. The endocrine organs; an introduction to the study of internal secretion . ined. For example, in the case 1 Large doses administered subcutaneously are fatal to rabbits, the symptoms beingsimilar to those caused by adrenalin (see p. 65). Autacoids of Posterior Lobe of Pituitary 97 of the kidney we may be dealing with the action of a single autacoidwhich acts as a chalone upon the blood-vessels of the organ, producinginhibition of their tone, and as a hormone upon the secreting cells, stimu-lating them to increased activity; or two separate autacoids may be con-cerned, one of which affects th
. The endocrine organs; an introduction to the study of internal secretion . ined. For example, in the case 1 Large doses administered subcutaneously are fatal to rabbits, the symptoms beingsimilar to those caused by adrenalin (see p. 65). Autacoids of Posterior Lobe of Pituitary 97 of the kidney we may be dealing with the action of a single autacoidwhich acts as a chalone upon the blood-vessels of the organ, producinginhibition of their tone, and as a hormone upon the secreting cells, stimu-lating them to increased activity; or two separate autacoids may be con-cerned, one of which affects the blood-vessels and the other the cells ofthe organ. The latter view was taken by Herring and myself, but wascombated by Dale, who adduces other examples of the action of drugs inwhich the same active substance produces a double result. If Dales con-tention is correct, we are, so far as the action upon the kidney and itsvessels is concerned, dealing with a single autacoid capable of acting eitherupon both tissues, viz., blood-vessels and secreting cells, or, under certain. A B FIG. 67.—A. Tracing showing the effect of extract of pars nervosa of ox pituitary on isolatedmuscular tissue of rats uterus. (Herring.) The strip was acted upon by the extract duringthe period marked by the signal. B, this tracing was made from the same preparationas that employed to obtain the last tracing. It shows the effect produced by an equivalentamount of extract of pars intermedia. The resulting contraction is smaller and less prolonged. circumstances, upon one only. When its action is produced upon one onlythis may be interpreted to mean that the other is temporarily insensitiveto its action: when, for example, in the action of pituitary upon the kidneythe diuretic action (upon the cells) fails to be produced whilst the vasculareffects are pronounced, or vice versa. But even if this were valid for thekidney, there are strong reasons for the belief that the posterior lobe ofthe pituitary yields
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