Clerico A, Paci A, Del Chicca M G, Biver P, Giampietro O
Istituto di Fisiologia Clinica del CNR, Pisa, Italy.
Clin Chem. 1992 Apr;38(4):504-6.
We measured the concentration of endogenous digitalis-like factors (EDLFs) in milk or colostrum of women during nursing on different days after delivery. EDLF concentrations were assayed by a solid-phase RIA involving antidigoxin antibodies and by a radioreceptor assay (RRA) involving human placenta Na+/K(+)-ATPase. The mean (SD) EDLF concentrations as measured by RIA were 35.6 (19.4) ng of digoxin equivalents per liter in milk samples (n = 37) and 61.3 (12.5) ng/L in colostrum samples (n = 5); the mean EDLF concentration as measured by RRA in milk samples (n = 11) was 573 (717) ng/L (range 0-2098). EDLF concentration in milk is greater than circulating concentrations in healthy adults but is comparable with serum concentration in the third trimester of pregnancy. In milk and serum samples (n = 8) collected at the same time, heating and (or) extracting with Sep-Pak C18 cartridges before the RIA produced significantly different EDLF values from those in untreated serum (P less than 0.001) and milk (P = 0.035). EDLF in milk appeared to be not bound or weakly bound to milk protein, as indicated by the fact that boiling did not increase the digoxin-like immunoreactivity.
我们测定了产后不同时间哺乳女性乳汁或初乳中内源性洋地黄样因子（EDLFs）的浓度。采用涉及抗地高辛抗体的固相放射免疫分析法（RIA）以及涉及人胎盘钠钾ATP酶的放射受体分析法（RRA）对EDLFs浓度进行测定。通过RIA测得的乳汁样本（n = 37）中EDLF的平均（标准差）浓度为每升35.6（19.4）纳克地高辛当量，初乳样本（n = 5）中为61.3（12.5）纳克/升；通过RRA测得的乳汁样本（n = 11）中EDLF的平均浓度为573（717）纳克/升（范围为0 - 2098）。乳汁中EDLF的浓度高于健康成年人的循环浓度，但与妊娠晚期的血清浓度相当。在同时采集的乳汁和血清样本（n = 8）中，RIA检测前加热和（或）用Sep - Pak C18柱提取后，所得EDLF值与未处理的血清（P < 0.001）和乳汁（P = 0.035）中的值有显著差异。乳汁中的EDLF似乎未与乳蛋白结合或仅微弱结合，因为煮沸并未增加地高辛样免疫反应性。
