Application of Recapitulation Theory to Secretion of Atrial Natriuretic Peptide

1.从鳗鱼心房和心室分别分离出心钠素(ANP)和室利钠肽(VNP)，并测定了它们的氨基酸序列。此外，我们还测定了鳗鱼VNP2基因的cDNA序列。我们建立了鳗鱼ANP和VNP的放射免疫测定体系，并测定了鳗鱼血浆、心房、脑室和脑中的含量。心脏的ANP含量是VNP的3倍，而血浆VNP的含量是ANP的3倍。蛋白A-金免疫细胞化学显示许多分泌颗粒含有ANP，但含有VNP。。脑室内颗粒稀少。培养的鳗鱼心房肌细胞分泌少量心钠素到培养液中，但储存在细胞内的量很大。体外培养的心室肌细胞分泌大量的VNP，但储存的VNP很少。根据这些结果，我们推测心钠素主要在心房合成，储存在颗粒中，并在外源性刺激下分泌(调节通路)，而在脑室合成的大多数VNP很快分泌，而不储存在颗粒中(构成通路)。为了证实这一假设，我们正在进行一项脉冲追逐实验，以检测组织培养中鳗鱼心房和脑室ANP和VNP的分泌率。通过Northern印迹分析检测了ANP和VNP在鳗鱼心房和心室中的表达。在胎鼠中，ANP分别通过调节途径和组织途径从心房和脑室分泌，而成年哺乳动物的脑室不产生ANP。因此，来自鳗鱼和胎鼠的数据表明，海克尔的生物起源定律，即“个体发育是系统发育的重演”似乎适用于激素分泌模式。

1. We isolated atrial natriuretic peptide(ANP)and ventricular natriuretic peptide(VNP)from the eel atrium and ventricle, respectively and determined their amino acid seguences. We also determined cDNA sequence of eel VNP.2. We established specific radioimm unoassay systems for eel ANP and VNP, and measured the levels in eel plasma, atria, ventricles and brains. The heart contains 3-fold greater level of ANP than that of VNP, but the plasma level of VNP was 3-foldgreater than that of ANP.3. Protein A-goldimmunocytochemistry revealed many secretory granules which contain ANP, but VNP-containing. . granules in the ventricle was scarce.4. Eel atrial myocytes in culture secrete a small amount of ANP into the medium but the amount stored in the cell is large. Eelventricular myocytes in culture secrete a large amount of VNP but store little VNP.5. Based on these results, we hypothesized that ANP is principally synthesized in the atrium, stored in the granules, and secreted upon exogenous stimulus(regulatory pathway), whereas most of the VNP synthesezed in the ventricle is secreted soon without storage in the granules (constitutive pathway).6. In order to substantiate this hypotheses, we are now conducting a pulse-chase experiment using labeled ^<32>S-Cysteine to examine the rate of secreion of ANP and VNP from eel atrium and ventricle in tissue culture. We also examine the expression of mRNA of ANP and VNP in the eel atrium and ventricle using a Northern blot analysis.7. In the fetal rat, ANP is secreted from the atrium and ventricle viaregulatory pathway and constitutive pathway, respectively, although adult ventricles do not produce ANP in mammals. Thus, the data from eels and fetal rats illustrate that the Biogenic law of Haeckel, i. e., "Ontogeny is a recapitulation of phylogeny" appears to beapplicable to the mode of hormone secretion.