Search

Secondary amyloidosis is a complication of diseases characterized by recurrent acute inflammation. In this study, a standardized stimulus which induced fever and inflammation was given to six normal subjects (19-24 yr old) to follow the fluctuation in concentration of serum amyloid A (SAA), the precursor of the secondary amyloid fibril protein. After a single intramuscular injection of etiocholanolone (0.3 mg/kg), blood samples were drawn twice a day for 12 days for determination of SAA by solid phase radioimmunoassay. From a base line of <100 mug/ml, the SAA concentration began rising within 12 h to a maximum value at about 48 h of 1,350-1,800 mug/ml in three males and 380-900 mug/ml in three females and returned to base line by 4-5 days. The SAA response showed a similar time response to C-reactive protein (CRP), a well-documented acute phase protein which was assayed semiquantitatively by capillary tube precipitin reaction. CRP, but not SAA, showed a quantitative correlation with the amount of fever induced by etiocholanolone. One subject exhibited a second rise in SAA and CRP concentrations after acute over-indulgence with alcohol, suggesting that acute liver damage may have caused an acute phase reaction. Thus, a controlled episode of fever and inflammation produced a prompt and prolonged elevation of SAA and CRP concentrations. Unlike SAA, CRP has not been implicated in the pathogenesis of amyloidosis, although its relationship to the P component of amyloid has recently been established.

The first chemical synthesis of 3 alpha, 7 alpha-dihydroxy-5 beta-androstan-17-one and 3 alpha-hydroxy-5 beta-androstane-7, 17-dione is reported. In this method, the 17 beta-side chain of commercial chenodesoxycholic acid was degraded in 6 steps after selective protection of the hydroxyl groups: 3 alpha-OH by a tert-butyldimethylsilyl group and 7 alpha-OH by an acetoxy group. The capacity of 3 alpha, 7 alpha-dihydroxy-5 beta-androstan-17-one and 3 alpha-hydroxy-5 beta-androstane-7, 17-dione to release a pyrogen by human leukocytes was investigated by two independent methods: supernatants from leukocytes incubated with a steroid are injected to rabbits whose fever is measured, or tested by the Limulus Test (a pyrogen detection technique). The 7-keto substituted etiocholanolone still possessed pyrogenic activity, while the 7 alpha-hydroxyl substituted one did not.

Dehydroepiandrosterone, an adrenal steroid that has been reported to be produced in subnormal amounts and found in lower plasma concentrations in women with benign and malignant breast tumors, protects cultured rat liver epithelial-like cells against aflatoxin B1-induced cytotoxicity and protects hamster embryonic fibroblasts against aflatoxin B1- and 7,12-dimethylbenz(a)anthracene-induced transformation. Related androgenic steroids show significantly less protective effect. Dehydroepiandrosterone also inhibits the rate of conversion of [3H]-7,12-dimethylbenz(a)anthracene to water-soluble metabolites by rat liver epithelial-like cells, suggesting that the steroid probably exerts its protective effect by inhibiting carcinogen activation.

A method of blood granylocyte concentration and isolation of granules from both normal and neutropenic Chediak-Higashi syndrome (CHS) patients is described. the intracellular distribution of activity for several hydrolases in CHS granulocytes differs from normal; significantly more activity is present in the cytoplasmic fraction and correspondingly less is granule-associated. Isolated CHS granules are not more sensitive to the labilizing agents vitamin A, progesterone, or etiocholanolone. Specific activities of myeloperoxidase and ss-glucuronidase in CHS granulocytes are lower than normal while alkaline phosphatase is elevated. Other lysosomal enzyme activities are normal. Lysosomal enzyme distribution and content are similar in CHS and normal mononuclear cells. The possible significance of these findings is discussed.

A quantitative structure-activity relationship (QSAR) approach by use of the minimal topological difference (MTD) method including 46 derivatives of 4-androstene-3,17-dione and 5 alpha-androstane-3,17-dione is applied to give indications about the role of the C4 = C5 double bond in competitive inhibition of human placental aromatase and about sterical requirements in steroid-aromatase interactions. The inhibitory activity is found to correlate with the sterical MTD variable, hydrophobicity, and pi-system conjugation in the A,B-ring region. A comparison of the MTD results reveals a good agreement with interpretations based on free-energy data derived from inhibition constants. By means of MM2 molecular mechanics and PCILO quantum-chemical calculations, the 4-ene structure is shown to significantly influence conformational features of C19 substituents which are important in enzymatic transformations. While 19-hydroxy-5 alpha-androstane-3,17-dione favour a conformation having the hydroxyl group in the enzyme-directed out-of-ring position, the C4 = C5 double bond energetically enables the steroid to adopt a conformation which can be hydroxylated without internal rotations. According to present theoretical findings, the 4-ene unsaturation thus exerts an indirect conformational influence by hydroxyl positioning appropriate to aromatase interactions and a direct electronic influence by pi conjugation.

Selected androgenic and nonandrogenic steroids enhance in vitro granulocytic and erythroid colony formation by mouse marrow cells, but do so by influencing either different target cells or cells in different states of cell cycle. Etiocholanolone, a naturally occurring nonandrogenic testosterone metabolite, permits cells not in active cycle to respond to colony-stimulating factor or erythropoietin. Fluoxymesterone, a synthetic androgen, appears to enhance colony growth by increasing the responsiveness of target cells to tropic stimuli. The majority of cells responding to this androgen are in active DNA synthesis. Direct comparison, however, of etiocholanolone-dependent erythroid or granulocytic colony-forming cells demonstrates nonidentity of the target cells. Thus colony-forming units responding to different classes of steroids are in different states of cell cycle and are physically separable. The enhancement of the in vitro response of colony-forming cells to regulating hormones by steroids such as etiocholanolane suggests a mechanism by which such agents may be therapeutically effective in certain cases of marrow failure in man.

A total of 1,921 leukapheresis procedures have been performed on 532 normal and CML donors at six research institutions, for the purpose of supporting granulocytopenic leukemia patients during infectious episodes. The addition of HES alone or in combination with either etiocholanolone or dexamethasone, resulted in a significant increase in the numbers of leukocytes (granulocytes) harvested by continuous and noncontinuous flow centrifugation. Normal donors participating in these programs were monitored prior to and immediately following each procedure by standard laboratory methods which revealed no serious or abnormal changes occurring as a result of the procedure in those undergoing single or multiple donations with these agents. CML donors tolerated the addition of only HES well, as evidenced by the lack of toxic reactions in three donors undergoing 101 to 121 procedures.

Kinins are naturally occurring vasoactive polypeptides thought to be mediators of acute inflammatory responses. Kinins are released from a plasma protein substrate by glass-activated plasma enzymes (kallikreins) or by isolated intact granulocytes. Cortisol in concentrations of 2.5 x 10(-6) to 2.5 x 10(-5)M prevented the release of active kinin from substrate by granulocytes or contact with glass. Deoxycorticosterone, progesterone, and etiocholanolone in comparable concentrations were significantly less effective in preventing kinin release. Plasma obtained from patients receiving prednisone released no kinin after activation by glass and less kinin than control plasma when exposed to granulocytes. Cortisol also partially inhibited the release of kinin by purified urinary kallikrein. Certain adrenocorticosteroids may exert their anti-inflammatory effect by inhibiting the release of plasma kinins. Steroids may act in part by preventing interaction between the activated kallikrein and its substrate.

The effects of a number of steroid compounds on erythropoiesis in normal and polycythemic mice were examined. Of the steroids that stimulated erythropoiesis, the hormone testosterone and certain 5beta-H C(19) and C(21) nonhormonal metabolites were the most effective. Anti-erythropoietin abolished the erythropoiesis-stimulating effects of testosterone but not those exerted by the 5beta-H steroid, 11-ketopregnanolone. Similarly, testosterone but not 11-ketopregnanolone evoked the production of erythropoiesis-stimulating factor in rats. It is concluded that two mechanisms underlie the stimulating actions of steroids on erythropoiesis; one through the production of erythropoietin and the second involving a more direct influence on the blood-forming tissues. The 5beta-H steroid metabolites are postulated to act on erythropoiesis via the latter mechanism.

These studies demonstrate that certain sex steroid metabolites are capable of significantly stimulating the synthesis of both heme and globin in cultured human bone marrow cells. These compounds, which are maximally effective at a concentration of 3 x 10(-8)M, are steroids of the C(19) and C(21) neutral type; share a common 5beta-H (A:B cis) configuration; and are derived from the in vivo biotransformation of testosterone or progesterone, or their intermediates, in man. Since these steroid metabolites have been shown to be capable in other systems of inducing the synthesis of delta-aminolevulinic acid synthetase, the limiting enzyme in the heme biosynthetic pathway, it is hypothesized that their action on human erythroid precursor cells is directed similarly at this enzymatic step leading thereby to increased heme production with consequent stimulation of globin synthesis. This steroid action is independent of erythropoietin, and since these compounds are effective at extremely low concentrations, it is suggested that they may play a physiologic role in the regulation of human erythropoiesis.

The pyrogenic properties of some C-19 and C-21 steroids were examined by in vitro incubation of human blood leukocytes with serum-buffer solutions of the steroids and injection of the 18-hr supernatants into rabbits. In previous studies this method demonstrated release of leukocyte endogenous pyrogen by etiocholanolone. With two exceptions, steroids known to cause fever in man, such as 11beta-OH etiocholanolone and 3alpha-hydroxy-5beta-pregnane-20-one were also pyrogenic in vitro. All steroids tested which are nonpyrogenic in man, such as androsterone, 3beta-OH etiocholanolone, and 3alpha, 17alpha-dihydroxy-5beta-pregnan-20-one were also nonpyrogenic in vitro. Solubility in aqueous solution did not correlate with pyrogenic capacity. Inhibition of pyrogen release from human leukocytes in vitro by hydrocortisone and estradiol was demonstrated. Hydrocortisone-treated leukocytes released less pyrogen than did normal leukocytes when stimulated either by etiocholanolone or by phagocytosis of heat-killed staphylococci. On the other hand, estradiol-treated blood leukocytes and mononuclear cells showed significant suppression of pyrogen release when phagocytosis, but not etiocholanolone, was used as the stimulus. When blood cells were incubated with progesterone, greater than normal amounts of pyrogen were released following phagocytosis, and the inhibiting effect of estradiol could be partially reversed. Neither estradiol nor hydrocortisone appeared to act on rabbit leukocytes. These studies indicate that a variety of naturally-occurring steroids may alter pyrogen release from leukocytes. Alterations in steroid balance in man may influence normal temperature regulation and contribute to clinical fevers.

delta-Aminolevulinic acid synthetase is induced in chick embryo liver culture by the natural steroid, etiocholanolone, and by the foreign chemical, 3,5-dicarbethoxy-1,4-dihydrocollidine at the level of transcription. Alternatively, inducing chemicals such as allylisopropylacetamide and gamma-hexachloro-cyclohexane act primarily at the level of translation. Hemin (K(i) = 5 muM) inhibits the induction at the level of translation. In liver cell culture, the half-life of delta-aminolevulinic acid synthetase is 3 hr, that of mRNA about 5 hr.