-Releasing Hormone; C019176:Tryptal; D007986:Luteinizing Hormone