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大鼠垂体前叶前强啡肽产物对性腺类固醇环境变化的反应。

Response of rat pituitary anterior lobe prodynorphin products to changes in gonadal steroid environment.

作者信息

Molineaux C J, Hassen A H, Rosenberger J G, Cox B M

出版信息

Endocrinology. 1986 Nov;119(5):2297-305. doi: 10.1210/endo-119-5-2297.

Abstract

The total content of rat pituitary anterior lobe (AL) immunoreactive (ir) dynorphin A (ir-Dyn A) and ir-dynorphin B (Dyn B) increased in male rats between 15 and 58 days of age, but there was little alteration in the concentration of ir-Dyn A or B expressed relative to protein content. Adult rats (90 days of age) had lower concentrations of these peptide immunoreactivities in the AL. Castration of 58-day-old male rats produced a testosterone-reversible loss of ir-Dyn A and B by 50-60% 3 days after surgery. Thereafter, the levels of these peptides gradually increased to 2.5 times the levels found in control animals at 1 month after castration. These effects of castration on AL dynorphin were not seen in 15-day-old rats and were much less marked in adults. Similar changes were seen in the levels of other prodynorphin products, alpha- and beta-neo-endorphin (ir-alpha-nEnd and ir-beta-nEnd), and ir-[Leu5]enkephalin (ir-LE). Administration of testosterone (100 micrograms/100 g BW) to castrated rats for 2 days largely prevented the drop in the levels of AL ir-Dyn A and B. Ovariectomy produced an increase in the levels of ir-Dyn A, Dyn B, alpha-nEnd, beta-nEnd, and LE 2 weeks after surgery, but, in contrast to castration, no significant decrease was seen 3 days after ovariectomy. These changes in AL content of dynorphin-related peptides after castration or ovariectomy directly reflect those previously reported for AL content of LH. The mechanisms regulating storage (and perhaps secretion) of AL peptides derived from prodynorphin may be similar to those regulating storage and secretion of LH and FSH in rat AL. AL ir-LE could potentially arise from proenkephalin A or prodynorphin (proenkephalin B). Ir-LE levels in AL were approximately 10 times higher than the levels of ir-[Met5]-enkephalinyl-Arg-Gly-Leu (ME-RGL) in male rat AL, and changes in ir-LE content after castration were very similar to those observed in other prodynorphin-derived peptides, but different from the effects of castration on ir-ME-RGL. It is possible that prodynorphin is a major source of AL ir-LE.

摘要

在15至58日龄的雄性大鼠中,垂体前叶(AL)免疫反应性(ir)强啡肽A(ir-Dyn A)和ir-强啡肽B(Dyn B)的总含量增加,但相对于蛋白质含量而言,ir-Dyn A或B的浓度变化不大。成年大鼠(90日龄)垂体前叶中这些肽免疫反应性的浓度较低。对58日龄雄性大鼠进行去势手术后3天,ir-Dyn A和B的含量可逆性减少50 - 60%,减少量与睾酮有关。此后,这些肽的水平在去势后1个月逐渐增加至对照动物的2.5倍。去势对垂体前叶强啡肽的这些影响在15日龄大鼠中未观察到,在成年大鼠中也不明显。其他前强啡肽产物α-和β-新内啡肽(ir-α-nEnd和ir-β-nEnd)以及ir-[亮氨酸5]脑啡肽(ir-LE)的水平也出现了类似变化。给去势大鼠注射睾酮(100微克/100克体重)2天,在很大程度上可防止垂体前叶ir-Dyn A和B水平的下降。卵巢切除术后2周,ir-Dyn A、Dyn B、α-nEnd、β-nEnd和LE的水平升高,但与去势不同的是,卵巢切除术后3天未观察到显著下降。去势或卵巢切除术后垂体前叶中强啡肽相关肽含量的这些变化直接反映了先前报道的促黄体生成素(LH)在垂体前叶中的含量变化。调节源自前强啡肽的垂体前叶肽储存(可能还有分泌)的机制可能与调节大鼠垂体前叶中LH和促卵泡激素(FSH)储存和分泌的机制相似。垂体前叶ir-LE可能源自前脑啡肽A或前强啡肽(前脑啡肽B)。雄性大鼠垂体前叶中ir-LE的水平比ir-[甲硫氨酸5]脑啡肽-精氨酸-甘氨酸-亮氨酸(ME-RGL)的水平高约10倍,去势后ir-LE含量的变化与其他源自前强啡肽的肽所观察到的变化非常相似,但与去势对ir-ME-RGL的影响不同。前强啡肽有可能是垂体前叶ir-LE的主要来源。

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