Different effects of aging on the opioid mechanisms controlling gonadotropin and cortisol secretion in man

The present study was undertaken in order to assess the influence of aging on the endogenous opioid control of gonadotropin and adrenocorticotropin/cortisol secretion in man. For this purpose, the capability of the opioid antagonist naloxone to increase circulating levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH) and cortisol was tested in male subjects of different ages. Thirty normal men were randomly chosen and divided into 3 groups by age: group I = 22-40 years (n = 10); group II = 41-59 years (n = 10); group III = 62-80 years (n = 10). Since the men of group III showed higher basal serum gonadotropin concentrations than the subjects of group I and group II, we selected from a large population a fourth group of elderly men with normal basal LH and FSH levels: group IV = 61-82 years (n = 7). All subjects were tested for 120 min during the intravenous administration of naloxone (4 mg given in an intravenous bolus at time 0, plus 10 mg infused for 2 h). Control tests with normal saline instead of naloxone were performed in all groups. All subjects had similar blood testosterone and cortisol levels, whereas LH and FSH concentrations were significantly higher in group III than in groups I, II and IV. Naloxone increased plasma cortisol concentrations by 50% in all groups. The cortisol secretory response followed a similar pattern regardless of age.(ABSTRACT TRUNCATED AT 250 WORDS)     

On-line high-performance liquid chromatography-fluorescence detection-electrospray ionization-mass spectrometry profiling of human milk oligosaccharides derivatized with 2-aminoacridone

A high-resolution normal-phase high-performance liquid chromatography-fluorescence detection-electrospray ionization-mass spectrometry separation and structural characterization of the main oligosaccharides along with lactose from human milk samples is described. A total of 22 commercially available oligosaccharides were fluorotagged with 2-aminoacridone and separated on an amide column and identified on the basis of their retention times and mass spectra. Derivatized species having mass lower than approximately 800 to 900 exhibited mainly [M-H](-1) anions, oligomers with mass up to approximately 1000 to 1100 were represented by both [M-H](-1) and [M-2H](-2) anions, and oligomers greater than approximately 1200 to 1300 were characterized by a charge state of -3. Furthermore, the retention times were directly related to the glycans' molecular mass. Human milk samples from the four groups of donors (Se±/Le±) were analyzed for their composition and amount of free oligosaccharides after rapid and simple prepurification and derivatization steps also in the presence of lactose in high content. This analytical approach enabled us to perform the determination of species not detected by traditional techniques, such as sialic acid, as well as of species present in low content easily mistaken with other peaks. Finally, labeled human milk oligosaccharides were analyzed without any interference from excess fluorophore or interference from proteins, peptides, salts, and other impurities normally present in this complex biological fluid.     

Inhibition of chemotactic factor-induced neutrophil responsiveness by arachidonic acid

Arachidonic acid when added simultaneously with the chemotactic peptide formyl-methionyl-leucyl-phenylalanine (f-Met-Leu-Phe) inhibits the ability of the latter to initiate several but not all of its effects on rabbit peritoneal neutrophils. Stimulated neutrophil aggregation, calcium uptake, and increases in the steady state level of exchangeable calcium are all inhibited by 1-10 microM arachidonic acid. The binding of f-Met-Leu-Phe and the parameters of intracellular calcium redistribution (calcium efflux and changes in the steady state level of exchangeable calcium in the absence of extracellular calcium) and of stimulated sodium uptake are, on the other hand, unaffected by the same concentrations of arachidonic acid. Arachidonic acid, the saturated analog of arachidonic acid, was found not to inhibit f-Met-Leu-Phe-stimulated aggregation and calcium uptake. Arachidonic acid, therefore, in addition to its well-described agonist properties, also possesses antagonist activities toward rabbit neutrophils. These results add a new level of complexity to the study of the role of arachidonic acid in cell activation.