Release of gastrointestinal hormones following an oral water load

Summary The ingestion of 2 different water loads (7.5 and 15 ml/kg) by healthy subjects stimulated the release of plasma motilin, gastrin, pancreatic polypeptide and VIP. Atropine was found to block the release of PP but not the other hormones.This work was made possible by generous grants by the Wellcome Trust and Medical Research Council.     

Effect of long acting somatostatin-analogue, SMS 201 995, on gut hormone secretion in normal subjects

SMS 201 995 is a new long acting analogue of somatostatin. We have investigated its effect on basal and meal stimulated secretion of gut hormones and have shown that after a single s.c. injection of 50 micrograms it lowers significantly the basal plasma levels of pancreatic polypeptide, secretin, motilin, pancreatic glucagon and insulin, it also effectively suppresses the postprandial release of pancreatic polypeptide, gastrin, secretin, gastric inhibitory peptide, pancreatic glucagon and insulin. Except for the usual brief discomfort of an injection, no symptoms or untoward effects were observed.     

Effect of long acting somatostatin-analogue,SMS 201995, on gut hormone secretion in normal subjects

Summary SMS 201 995 is a new long acting analogue of somatostatin. We have investigated its effect on basal and meal stimulated secretion of gut hormones and have shown that after a single s. c. injection of 50 g it lowers significantly the basal plasma levels of pancreatic polypeptide, secretin, motilin, pancreatic glucagon and insulin, it also effectively suppresses the postprandial release of pancreatic polypeptide, gastrin, secretin, gastric inhibitory peptide, pancreatic glucagon and insulin. Except for the usual brief discomfort of an injection, no symptoms or untoward effects were observed.     

Studies of total and protein-bound plasma Mg++ in wild and hatchery-reared coho salmon smolts in freshwater and in seawater

Summary Total plasma Mg⁺⁺ and Ca⁺⁺, Mg⁺⁺ in erythrocytes as well as protein-bound plasma Mg⁺⁺ were investigated in wild and hatchery-reared smolts. The proportion of plasma Mg⁺⁺ which was bound to plasma protein did not change significantly during entry into seawater, even though the in vitro addition of exogenous Mg⁺⁺ to the plasma showed that additional binding was possible.     

Endorcine cells producing regulatory peptides

Summary Recent data on the immunologication of regulatory peptides and related propeptide sequences in endocrine cells and tumours of the gastrointestinal tract pancreas, lung, thyroid, pituitary (ACTH and opioids), adrenals and paraganglia have been revised and discussed. Gastrin, xenopsin, cholecystokinin (CCK), somatostatin, motilin, secretin, GIP (gastric inhibitory beenrevised and discussed. Gastrin, xenopsin, cholecystokinin (CCK), somatostatin, motilin, secretin, GIP (gastric inhibitory polypeptide), neurotensin, glicentin/glucagon-37 and PYY (peptide tyrosine tyrosine) are the main products of gastrointestinal endocrine cells; glucagon, CRF (corticotropin releasing factor), somatostatin, PP (pancreatic polypeptide) and GRF (growth hormone releasing factor), in addition to insulin, are produced in pancreatic islet cells; bombesin-related peptidesare the main markers of pulmonary endocrine cells; calcitonin and CGRP (calcitonin gene-related peptide) occur in thyroid and extrathyroid C cells; ACTH and endorphins in anterior and intermediate lobe pituitary cells, -MSH and CLIP (corticotropoin-like intermediate lobe peptide) in intermediate lobe cells; met- and leu-enkephalins and related peptides in adrenal medullary and paraganglionic cells as well as in some gut (enterochromaffin) cells; NPY (neuropeptide Y) in adrenalin-type adrenal medullary cells, etc.. Both tissue-appropriate and tissue-inappropriate regulatory peptides are produced by endocrine tumours, with inappropriate peptides mostly produced by malignant tumours.     

Semen electrolytes in normal and infertile subjects. II. Zinc

Summary Zinc levels in seminal plasma of normal subjects are compared with those of oligospermic, asthenospermic and azoospermic. A linear direct relationship seems to exist between zinc in seminal plasma and motility of spermatozoans. The possible implications of this are discussed.Acknowledgment. Authors are thankful to Mr P. Gopinath, Assistant Professor in Physiology, for valuable criticism on the article and to Mr N.T. Pabani for technical assistance.     

Induction of proteolytic activity in serum by treatment with anionic detergents and organic solvents

Using casein plates as a sensitive assay for proteolytic activity, it was observed that sodium-dodecyl sulfate (SDS) and other anionic detergents induce caseinolysis when mixed with sera and plasma. Caseinolysis was dependent on the presence of plasminogen in the fluids and could be blocked by inhibitors of serine proteases and antibody to plasminogen. Similarly, organic solvents such as isopropanol induced caseinolysis after mixing with plasma, but not normal serum. Isopropanol dissociated complexes of alpha 1-antitrypsin or alpha 2-macroglobulin with trypsin preformed in vitro. As both SDS and organic solvents are widely used in biochemical investigations of biological fluids, attention should be paid to the possible induction of proteolysis.     

A generalized homology correlation for various hormones and proteins

Résumé La calcitonine, la cholécystokinine, la motilin, la pancreozymine, le peptide inhibiteur gastrique, le peptide vasoactif, la gastrine, le glucagon, et la secretine sont comparables par leur composition en amino acides a l'hormone de croissance, à l'hormone luteinigène, la gonadotropine, au facteur de croissance nerveux, à l'hormone parathyroidienne, au lactogène du placenta, à la proinsuline, à la rénine et à la thyrotropine. Ces peptides proviennent probablement d'un génotype dont l'origine se trouve dans le système digestif.     

Interaction of lipid transfer protein with plasma lipoproteins and cell membranes

Summary The hydrophobic lipid components of lipoproteins, cholesteryl ester and triglyceride, are transferred between all lipoproteins by a specific plasma glycoprotein, termed lipid transfer protein (LTP). LTP facilitates lipid transfer by an exchange process in which cholesteryl ester and triglyceride compete for transfer. Thus, LTP promotes remodeling of the lipoprotein structure, and plays an important role in the intravascular metabolism of these particles and in the lipoprotein-dependent pathways of cholesterol clearance from cells. The properties of LTP, its mechanisms of action, its roles in lipoprotein metabolism, and its modes of regulation are reviewed along with recent data that suggest a possible role for this protein in directly modifying cellular lipid composition.     

Evidence for existence of pores in intramembranous particles revealed by freeze fracturing]

In freeze-fracture replicas of membranes (plasma and intracellular) in a variety of animal cells, it is possible to detect the presence of intramembrane particles containing an electron-dense spot. The spot is interpreted as an accumulation of platinum into a cavity; the cavity could in turn correspond to a hydrophilic pore in the particle.     

Wechselwirkungen zwischen fördernden und hemmenden Substanzen der Blutgerinnung

Summary The reactions of the lipoid activator and different thrombokinases, both alone and together with sphingosine-containing plasma, are described. In connection with the results reported, the possible significance of the physiological substances for the physiopathology of blood clotting, and the generation of plasma thrombokinase, is discussed.      

Cyclosporin A enhances streptozocin-induced diabetes in CD-1 mice

Cyclosporin A (CYA), when administered to CD-1 mice treated with a subdiabetogenic dose of Streptozocin (STZ), exacerbated the STZ-induced insulitis and elevated the plasma glucose levels, parallel to a reduction of the insulin content of the pancreas. The possible mechanisms of CYA-mediated aggravation of STZ-induced diabetes are discussed.     

Effect of 2-mercaptopropionylglycine (MPG) on thyroid function in sub-lethally irradiated mice

Summary External irradiation resulted in an increase in thyroid¹³¹I uptake and plasma PB¹³¹I conversion ratio, whereas pretreatment with MPG reduced both the values significantly. Metabolic inhibition is suggested as a possible mechanism of action by the drug.Acknowledgment. The financial support from the CSIR, India, in the form of a research grant is gratefully acknowledged. Our thanks are also due to Prof. P. Navalkha, Radiotherapy Unit, SMS Hospital, Jaipur, for providing irradiation facilities.     

Currents through ionic channels in multicellular cardiac tissue and single heart cells

Ionic channels are elementary excitable elements in the cell membranes of heart and other tissues. They produce and transduce electrical signals. After decades of trouble with quantitative interpretation of voltage-clamp data from multicellular heart tissue, due to its morphological complexness and methodological limitations, cardiac electrophysiologists have developed new techniques for better control of membrane potential and of the ionic and metabolic environment on both sides of the plasma membrane, by the use of single heart cells. Direct recordings of the behavior of single ionic channels have become possible by using the patch-clamp technique, which was developed simultaneously. Biochemists have made excellent progress in purifying and characterizing ionic channel proteins, and there has been initial success in reconstituting some partially purified channels into lipid bilayers, where their function can be studied.     

慢性心力衰竭失代偿患者血浆β-内啡肽与脑钠肽变化的意义

目的探讨慢性心力衰竭（CHF）患者血浆β-内啡肽（β-EP）在诊断和预后中的意义。材料和方法CHF患者71例,按NY-HA心功能分级分为3组（Ⅱ一Ⅳ）。应用放射免疫法（RIA）测患者血浆β-EP浓度,采用床旁Triager BNP测定仪测定同期血浆脑钠肽（BNP）量。结果CHF各组血浆β-EP和BNP含量与对照组相比显著性升高,并随心功能分级的增加呈上升趋势（P〈0．01）。CHF组血浆β-EP与BNP呈显著性线性正相关（P〈0．01）;血浆β-EP和BNP水平与EF值及EF呈显著性线性负相关（P〈0．01）。血浆中β-内啡肽含量越高则半年内心血管事件发生率越高（P〈0．01）。结论血浆β-内啡肽和BNP的水平是诊断CHF的重要实验室指标,并可用于心功能及预后的评估。     

Endocrine cells producing regulatory peptides

Recent data on the immunolocalization of regulatory peptides and related propeptide sequences in endocrine cells and tumors of the gastrointestinal tract, pancreas, lung, thyroid, pituitary (ACTH and opioids), adrenals and paraganglia have been revised and discussed. Gastrin, xenopsin, cholecystokinin (CCK), somatostatin, motilin, secretin, GIP (gastric inhibitory polypeptide), neurotensin, glicentin/glucagon-37 and PYY (peptide tyrosine tyrosine) are the main products of gastrointestinal endocrine cells; glucagon, CRF (corticotropin releasing factor), somatostatin, PP (pancreatic polypeptide) and GRF (growth hormone releasing factor), in addition to insulin, are produced in pancreatic islet cells; bombesin-related peptides are the main markers of pulmonary endocrine cells; calcitonin and CGRP (calcitonin gene-related peptide) occur in thyroid and extrathyroid C cells; ACTH and endorphins in anterior and intermediate lobe pituitary cells, alpha-MSH and CLIP (corticotropin-like intermediate lobe peptide) in intermediate lobe cells; met- and leu-enkephalins and related peptides in adrenal medullary and paraganglionic cells as well as in some gut (enterochromaffin) cells; NPY (neuropeptide Y) in adrenaline-type adrenal medullary cells, etc.. Both tissue-appropriate and tissue-inappropriate regulatory peptides are produced by endocrine tumours, with inappropriate peptides mostly produced by malignant tumours.     

Internalization of polypeptide hormones and receptor recycling

Conclusion The insulin receptor is an integral protein of the plasma membrane of the cell. It is composed of two subunits: an subunit, which binds the hormone, and a subunit which is a tyrosine specific protein kinase capable of undergoing autophosphorylation. These independent subunits are synthesized by way of a higher molecular weight single chain precursor and thus are the product of a single gene^{29, 49, 85} localized to chromosome 19^{29, 91}. Assuming that the insulin receptor is synthesized in the same fashion as other integral membrane glycoproteins, then the nucleus, the rough endoplasmic reticulum, and the Golgi apparatus are involved in its biosynthesis. Further, there must be some form of transport of the mature receptor subunits to the plasma membrane where they are inserted.By contrast, the endocytotic route involves coated pits, coated vesicles, large clear vesicles or endosomes, multivesicular bodies and other lysosomal forms. In addition, it is possible that some other as yet unidentified organelle is involved in recycling (fig. 8). At the present time, with respect to the insulin receptor, the biosynthetic pathway and the endocytotic pathway appear to be separate. Further, it does not appear that either pathway, i. e. synthesis or endocytosis, exerts a regulatory function over the other.     

Membrane traffic in the secretory pathway

It is generally thought that microtubule-associated motors insure long-range movements of the secretory vesicles from the center of the cell to its periphery, while myosins insure short-range movements at the cell periphery. However, several of the myosins that have been reported during the last decade to be involved in the exocytic pathway are not processive, meaning that they do not have the ability to move cargos along actin polymers. We will review here the possible mechanisms by which these myosins could contribute to the traffic of secretory proteins from the Golgi complex to the plasma membrane.     

Plasma, testicular, and adrenal cortex levels of androgens in the perinatal period and determination of neonatal hypertestosteronemia in guinea pigs]

The perinatal period is characterized in the male faetus and new-born Guinea-Pig by a prenatal increase in testis testosterone and by a neonatal peak in plasma testosterone. This transient rise in plasma testosterone is testis dependent and light dependent at birth.     

Pineal function in the sheep: evidence for a possible mechanism mediating seasonal reproductive activity

Summary The 24-h profiles of plasma melatonin in the intact ewe in natural light indicate that a bimodal pattern of secretion is frequently present in oestrus, whereas a single dark-phase peak is characteristic of anoestrus. Based on these findings, a mechanism for the possible pineal-mediated control of seasonal breeding is proposed.This work was supported by the Medical Research Council and the Agricultural Research Council of Great Britain. Preliminary results from this study were reported in the proceedings of the 1st meeting of the European Pineal Study Group; J. Arendt, Prog. Brain Res.52, 249 (1979).We are grateful for the excellent technical assistance of A. Marston and J. Bradtke.