H1-histamine receptors may mediate the contractile response of guinea-pig ileum to 'histamine-free' splenic extracts.

A water-soluble splenic factor, which produces a contractile response of the guinea-pig ileum, that is resistant to cholinoceptor and adrenoceptor antagonists is described. The ileal contractions elicited by the splenic extract showed some significant differences from those elicited by 5-hydroxytryptamine. The responses to splenic extract were not affected by the D-tryptamine-receptor antagonist, methysergide. The effect of the splenic extract on the guinea-pig ileum was similar to that of histamine. The H1-histamine antagonists, (+)-chloropheniramine and diphenhydramine, caused a parallel shift to the right of the splenic extract dose-response curve without suppression of the maximum response. A pA2 value of 8.97 +/- 0.03 for (+)-chloropheniramine and 7.55 +/- 0.1 for diphenhydramine was calculated. Significant histamine levels, as determined by fluorometric methods, could not be detected in the splenic extract. Likewise, the splenic factor did not release histamine from the intestinal preparation. These results support the view that: (i) the splenic factor acts through H1-histamine receptors; (ii) it is not histamine; (iii) it does not have any histamine releasing effect on the ileal smooth muscle.

[Incorporation of 1-C14 palmitic acid into liver lipids of rats in different hormanal states]. / Incorporación de 1-C14 ácido palmítico a lípidos hepáticos de rata en diferentes estados hormonales

Adrenalectomy and/or cortisol-induced variations in the in vivo and in vitro incorporation of 14C-palmitic acid 1 into the different fractions of rat liver lipids were studied. The different fatty acids incorporations follow analogous patterns in every hormonal state in vitro. Incorporation rate is faster in normal animals, but adrenalectomy or the administration of cortisol produces a marded delay. Cortisol does not modify the anomalism observed in the adrenoprival state. In vivo, the incorporation of palmitic acid into the different liver lipids--for the same hormonal state--does not follow the same pattern.

[Effects of adrenalectomy and cortisol administration on the concentration of free fatty acids, triglycerides and total lipids on the liver of rats]. / Efectos de la adrenalectomía y de la administración de cortisol sobre las concentraciones de ácidos grasos libres, triglicéridos y lípidos totales en hígado de rata

The hepatic concentration of triglycerides, free fatty acids and total lipids was determined in four groups of rats: normals, adrenectomized and normal and adrenectomized previously treated with cortisol, 30 mg. In chronic adrenectomized state, total lipids and hepatic triglycerides are diminished, particularly the triglycerides. Adrenectomy does not appear to have significative effect on the free fatty acids. The administration of cortisol does not change those observations and, when given to normal animals, decreases the hepatic concentrations of free fatty acids, triglycerides and total lipids.

[Effect of adrenalectomy and the administration of cortisol on plasma and liver cholesterol free and esterified in rats]. / Efectos de la adrenalectomía y de la administración de cortisol sobre el colesterol (libre y esterificado) en plasma e hígado de rata

The effect of cortisol on the levels of free and sterified cholesterol in the livers of normal and adrenectomized rats has been studied. The results indicate that cortisol enhances those lipids in plasma and decreases their level in the liver.