The sterols of Cucurbita moschata ("calabacita") seed oil.

From the sterol fraction of seed oil from commercial Cucurbita moschata Dutch ("calabacita") delta 5 and delta 7 sterols having saturated and unsaturated side chain were isolated by chromatographic procedures and characterized by spectroscopic (1H and 13C-nuclear magnetic resonance, mass spectrometry) methods. The main components were identified as 24S-ethyl 5 alpha-cholesta-7,22E-dien-3 beta-ol (alpha-spinasterol); 24S-ethyl 5 alpha-cholesta-7,22E,25-trien-3 beta-ol (25-dehydrochondrillasterol); 24S-ethyl 5 alpha-cholesta-7,25-dien-3 beta-ol; 24R-ethyl-cholesta-7-en-3 beta-ol (delta 7-stigmastenol) and 24-ethyl-cholesta-7, 24(28)-dien-3 beta-ol (delta 7,24(28)-stigmastadienol).

Effects of juvenile hormone on mammalian steroidogenesis.

The effects of juvenile hormone-III (JH-III) and the JH analogue 2-(4-phenoxyphenoxy)-ethoxyte-trahydropiran on testicular steroidogenesis were studied. By using cultured MA-10 Leydig tumor cells as a model, these compounds were found to be potent inhibitors of LH/hCG steroidogenic action in a dose-dependent manner. Scatchard plot analysis of the binding data indicated that the JH analogue did not significantly alter the affinity nor the number of hCG binding sites, as well as GTP binding to plasma membranes. JH analogue inhibited the stimulatory action of both cholera toxin and forskolin on cAMP production and the concomitant steroidogenic response. JH analogue inhibited (Bu)2cAMP-stimulated progesterone synthesis, indicating that a process downstream to the adenylyl cyclase in the steroidogenic pathway is also affected.

Síntesis, controles químicos y radioquímicos del "mebrofenin-Tc-99m": estudios radiofarmacológicos y usos en seres humanos / Synthesis, chemical and radiochemical cotrols of mebrofenin-Tc-99m: radiopharmacological studies and uses in humans

En este trabajo se presenta el estudio químico radiofarmacológico y el uso en seres humanos realizado con el "mebrofeini-Tc-99m". La finalidad del trabajo fue determinar el uso potencial de este radiofármaco en seres humanos portadores de distintas entidades clínico patológicas. Para esto, se sintetizó el producto mejorando el rendimiento de reacción, mediante una modificación en la segunda etapa del camino de síntesis, lo que condujo a elevarlo del 70 al 90%. Se determinó la cinética plasmática mediante la circulación extracorpórea realizada en ratas wistar, mientras que la hepática y renal se llevó a cabo en ratones endocriados. Todos los resultados fueron analizados mediante un procesador, obteniéndose las vidas medias plasmáticas y los máximos tiempos de captación

Cyclic biospecific affinity chromatographic method for the purification of the sex steroid binding protein (SBP): application to the purification of SBP from toad.

A novel biospecific affinity chromatographic procedure was developed for the purification of the sex steroid binding protein from Bufo arenarum. A charcoal column connected in series to the affinity column allows the removal of any ligand non-covalently bound to the matrix or released during its storage, thus avoiding the need for exhaustive and prolonged washing procedures. In addition, it is not necessary to remove the endogenous ligand from the starting material and the binding to the affinity column can be monitored to determine the time required to achieve the maximum yield. The advantages are the charcoal adsorption of the ligand "washed" from the affinity column by the protein to be purified and the amplification provided by the cyclic use of the system. The procedure improves the yield from less than 1% (by conventional procedures) to more than 50%. With minor modifications this procedure can be useful for the purification of binding proteins and receptors.

Analysis of urinary steroid profiles of women with Cushing's syndrome by computerised gas chromatography-mass spectrometry.

Urinary steroidal profiles were studied in five women with Cushing's syndrome and in two normal women that were chosen as controls, by means of gas chromatography and gas chromatography-mass spectrometry. Four patients presented ACTH-dependent adrenal hyperplasia and the last patient had an adrenocortical carcinoma. Steroids were analyzed in urinary extracts, as their respective trimethylsilyloximes and/or trimethylsilylderivatives. Qualitative and quantitative data about 36 urinary steroids were obtained. Three pituitary patients showed a well defined picture of "5-ene pathway" in adrenal function. The fourth patient depicted some primary deficiencies of corticosteroid biosynthesis that overshadowed most biochemical expressions of Cushing's disease. The patient with adrenal carcinoma developed a steroidal pattern resembling autonomous functioning of adrenal cortex inner zones, showing both "5-ene pathway" and "4-ene pathway" increase. This patient also had an unexpected excretion of a major metabolite of 18-hydroxycorticosterone, that did not correlate with parameters of aldosterone production. Tetrahydro-6-hydroxy-cortisol was determined in urine of two patients and original data about urinary cortoic acids in Cushing's syndrome are given. Peripheral reductive metabolism played the most important role in almost all patients. In turn, some oxidative metabolic pathways for cortisol were not specifically favoured in the cases of Cushing's disease here reported.