A. J. de Bold

Isolation and nucleotide sequence of a cloned cardionatrin cDNA

A cloned cDNA which codes for the C-terminal 62 residues of the precursor molecule for the atrial natriuretic factor, cardionatrin, has been isolated and sequenced. The nucleotide sequence confirms the amino acid sequence of cardionatrin 1-28 previously determined, and positions this peptide at the C-terminal end of the precursor just two residues away from the termination codon.

Plasma atrial natriuretic factor and urinary excretion of a ouabain displacing factor and dopamine in normotensive pregnant women before and after delivery.

Estimation of urinary excretion of a ouabain displacing factor and dopamine was carried out immediately before delivery, and 7 days and 70 to 90 days after delivery in 12 normotensive pregnant women. Simultaneous estimation of plasma 99-126 atrial natriuretic factor, plasma renin activity, and plasma aldosterone were also undertaken. The data were compared with those obtained in a group of nonpregnant normotensive women (n = 14) and a group of pregnant normotensive women in the early phase of the third trimester (n = 14). Urinary ouabain displacing factor and dopamine levels were significantly higher in the early phase of the third trimester, as compared with nonpregnant women. But immediately before delivery, ouabain displacing factor excretion had fallen below nonpregnant values and dopamine excretion had dropped to control values. Both remained low after delivery. Plasma atrial natriuretic factor was higher in pregnant women, as compared with nonpregnant controls and remained high just before delivery and 7 and 70 to 90 days after delivery. Plasma renin activity and plasma aldosterone levels were higher during pregnancy and had fallen to nonpregnant values 7 days post partum. This drop in plasma renin activity and aldosterone by 7 days post partum, in contrast with the unchanged high values of atrial natriuretic factor, may contribute to negative sodium balance after delivery. It is concluded that there is considerable discrepancy in natriuretic and antinatriuretic factors before and after delivery.

Intracellular pancreatic B cell serotonin and the dynamics of insulin release

SummaryThe role of intracellular pancreatic B cell serotonin in the dynamics of insulin release was investigated in an in situ perfused rat pancreas preparation. Animals were pretreated with 5-hydroxytryptophan (5-HTP) to increase the intracellular levels of serotonin (5-HT) as shown by fluorescence histochemistry. Despite a clear induction of intracellular 5-HT fluorescence in pancreatic islets neither the pattern nor the total amount of insulin released were significantly modified after perfusion with either glucose or tolbutamide. However, the L-amino acid decarboxylase inhibitor, RO 4-4602, significantly decreased both phases of glucose-mediated insulin release in normal animals as well as in those receiving 5-HTP.

L'hypertension artérielle peut-elle être expliquée par une anomalie de sécrétion du facteur atrial natriurétique et de l'endothéline ?

Plasma ANF and endothelin levels were measured in normotensive and hypertensive pregnant women and in non-pregnant controls. If ANF levels were normal in pregnant women the results concerning endothelin may account for the prevention in hypertensive pregnancy of the vasodilatation occuring in normal pregnancy.

Plasma Cardionatrin and Volume and the Renin Angiotensin Aldosterone System in Normotensiye and Hypertensive Pregnancy

Cardionatrin is the 28 aminoacid atrial natriuretic peptide which is released into the circulation from its storage granules when the atria are stretched, (1,2). This peptide has both remarkable natriuretic and vasodilating properties and suppresses the renin angiotensin aldosterone system. It may therefore be Implicated in the pathogenesis of hypertension. So far it has been investigated only In essential hypertension and shown to be increased (3). It has not yet been evaluated in pregnancy induced hypertension (PIH) or preeclampsia. Therefore we measured plasma concentrations of cardionatrin in pregnant women with normal blood pressure as well as in women with PIH and preeclampsia during pregnancy and after delivery, simultaneouly with their plasma volume, blood uric acid, plasma renin activity (PRA) and plasma concentrations of aldosterone(PA).

Demonstration of Stellate Cells of the Pars Intermedia of the Pituitary Gland Using a New Silver Impregnation Technique

The pars intermedia of the pituitary gland in the rat and other species contains, in addition to secretory cells, stellate cells first characterized by using electron microscopy. The distribution and relationships of these cells is difficult to assess at the ultrastructural level. We have developed an ammoniacal silver nitrate method for stellate cells of the pars intermedia. Staining is carried out in 15 micron sections of buffered formalin fixed, paraffin embedded pituitaries. This method shows that in the rat pars intermedia, stellate cells showing numerous cytoplasmic projections are abundant in, and evenly distributed throughout, pars intermedia lobules.

Pyruvate kinase activity in the lymphocytes of malnourished, anergic patients

Abstract Intralymphocytic pyruvate kinase (PK) has been reported to have decreased activity in protein calorie malnutrition. We studied the activity of this enzyme in the lymphocytes of normal, nonhospitalized individuals (Group 1: n = 14) and malnourished, anergic patients on the surgical ward (Group 2: n = 17). The mean activity in Group 2 (0.12 ± 0.02 U/10 7 cells) was significantly decreased ( P 7 cells). Five of the patients in Group 2 were studied following return to normal skin reactivity and prior to discharge from hospital; their mean activity had returned to the normal range (0.32 ± 0.08; P n = 7) and malnourished, anergic patients (Group 4: n = 5) showed a significant reduction in V max of Group 3 (0.51 ± 0.02 U/10 7 cells) as compared to Group 4 (0.35 ± 0.03 U/10 7 cells), P K m in Group 4 showed a significant increase (1.59 ± 0.26 m M ) as compared to Group 3 (0.71 ± 0.09), P V max and K m in the malnourished, anergic patient and suggest that examination of this enzyme may help to define the lymphocytes of malnourished, anergic patients.