5 alpha-Dihydro-11-deoxycorticosterone: effect on blood pressure in the rat

The bioactivity of 5 alpha-reduced sex steroids such as 5 alpha-dihydrotestosterone has increased interest in an analogous role for 5 alpha-reduced mineralocorticoids in hypertensive syndromes. In view of its relatively high mineralocorticoid receptor affinity despite relatively low electrolyte-altering effects, 5-alpha-dihydro-11-deoxycorticosterone, or 5 alpha DHDOC (2) was compared to 11-deoxycorticosterone acetate (DOCA) for blood pressure-altering ability by continuous subcutaneous infusion into uninephrectomized saline-drinking Sprague-Dawley male rats, at doses selected on the basis of relative mineralocorticoid receptor affinity. After three weeks of treatment, DOCA significantly raised blood pressure, body weight, heart and kidney weight, and produced a discernible increase in fluid intake; 5 alpha DHDOC failed to affect any of these parameters commonly influenced by mineralocorticoids. We conclude that 1) the ability of 5 alpha DHDOC to affect blood pressure was not predicted by its relatively high affinity for the mineralocorticoid receptor, and 2) these data do not support a role for 5 alpha DHDOC in mineralocorticoid hypertension, although differences in protein binding and clearance could affect its blood pressure-altering activity.

Effect of sulfinpyrazone on platelet survival time in patients with transient cerebral ischemic attacks

Platelet suppressant drugs have been suggested as beneficial for patients with transient cerebral ischemic attacks and these drugs have been shown to lengthen shortened platelet survival time. In the present study platelet survival time (autologous labeling with 51Chromium) was measured in 25 patients with transient cerebral ischemia involving a carotid distribution. Platelet survival was shortened in all patients (2.5 +/- 0.10 days; AVE t 1/2 +/- SEM; Normal 3.7 +/- 0.04 days P less than 0.001). Sulfinpyrazone increased platelet survival in 9 of 19 (47%) of patients (2.4 +/- 0.10 to 2.8 +/- 0.16 days; P less than 0.01). Of the 19 treated with sulfinpyrazone, 10 had a marked reduction in the frequency of transient ischemic episodes and an increased in platelet survival (2.6 +/- 0.16 to 3.1 +/- 0.22 days; P less than 0.01) was observed in all patients. Three patients had no benefit from sulfinpyrazone and alteration of platelet survival did not occur. Results suggest that platelet survival is shortened in patients with transient cerebral ischemia, that sulfinpyrazone increases platelet curvival and may decrease the frequency of ischemic episodes, and that there may be a relationship between clinical benefit and alteration of platelet survival time.

Extensive primary lymphoma of the gastrointestinal tract

A case of extensive primary lymphocytic lymphoma (lymphosarcoma) of the gastrointestinal tract is reported. At the time of presentation the patient had diffuse involvement of the gastrointestinal tract from the stomach to the ano-rectal junction. Malabsorption was present. Pre-treatment immunologic studies showed elevated serum IgA and IgG, but impaired humoral and cellular immunity. Death occurred 13 months after diagnosis.

Studies on Effects of Certain Quinones: II. Photosynthetic Incorporation of CO(2) by Chlorella

The effects of various quinone herbicides and fungicides on the photosynthetic (14)CO(2) fixation and the incorporation of (14)C among the products of photosynthesis in Chlorella pyrenoidosa was investigated. Addition of 30 mum 2,3-dichloro-1,4-naphthoquinone (dichlone), 2-amino-3-chloro-1,4-naphthoquinone (06K-quinone), or 2,3,5,6-tetrachloro-1,4-benzoquinone (chloranil) inhibited CO(2) fixation, whereas 1,4-benzoquinone had no effect. Treatment with 3 mum or higher concentrations of dichlone, 06K-quinone or 1,4-benzoquinone also produced marked changes in the pattern of (14)C distribution. A noticeable effect was an increase in the proportion of (14)C in sucrose and glycine accompanied by a reduction in (14)C lipids and glutamic acid. These changes appear to occur as a result of shifts in the flow of carbon along various biosynthetic pathways of photosynthetic CO(2) fixation. It is suggested that inactivation of coenzyme A and shortage of reduced triphosphopyridine nucleotide in the quinone-treated cells inhibited the synthesis of lipids and glutamic acid, thereby diverting more carbon into sucrose and glycine.

Purification from rat liver of an enzyme that catalyses the sulphurylation of phenols

1. An enzyme (EC 2.8.2.1) that catalyses the transfer of sulphate from adenosine 3'-phosphate 5'-sulphatophosphate to phenols was purified approx. 2000-fold from male rat livers. 2. The purified preparation did not catalyse the sulphurylation of dehydroepiandrosterone, butan-1-ol, l-tyrosine methyl ester, 1-naphthylamine or serotonin. 3. At pH8.0 and 37 degrees C the K(m) values of the enzyme for p-nitrophenol and adenosine 3'-phosphate 5'-sulphatophosphate are 51 and 14mum respectively. The K(m) value for either substrate is independent of the concentration of the other. 4. The sulphurylation of phenol is inhibited by thiol compounds and glutathione at a concentration of 3mm caused an approx. 50% decrease in enzyme activity. 5. The K(m) of the enzyme for adenosine 3'-phosphate 5'-sulphatophosphate is unaffected by the presence of added glutathione but at a concentration of 5mm-glutathione the K(m) of the enzyme for its phenolic substrate is decreased.