- 作者: 許織雲;于?文;江建勳
- 中文摘要: ?基類固醉?脊椎動物性腺及腎上腺所分泌之?泌素,其合成步驟中之?化作用可被 Metopirone 所抑制。今以 Metopirone處理牛蛙蝌蚪,研討該藥物對蝌蚪性腺分化之影響。 處理五個月後,鏡檢性腺切片,研判性腺之分化。又用組織化學法檢?性腺及腎上腺中Δ5-3β?基類同醇去氫?(Δ5-3β-HSD)之活性;並以Zeiss顯微分光儀測定該?活性之強度。 結果獲知本實驗所用之牛蛙蝌蚪屬性腺半分化族,其睾丸均由暫時性卵巢轉變而來。故對照組亦出現中問性別,係卵 巢退化而趨向睾丸發育。但實驗組itt種中間性別者較多。蓋因Me?叩?rone具抑制19一 C處?化?之功能,而芳香化作用 受阻,可能致使雌性素合成降低,引起卵巢退化?中間性別。由組織化學方法顯示對照組卵巢中之Δ5-3β-HSD活性 較經Metopirone處理者?強。此現象並非Metopirone之直接影響而係卵母細胞先行退化而該?乃漸消失。 實驗組蝌蚪腎上腺變?肥大,因Metopirone除阻?19一C之?化?外,尚可抑制11一C之?化作用,致腎上腺皮質 類固醇減產而引起ACTH反饋,故腎上腺肥大。 根據前人及本實驗室之報導,推測經Metopirone處理後,卵巢變性及腎上腺肥大雖同時發生,但二者互不干擾。前 者不經腦下腺之控制,而後者必需依?ACTH之機轉。故本實驗結果提示,蝌蚪卵巢變性可能?雌性素合成?驟直接受 到干擾所致。
- 英文摘要: Metopirone (M) was used as an enzyme inhibitor in hydroxysteroid biosynthesis to induce sex transformation of ovaries to testes in R. catesbeiana tadpoles. After 5 months of treatment, the tadpoles were killed for microscopic gondal examination and histochemical test for Δ5-3β-HSD activity. The experimentals had a greater proportion of degenerated ovaries than the controls and showed interrenal hyperplasia. Δ5-3β-HSD activity was greater in control than in metopirone-treated, degenerated gonads. Metopirone is generally considered as an enzyme inhibitor at 19-hydroxylation in steroidogenesis. Ovarian breakdown might have been due to decreased estrogen formation as a result of drug interference with the aromatase. It is also known that metopirone can block 11-hydroxylation, responsible for interrenal hyperplasia via the anterior pituitary. However, the two reactions of the drug in this report were independent of each other. The ovarian effect was most likely pituitary-independent, while interrenal hyperplasia depended on the pituitary. It is suggested that sex transformation in tadpoles is due to a direct disturbance in ovarian steroid synthesis without mediation through other endocrine glands.
- 中文關鍵字: --
- 英文關鍵字: --