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

哈氏腺最早于1694年被报道，距今已有300年。除了作为润滑剂排泄脂质之外，它还具有作为视网膜外感光器、调节昼夜节律及其信息素效应的多种功能。在本研究中，我们发现了一种新的多肽生长因子，命名为“哈氏腺衍生生长因子（HGDGF）”，它已被纯化约43,000倍，表观同质性，从豚鼠哈氏腺TSKgel DEAE-5 PW，Blue Sepharose CL-6 B和Superose 12柱层析。分别以0.20-0.35 M MaCl、0.15-0.80 M NaCl线性梯度和2.20 M NaCl从TSKgel DEAE-5 PW和Blue Sepharose CL-6 B中洗脱该生长因子。用^3H -胸苷掺入法定量测定HGDGF对人胚胎细胞（TIG-3）的活性，并以线性和剂量依赖的方式刺激48 h。最终产率约为10%。经SDS-聚丙烯酰胺凝胶电泳和分子筛柱层析测定，纯化的生长因子的分子量约为14，000。HGDGF对SH试剂和乙酸不敏感。胰蛋白酶消化和煮沸均降低HGDGF的活性。其pI为5.1。该因子刺激了TIG-3细胞的增殖，但对生长需要成纤维细胞生长因子（FGF）的K2 T1细胞没有影响。HGDGF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，它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.