Comparison of Gonadotropin- and Catecholamine-Induced Alterations of the Adenylyl Cyclase G-Proteins in Rabbit Corpora Lutea
It is well established that the corpus luteum in rabbits contains an adenylyl cyclase that is responsive to both LH/hCG and catecholamines (1–4), and that both these hormones activate the same adenylyl cyclase (3,4). Earlier studies have shown that exposure of corpora lutea or ovarian tissues to either LH/hCG or catecholamines leads to refractoriness of the adenylyl cyclase in these tissues (5,6), and that this refractoriness is in part reflective of changes and/or loss in receptor function (7,8). Guanine nucleotide-binding regulatory proteins (G-proteins) transduce hormone-receptor occupancy to the catalytic subunit of adenylyl cyclase, hence playing a crucial role in signal transduction (9). Therefore, the present study was undertaken to assess changes in luteal adenylyl cyclase activity and G-protein function, after injection of either hCG or epinephrine (EPI) to pseudopregnant female rabbits. In this study, we present data that show alterations in G-proteins of the rabbit luteal adenylyl cyclase system after hormone treatment.
KeywordsAdenylyl Cyclase Adenylyl Cyclase Activity Heterologous Desensitization Adenylyl Cyclase System Basal Adenylyl Cyclase Activity
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