Carboxy-terminal amidation of biologically active peptides, an important characteristic of more than half of these substances, occurs during the maturation process of peptide precursors. It is catalyzed by peptidylglycine alpha-amidating monooxygenase (PAM), an enzyme that is copper-dependent. We show here that alterations of copper stores in cultured cells from different origins (pancreas and hypothalamus) affect the immunoreactivity of thyrotropin-releasing hormone (TRH) and corticotropin-releasing factor (CRF) (two alpha-amidated peptides). This suggests that copper can affect neuropeptide biosynthesis and may play a role in the endocrine or central nervous system function.

Amino Acid Sequence↗

PubMedDate not supplied

Regulation of TRH release by the cultured neonate rat pancreas.

The TRH secretory responsiveness of the pancreatic islet cell clusters from newborn rat in organ culture was studied. Basal TRH secretion was stable over a 9-day period. The response to various secretagogues was tested on day 4. TRH secretion was stimulated by high potassium-induced depolarization and also through both cAMP and protein kinase-C dependent pathways. Like insulin, TRH release was stimulated by glucose and arginine and inhibited by somatostatin. These data suggest the existence of a common mechanism for TRH and insulin secretion by the pancreatic beta-cells.

8-Bromo Cyclic Adenosine Monophosphate↗

PubMedDate not supplied

[Study of the fungal content of expired air in humans].

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Air Microbiology↗

PubMedDate not supplied

Clinical and hemodynamic effects of dobutamine in acute myocardial infarction with left heart failure.

We studied the clinical and hemodynamic effects of dobutamine infused for 24 hr into 10 patients with acute myocardial infarction (less than 4 days) complicated by left heart failure (pulmonary wedge pressure greater than 15 mm Hg, cardiac index less than 3.0 liters/min/m2). We measured pulmonary arterial pressures, pulmonary wedge pressure, right atrial pressure, and intravascular systemic blood pressures. The thermodilution method was used for determinations of cardiac output, and the electrocardiogram was followed with a computerized arrhythmia monitoring system. After 1 and 3 hr of infusion with the optimal dose (averaging 8 micron/kg/min), there was a very significant increase of cardiac index (29%) and a decrease of pulmonary wedge pressure (37%) with a moderate increase of heart rate (20%) an without significant changes in blood pressure. After 24 hr of dobutamine infusion, much of the improvement in left ventricular function was lost. This may be attributed either to a decrease of drug action or to an unfavorable evolution of the clinical status. We conclude that infusion of dobutamine is an effective, potent, and well-tolerated short-term procedure in the management of left heart failure during the acute stage of myocardial infarction.

Adult↗

PubMedDate not supplied