Zhu Y, Thomas P
University of Texas at Austin, Marine Science Institute, Port Aransas 78373, USA.
Gen Comp Endocrinol. 1995 Sep;99(3):275-88. doi: 10.1006/gcen.1995.1111.
A specific radioimmunoassay (RIA) for measurement of red drum (Sciaenops ocellatus) somatolactin (rdSL) was developed using somatolactin purified from red drum pituitaries and antisera to rdSL raised in rabbits. The rdSL antisera specifically bound to cells in the pars intermedia bordering the neurohypophysis in red drum and Atlantic croaker (Micropogonias undulatus) pituitaries. These cells correspond to the periodic acid-Schiff-positive cells and are distinct from the lead-hematoxylin-positive cells which include the alpha-melanocyte-stimulating hormone (alpha-MSH) cells. No cross-reaction in the rdSL RIA was observed with red drum growth hormone (GH), prolactin (PRL), recombinant tuna GH, Atlantic croaker maturational GTH (GTH II), human GH, PRL, human follicle-stimulating hormone alpha subunit (FSH alpha), bovine FSH beta subunit, human adrenocorticotropic hormone, synthetic mammalian alpha-MSH, beta-MSH, gamma-MSH, delta-MSH, or cortisol. Dilution curves of plasma and pituitary extracts from red drum and Atlantic croaker were parallel to the rdSL standard curve. The assay had a sensitivity of 0.14 ng/ml plasma when 100 microliters plasma was assayed. SL levels in juvenile red drum ranged from 0.5 to greater than 32 ng/ml in plasma and from 0.5 to 13.5 micrograms/mg tissue in pituitaries. No significant elevation in plasma SL levels was observed in either red drum or Atlantic croaker exposed to acute stressors. In contrast, plasma SL levels were significantly higher in both red drum and Atlantic croaker exposed to dark backgrounds than in those exposed to light backgrounds. These results provide the first evidence that SL may play a role in adaptation to dark backgrounds in sciaenid fishes.
利用从红鼓鱼垂体中纯化得到的生长抑素和在兔体内产生的抗红鼓鱼生长抑素抗血清，开发了一种用于测定红鼓鱼（眼斑拟石首鱼）生长抑素（rdSL）的特异性放射免疫分析法（RIA）。rdSL抗血清与红鼓鱼和大西洋鲷（细纹鳓）垂体中与神经垂体相邻的中间部细胞特异性结合。这些细胞对应于过碘酸-希夫阳性细胞，与包括α-黑素细胞刺激素（α-MSH）细胞在内的铅苏木精阳性细胞不同。在rdSL RIA中未观察到与红鼓鱼生长激素（GH）、催乳素（PRL）、重组金枪鱼GH、大西洋鲷成熟促性腺激素（GTH II）、人GH、PRL、人促卵泡激素α亚基（FSHα）、牛FSHβ亚基、人促肾上腺皮质激素、合成哺乳动物α-MSH、β-MSH、γ-MSH、δ-MSH或皮质醇发生交叉反应。红鼓鱼和大西洋鲷血浆及垂体提取物的稀释曲线与rdSL标准曲线平行。当检测100微升血浆时，该分析方法的灵敏度为0.14纳克/毫升血浆。幼龄红鼓鱼血浆中SL水平在0.5至大于32纳克/毫升之间，垂体中为0.5至13.5微克/毫克组织。在暴露于急性应激源的红鼓鱼或大西洋鲷中，均未观察到血浆SL水平显著升高。相比之下，暴露于黑暗背景下的红鼓鱼和大西洋鲷的血浆SL水平均显著高于暴露于明亮背景下的鱼。这些结果首次证明，SL可能在鲹科鱼类适应黑暗背景中发挥作用。
