Spiral steroids (SS) are a newly discovered type of steroid. Originally, they were described as cardiotonic glycosides because they cross-reacted with digoxin-specific antibodies (Digoxin-Like-Materials-DLM). SS differ from the classical steroids in several ways: [a] they are steroid phosphodiester conjugates and displace digoxin from digoxin-specific antibodies, [b] in contrast to all other steroids, cholesterol is not a precursor, [c] SS have more than 21 carbon atoms; the extra atoms form a 5th ring which includes a lactone, [d] SS bind to NaK-ATPase in membranes rather than receptors in the nucleus. SS have been identified by HPLC- mass spectroscopy in extracts from mammals, birds, and oysters but were not detected in plant extracts. Overall, SS seem to be key components in regulating potassium electrolytes during pregnancy and its related diseases – specifically pre-eclampsia and necrotizing enterocolitis.

In addition to the classical steroids, which have cholesterol as a precursor, there are steroids with 7-dehydrocholesterol as a precursor. This review describes the identification of these steroids, their biosynthesis and some aspects of their function. There are three classes of these compounds, distinguished by the number of their carbon atoms, 23, 24 and 25. Each class has a spiral steroid and is a phosphodiester. Up until these investigations, no spiral steroids or steroid phosphodiesters were known. There are at least 13 compounds of which six have been purified to near homogeneity. Each one has been characterized by its mass and proposed composition. They function by regulating the NaK-ATPase. Based on the tissues in which they have been detected, each class of compound seems to regulate a different isoform of the NaK-ATPase. This is an important site of endocrine regulation.

Cardiotonic glycoside toxins, originally isolated from plants or amphibians, have been proposed as mammalian cardiotonic hormones. This paper is a review and update of the discovery of [i] a new class of steroid hormones, [ii] the path for their biosynthesis and [iii] some preliminary data on their function. The compounds are phosphoester conjugates and share a characteristic structural feature, a lactone ring, with [a] one class of synthetic potassium sparing diuretics and with [b] plant and amphibian cardiotonic steroids. Purification was initially monitored by cross reaction with steroid sulfate assays and later with digoxin-specific assays. Six compounds were purified by HPLC to near homogeneity and characterized by Tandem mass spectroscopy (MS-MS) and 31P-NMR. Three were digoxin-like materials (DLM) with 23 carbon atoms. The two extra carbon atoms form a spiral lactone E-ring. Several additional spiral lactones have been identified by MS-MS. In a pilot study, based on MS analysis, we evaluated phosphocholine steroid levels in individual serum samples in patients with pre-eclampsia (n=20). The control group of normotensive pregnant women (n=20) was used to estimate the mean and standard deviation. Twelve of the women with pre-eclampsia had a z-score over 2 for at least one of the four phosphocholine steroids. In contrast, only 1 sample from the normotensive women had a z-score over 2. The observation that there are two patterns, one with elevated phosphocholine steroid levels and one without the elevation, suggests that there may be two different underlying causes of pre-eclampsia. We now need to extend the study to determine which pattern predicts progression to life-threatening hypertension in pregnant women. This pilot study illustrates that it is possible to evaluate individual endogenous cardiotonic hormones without relying on antibodies developed to plant or amphibian toxins.