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

哈德良腺在三百年前的1694年首次被报道。它具有视网膜外光感受器、调节昼夜节律及其信息素作用等多种功能，此外还具有作为润滑剂的脂质排泄作用。这个腺体是研究昼夜节律的一个有趣的模式器官。在本研究中，我们发现了一种新的多肽生长因子，命名为“哈德氏腺源性生长因子（HGDGF）”，通过TSKgel DEAE-5PW， Blue Sepharose CL-6B和Superose 12的柱层析，从豚鼠哈德氏腺中纯化了约43,000倍，具有明显的同质性。该生长因子分别在TSKgel DEAE-5PW中以0.20-0.35 M MaCl洗脱，以0.15-0.80 M NaCl线性梯度洗脱，在Blue Sepharose CL-6B中以2.20 M NaCl洗脱。采用^3H -胸苷掺入法测定HGDGF对人胚胎细胞（TIG-3）的活性，刺激48 h呈线性和剂量依赖性。最终收益率约为10%。经sds -聚丙烯酰胺凝胶电泳和分子筛柱层析测定，纯化后的生长因子分子量约为14000。HGDGF对SH试剂和乙酸处理不稳定。胰酶消化和煮沸均降低了HGDGF的活性。pI是5.1。该因子刺激TIG-3细胞的增殖，但对需要成纤维细胞生长因子（FGF）生长的K2T1细胞没有影响。HGDGF似乎不同于其他生长因子，这表明它是一种以前未被描述的生长因子。这种生长因子的特性将为我们理解昼夜节律的调节提供重要信息。

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.