Funder J W, Adam W R
Endocrinology. 1981 Jul;109(1):313-5. doi: 10.1210/endo-109-1-313.
19-Nor progesterone (19-nor P) has previously been shown to have a approximately 3-fold higher affinity for mineralocorticoid receptors than progesterone (P), its C-19 methylated parent steroid; in contrast, 19-nor aldosterone has less than 1% the mineralocorticoid receptor affinity of aldosterone. In the present study we have compared P and 19-nor P, in terms of their mineralocorticoid activity in an adrenalectomized rat urinary K+/Na+ bioassay system. Progesterone, as previously has been shown, is a mineralocorticoid antagonist with no agonist activity. In contrast, 19-nor progesterone is a full mineralocorticoid agonist, with no discernible antagonist activity. Loss of the C19 methyl is thus followed by profound changes in mineralocorticoid activity (aldosterone: agonist to inactive; progesterone: antagonist to agonist). In the light of the recent demonstration of C19 demethylation by the kidney, such changes in mineralocorticoid activity may be implicated in currently unexplained syndromes of sodium retention.
19-去甲孕酮（19-nor P）先前已被证明对盐皮质激素受体的亲和力比其C-19甲基化母体类固醇孕酮（P）高约3倍；相比之下，19-去甲醛固酮的盐皮质激素受体亲和力不到醛固酮的1%。在本研究中，我们在肾上腺切除大鼠尿钾/钠生物测定系统中比较了P和19-nor P的盐皮质激素活性。如先前所示，孕酮是一种盐皮质激素拮抗剂，无激动剂活性。相比之下，19-去甲孕酮是一种完全的盐皮质激素激动剂，无明显的拮抗剂活性。因此，C19甲基的缺失伴随着盐皮质激素活性的深刻变化（醛固酮：从激动剂变为无活性；孕酮：从拮抗剂变为激动剂）。鉴于最近肾脏中C19去甲基化的证明，盐皮质激素活性的这种变化可能与目前无法解释的钠潴留综合征有关。
