Harderian Gland as a Model Organ for Study of Circadian Rhythm.

哈德氏腺在三百年前的1694年首次被报道。除了作为润滑剂排泄脂质外，它还具有多种功能，如视网膜外光感受器、调节昼夜节律及其信息素效应。该腺体是研究昼夜节律的一个有趣的模型器官。在本研究中，我们发现了一种新的多肽生长因子，命名为“Harderian腺体衍生生长因子(HGDGF)”，经TSKGel DEAE-5PW、Blue SepharoseCL-6B和Superose 12柱层析从豚鼠Harderian腺体中纯化了约43,000倍。该生长因子分别在0.20-0.35 M Macl和2.20 M NaC l-NaC l从Blue SephoseCL-6B上洗脱。HGDGF对人胚胎细胞(TIG-3)作用48h后，用~(3 H)TdR掺入法测定HGDGF对人胚胎细胞(TIG-3)的活性，呈线性和剂量依赖性。最终收率约为10%。经十二烷基硫酸钠-聚丙烯酰胺凝胶电泳法和分子筛柱层析测定，纯化的生长因子的相对分子质量约为14,000。HGDGF对SH试剂和冰醋酸不稳定。胰酶消化和煮沸均可降低HGDGF的活性。其等电点为5.1。该因子可促进TIG-3细胞的增殖，但对需要成纤维细胞生长因子的K2T1细胞无影响。HGDGF似乎与其他生长因子不同，提示它是一种以前未被描述的生长因子，该生长因子的特征将为我们理解昼夜节律的调节提供重要的信息。

Harderian gland was first reported in 1694, three hundred years ago. It has several functions as an extraretinal photoreceptor, regulation of the circadian rhythm and its pheromonal effect, in addition to the excretion of lipids as lubricant. This gland is an interesting model organ for the study of circadian rhythm.In the present study, we found a novel polypeptide growth factor, named "Harderian gland-derived growth factor (HGDGF)" , which has been purified approximately 43,000-fold, to apparent homogeneity, from guinea pig Harderian gland by column chromatographies on TSKgel DEAE-5PW, Blue Sepharose CL-6B, and Superose 12. This growth factor was eluted from TSKgel DEAE-5PW at 0.20-0.35 M MaCl, with a linear gradient of 0.15-0.80 M NaCl, and at 2.20 M NaCl from Blue Sepharose CL-6B, respectively. The activity of HGDGF toward human embryonic cells (TIG-3) was quantitated by ^3H -thymidine incorporation for 48 h, which was stimulated in a linear and dose dependent manner. The final yield was approximately 10%. The purified growth factor has a molecular weight of apporximately 14,000, as determined by SDS-polyacrylamide gel electrophoresis and also by molecular sieve column chromatography. HGDGF was labile to treatment with SH reagents or acetic acid. Both trypsin digestion and boiling decreased the activity of HGDGF. Its pI was 5.1. This factor stimulated the multiplication of TIG-3 cells but had no effect on K2T1 cells which require fibroblast growth factor (FGF) for growth. HGDGF appears to differ from other growth factors, suggesting that it is a previously undescribed growth factor.The characterization of this growth factor will give us important informations in the understanding of the regulation of circadian rhythm.