Moy J A, Lawson D M
Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan 48201.
Endocrinology. 1988 Sep;123(3):1314-9. doi: 10.1210/endo-123-3-1314.
Previous observations in our laboratory indicated that rat serum samples being bioassayed for PRL with the use of Nb2 lymphoma cells produced mitogenic responses greater than maximally effective doses of purified rat PRL. The present studies were conducted to confirm these observations and to determine the possible serum factor or factors responsible for the potentiated response of serum. Twenty five rat serum pools prepared from blood samples obtained from lactating, ovariectomized, and steroid-treated rats were assayed in duplicate aliquots of 0.3-50 microliter against NIDDK-RP-1 rat PRL (11 IU/mg) by the Nb2 bioassay in Fischer's Medium containing 10% horse serum and by conventional double antibody RIA. The mitogenic response of 18 of the 25 pools were clearly greater than the response to standard rat PRL when included in the bioassay at 10-50 microliter/ml of cells. When less than 10 microliter serum pools were assayed, parallelism to the standard was observed; but the concentrations of PRL determined by bioassay were 82 +/- (SE) 4% of the levels determined by RIA in samples from ovariectomized, steroid-treated rats stored for two or four weeks and 62 +/- 2% in samples from lactating rats stored for 3-6 months. Horse serum and hypophysectomized rat serum also potentiated the mitogenic responses to 1 or 5 ng standard rat PRL when added at 10-150 microliter/ml of culture medium that already contained 100 microliter (10%) horse serum. No potentiation of the RIA was observed with rat or horse serum. Insulin, proinsulin, or C peptide of proinsulin (0.02 ng-2 micrograms/ml); fibroblast growth factor, nerve growth factor, epidermal growth factor, insulin-like growth factors I or II (0.002-200 ng/ml), T cell growth factor (TCGF) (0.0002-20 half-maximal units/ml) or platelet-derived growth factor (0.002-10 half-maximal units) did not potentiate the responses to 1 or 5 ng/ml standard rat PRL. Of the growth factors tested, only TCGF was mitogenic to Nb2 cells when placed alone in the medium, but this mitogenic effect of TCGF was not potentiated by horse serum. We conclude that serum can potentiate the mitogenic effect of PRL on Nb2 cells grown in Fischer's medium.
我们实验室之前的观察表明，在用Nb2淋巴瘤细胞对大鼠血清样本进行催乳素生物测定时，所产生的促有丝分裂反应大于纯化大鼠催乳素的最大有效剂量。进行本研究是为了证实这些观察结果，并确定可能导致血清增强反应的一种或多种血清因子。从泌乳、去卵巢和接受类固醇处理的大鼠采集的血样中制备了25个大鼠血清池，将0.3 - 50微升的重复等分试样，在含有10%马血清的Fischer培养基中，通过Nb2生物测定法，针对NIDDK - RP - 1大鼠催乳素（11 IU/mg）进行检测，并采用传统双抗体放射免疫分析法（RIA）。在生物测定中，当25个血清池中的18个以10 - 50微升/毫升细胞的浓度加入时，其促有丝分裂反应明显大于对标准大鼠催乳素的反应。当检测小于10微升的血清池时，观察到与标准的平行性；但通过生物测定法测定的催乳素浓度，在储存两周或四周的去卵巢、接受类固醇处理的大鼠样本中，是RIA法测定水平的82±（标准误）4%，在储存3 - 6个月的泌乳大鼠样本中为62±2%。当以10 - 150微升/毫升的浓度添加到已含有100微升（10%）马血清的培养基中时，马血清和垂体切除大鼠血清也增强了对1或5纳克标准大鼠催乳素的促有丝分裂反应。未观察到大鼠或马血清对RIA有增强作用。胰岛素、胰岛素原或胰岛素原的C肽（0.02纳克 - 2微克/毫升）；成纤维细胞生长因子、神经生长因子、表皮生长因子、胰岛素样生长因子I或II（0.002 - 200纳克/毫升）、T细胞生长因子（TCGF）（0.0002 - 20个半数最大单位/毫升）或血小板衍生生长因子（0.002 - 10个半数最大单位）均未增强对1或5纳克/毫升标准大鼠催乳素的反应。在所测试的生长因子中，只有TCGF单独置于培养基中时对Nb2细胞有促有丝分裂作用，但马血清并未增强TCGF的这种促有丝分裂作用。我们得出结论，血清可增强催乳素对在Fischer培养基中生长的Nb2细胞的促有丝分裂作用。
