Butman B T, Obika M, Tchen T T, Taylor J D
J Exp Zool. 1979 Apr;208(1):17-34. doi: 10.1002/jez.1402080104.
Hormone-induced pigment translocation studies were conducted at both the light and electron microscopic levels on cultured dermal iridophores from the Mexican leaf frog, Pachymedusa dacnicolor. Two distinct types of dermal iridophores were characterized which differed in (1) their in vivo locations, (2) their overall morphologies in vitro, (3) their responses to alpha-MSH, ACTH, c-AMP or theophylline, (4) their physical alterations of light, and (5) certain ultrastructural features. One iridophore (Type I) was found to be physiologically responsive to the above hormones or agents by a reversible retraction of cellular processes and a thickening of the cell body, an event which is inhibited by cytochalasin B. The other iridophore (Type II) appeared to be unresponsive. Type I iridophores contain cube-like pigmentary organelles, refractosomes, while Type II iridophores contain larger, bar-shaped refractosomes. In addition, both iridophore types contain 60 and 100 A microfilaments as well as microtubules. By in large, micorfilaments were found within microvilli, beneath and parallel to the plasma membrane and in the perinuclear region. Occasionally, bundles of 100 A microfilaments were found between layers of refractosomes in Type I iridophores. These results are discussed in relation to hormone-induced changes in cell shape.
在光镜和电镜水平上，对墨西哥叶蛙（Pachymedusa dacnicolor）培养的真皮虹彩细胞进行了激素诱导的色素转运研究。鉴定出两种不同类型的真皮虹彩细胞，它们在以下方面存在差异：（1）体内位置；（2）体外整体形态；（3）对α-促黑素（α-MSH）、促肾上腺皮质激素（ACTH）、环磷酸腺苷（c-AMP）或茶碱的反应；（4）对光的物理改变；（5）某些超微结构特征。发现一种虹彩细胞（I型）对上述激素或试剂有生理反应，其细胞突起可逆性回缩，细胞体增厚，这一过程被细胞松弛素B抑制。另一种虹彩细胞（II型）似乎无反应。I型虹彩细胞含有立方体形的色素细胞器——折射体，而II型虹彩细胞含有更大的棒状折射体。此外，两种类型的虹彩细胞都含有60埃和100埃的微丝以及微管。大体上，微丝存在于微绒毛内、质膜下方和平行处以及核周区域。偶尔，在I型虹彩细胞的折射体层之间发现100埃的微丝束。结合激素诱导的细胞形状变化对这些结果进行了讨论。
