In vitro stimulation of chicken pituitary growth hormone and prolactin secretion by chicken hypothalamic extract

Summary The effect of an acid extract of chicken hypothalami on the in vitro secretion of prolactin and growth hormone (GH) by dispersed chicken pituitary cells has been investigated. Both prolactin and GH release were stimulated in a dose related manner in the presence of the hypothalamic extract (HE). Somatostatin had no effect on the basal or HE stimulated release of prolactin although it did inhibit the HE induced release of GH.     

In vitro stimulation of chicken pituitary growth hormone and prolactin secretion by chicken hypothalamic extract.

The effect of an acid extract of chicken hypothalami on the in vitro secretion of prolactin and growth hormone (GH) by dispersed chicken pituitary cells has been investigated. Both prolactin and GH release were stimulated in a dose related manner in the presence of the hypothalamic extract (HE). Somatostatin had no effect on the basal or HE stimulated release of prolactin although it did inhibit the HE induced release of GH.     

Xenopsin stimulates exocrine pancreatic secretion in the dog

Summary The octapeptide xenopsin, previously isolated from amphibian skin, stimulates exocrine pancreatic secretion of bicarbonate and protein in conscious dogs and increases the volume of secretion. This effect is shown in the dose range of 1.25 up to 160 pmoles kg^–1min^–1 The high potency of this peptide is suggestive of a possible physiological role of xenopsin in mammals.This work was supported by the Deutsche Forschungsgemeinschaft Fe 127/4.     

Degeneration secretion from the parotid gland of the dog

Zusammenfassung In der Parotisdrüse von Hunden erscheint eine kurz anhaltende sogenannte Degenerations-sekretion 2–4 Tage nach postganglionär-parasympatischer Denervierung.     

Effect of caerulein infusion on glucagon secretion in the dog

Riassunto L'infusione di ceruleina (2 ng/kg/min) produce nel cane un significativo aumento della concentrazione del glucagone, oltre che della insulina, nella vena pancreatico-duodenale superiore, senza significative modificazioni della glicemia.

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This work was supported by grants from the Consiglio Nazionale delle Ricerche, Rome.     

Activation of sustained sympathetic vasodilatation in dog by spinal cord stimulation

Summary Electrical stimulation in lateral sites of the upper cervical spinal cord evoked vasodilatation after adrenergic blockade. Sympathetic fibres mediating sustained vasodilatation were shown to be separate from adrenergic sympathetic fibres since the adrenergic vasoconstrictor response in the paw evoked by vasomotor stimulation in the medulla was not reversed to vasodilatation after bretylium.Supported by USPHS Grant No. HL 08570 and part of thesis work by Dr.Rolewicz.     

Activation of sustained sympathetic vasodilatation in dog by spinal cord stimulation.

Electrical stimulation in lateral sites of the upper cervical spinal cord evoked vasodilatation after adrenergic blockade. Sympathetic fibres mediating sustained vasodilatation were shown to be separate from adrenergic sympathetic fibres since the adrenergic vasoconstrictor response in the paw evoked by vasomotor stimulation in the medulla was not reversed to vasodilatation after bretylium.     

Action of N-butylnorsympathone on the effects of cardioaccelerator nerve stimulation in the dog]

In Dogs anaesthetized with pentobarbital (30 mg . kg-1), N-butylnorsympathone (20 mg . kg-1 i.v.) reduced the bradycardia induced by stimulating the cardiac nerve (1, 2, 5, 10 Hz). Phentolamine (1 mg . kg-1 i.v.) or yohimbine (0.3 mg . kg-1 i.v.), two potent alpha-adrenoceptor blocking agents known to block presynaptic alpha-adrenoceptor induced a recovery of the effect of cardiac nerve stimulation. Prazosine (0.050 mg . kg-1 i.v.) an alpha-adrenoceptor blocking agent known to be ineffective on presynaptic alpha-adrenoceptors did not induce a recovery. However neither phentolamine or yohimbine were able to prevent the effects of N-butylnorsympathone. Neither haloperidol (0.050 to 2 mg . kg-1 i.v.) or pimozide (0.20 to 1 mg . kg-1 i.v.) induced a recovery or prevented the effects of N-butylnorsympathone. These results suggest that N-butylnorsympathone may stimulate presynaptic receptors which do not resemble classical presynaptic alpha-adrenoceptors or dopamine receptors.     

Regional blood flow antagonism induced by central thermal stimulation in the conscious dog

Zusammenfassung Am wachen Hund wurde bei selektiver thermischer Reizung von Rückenmark und Hypothalamus ein regionaler Durchblutungsantagonismus für das kutane und intestinale Gefässgebiet als thermoregulatorische Antwort nachgewiesen.     

In situ Feulgen reaction with Schiff reagent at different temperatures

Zusammenfassung Mit Feulgenfärbung wurden auf Rattenleber bei Temperaturen von 40 und 60 C die besten Färberesultate erzielt.     

Effect of prednisone on the noradrenaline-induced cell proliferation in the arterial wall

Riassunto Si è studiata la morfologia e la proliferazione cellulare che si instaura nella media dell'aorta e dell'arteria polmonare di conigli sottoposti a trattamento con noradrenalina e con noradrenalina-prednisone facendo uso del metodo autoradiografico dopo somministrazione di³H timidina. Le lesioni e la proliferazione della muscolatura della media che si attuano in seguito a somministrazione di noradrenalina vengono sensibilmente aggravate dal trattamento contemporaneo con prednisone.

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This work was supported by grant No. 71.00179 04-115.1139 of the Consiglio Nazionale delle Ricerche, Roma.     

Interaction of vasoactive intestinal peptide (VIP) with cholinergic stimulation of glucagon secretion

Summary VIP-containing nerve fibers as well as cholinergic nerve fibers have a ubiquitous distribution in the body and both types of nerves have been demonstrated to innervate the pancreatic islets. The present study shows, in the intact, conscious mouse, that VIP and the cholinergic agonist carbachol stimulate glucagon secretion in a dose-dependent manner. Furthermore VIP and carbachol were found to exert potentiating interactions on glucagon secretion. These results suggest the existence of an interactive neural regulation of glucagon secretion, exerted by acetylcholine and VIP.We thank Professor V. Mutt, Karolinska Institutet, Stockholm, for giving us VIP. The skilful technical assistance of Lena K vist and Peter Okmark is gratefully acknowledged. This study was supported by grants from the Swedish Medical Research Council (14P-4289, 14X-4286) and the Medical Faculty, University of Lund, Sweden.     

In situ localization of ACTH receptor-like mRNA in molluscan and human immunocytes

Adrenocorticotropin hormone (ACTH) receptor-like messenger RNA was localized in molluscan hemocytes and human peripheral blood mononuclear cells by in situ hybridization using a digoxigenin-labelled bovine complementary DNA probe. These findings suggest that the ACTH receptor gene has been highly conserved during evolution. Moreover, these data represent further support for a relationship between the immune and neuroendocrine systems in invertebrates, as documented in our previous studies [1]. Received 25 September 1997; received after revision 12 November 1997; accepted 12 November 1997     

Influence of electrical stimulation on the subcellular distribution of dopamine-β-hydroxylase in the dog spleen

Résumé Une stimulation électrique in situ de la rate du chien provoque l'apparition de membranes contenant de la dopamine--hydroxylase. Les membranes sont très probablement le résultat d'une fusion de la membrane axonale et de la membrane vésiculaire, pendant le processus de décharge. Une telle formation de membranes indique que les particules chargées de noradrénaline ne peuvent être utilisées qu'une seule fois.     

Modification of pulsatile pattern of basal insulin secretion in the dog by general anesthesia (Nembutal)

Summary Pulsatile pattern of basal insulin secretion in conscious dog can be modified by the administration of general anesthesia (nembutal): the amplitude of secretory bursts is dramatically reduced. The possibility that a primary control of basal insulin secretion is in the CNS cannot be excluded.     

Complete cold substitution of noradrenaline-induced thermogenesis in the Djungarian hamster,Phodopus sungorus

Summary The thermogenic response to injections of noradrenaline at thermoneutrality was substituted by thermogenesis at low ambient temperatures. This demonstrates that noradrenaline-induced heat production is equivalent to physiologically induced nonshivering thermogenesis during cold exposure.Supported by the Deutsche Forschungsgemeinschaft (He 990).     

Ischemic myocardial injury in cultured heart cells: In situ lysosomal damage

Summary Primary cultures of rat myocardial cells which were subjected to oxygen and glucose deprivation, 2 conditions associated with ischemia, were evaluated for alterations in lysosomal integrity. A photometric technique measured changes in latent acid phosphatase activity and lysosomal membrane permeability.Acknowledgments: The authors thank Dora Fernandez for skillful technical assistance. Research was supported by a grant from the National Heart, Lung, and Blood Institute, HL 18647.     

In vitro secretion of ecdysteroids by Y-organs of the crayfish,Procambarus clarkii

It was demonstrated that excised Y-organs of the crayfish,Procambarus clarkii, synthesize in vitro 3-dehydroecdysone (3-DHE) as the major product, together with small amounts of ecdysone. Both were identified by immunological and spectroscopic methods. The increase of ecdysteroidogenesis in the Y-organs was accompanied by an increase of the major free ecdysteroid, 20-hydroxyecdysone, in the hemolymph. This suggests a physiological role of 3-DHE, the details of which are still to be elucidated.