Search results for "Secretion"
showing 10 items of 764 documents
The nasus gland: A new gland in soldiers of Angularitermes (Termitidae, Nasutitermitinae)
2015
Termites have developed many exocrine glands, generally dedicated to defence or communication. Although a few of these glands occur in all termite species, or represent synapomorphies of larger clades, others are morphological innovations of a single species, or a few related species. Here, we describe the nasus gland, a new gland occurring at the base of the nasus of Angularitermes soldiers. The nasus gland is composed of class 1, 2, and 3 secretory cells, a rare combination that is only shared by the sternal and tergal glands of some termites and cockroaches. The ultrastructural observations suggest that the secretion is produced by class 2 and 3 secretory cells, and released mostly by cl…
PCOS Phenotypes: Impact on Fertility
2018
Polycystic ovary syndrome (PCOS) is characterised by an extreme heterogeneity and at least four main phenotypes may be distinguished. In referred population, anovulatory hyperandrogenic phenotype (classic PCOS or phenotypes A and B) is by far the most common phenotype and presents the most severe endocrine and metabolic alterations. Ovulatory PCOS and normoandrogenic phenotype represent a mild form of PCOS that is more common in general population and/or (normoandrogenic) in some particular ethnic group. During their life, because of changes in lifestyle or because of spontaneous changes in ovarian and adrenal androgen secretion that occur during late reproductive age, patients may move fro…
The Role of the α Cell in the Pathogenesis of Diabetes: A World beyond the Mirror
2021
Type 2 Diabetes Mellitus (T2DM) is one of the most prevalent chronic metabolic disorders, and insulin has been placed at the epicentre of its pathophysiological basis. However, the involvement of impaired alpha (α) cell function has been recognized as playing an essential role in several diseases, since hyperglucagonemia has been evidenced in both Type 1 and T2DM. This phenomenon has been attributed to intra-islet defects, like modifications in pancreatic α cell mass or dysfunction in glucagon’s secretion. Emerging evidence has shown that chronic hyperglycaemia provokes changes in the Langerhans’ islets cytoarchitecture, including α cell hyperplasia, pancreatic beta (β) cell dedifferentiati…
The Effect of High Parathyroid Hormone Concentration on Calcitonin in Patients with Primary Hyperparathyroidism2)
2009
Serum calcitonin (CT), parathyroid hormone (PTH), and calcium levels were measured in 23 patients with primary hyperparathyroidism. PTH was determined by a midregion (M-RIA) and a carboxyl-terminal (C-RIA) specific PTH-RIA. Only 2 patients had elevated CT levels. In contrast to the findings in 46 healthy controls, the CT levels did not correlate with calcium levels. Patients who had the highest iPTH values showed a negative correlation between CT and iPTH (M-RIA (n = 7): R = -1.0000, p less than 0.001; C-RIA (n = 13): R = -0.5604, p less than 0.05). The results of the C-RIA were subtracted from those of the M-RIA. In 12 patients with the highest levels of intact PTH (M-RIA - C-RIA), serum P…
New biological aspects of Chromogranin A-derived peptides: Focus on vasostatins
2007
Chromogranin A (CgA), one component of the granin family, represents the major soluble protein co-stored and co-released with catecholamines, within chromaffin cells secretory granules. It is considered a diagnostic and prognostic marker of several diseases, including a variety of tumours and cardiac heart failure. It also represents a precursor of biologically active fragments, generated after proteolytic cleavage at the level of the multiple pairs of dibasic sites which enrich its sequence. CgA, and its derived fragments show an old evolutionary history being ubiquitously present throughout the animal word, from mammals to invertebrates. Their biological functions include control of hormo…
Long-term function of porcine islets and single cells embedded in barium-alginate matrix.
1993
The influence of alginate-embedding on the maintenance of functioning and morphological integrity in long-term culture of isolated porcine islets and islet cells was studied. Free-floating islets and islet cells served for control. Function was tested after the 1st, 2nd and 4th week. Basal and glucose-stimulated insulin secretion of embedded islets decreased slightly, but significantly after the first week (from 4.39 +/- 0.64 to 2.87 +/- 0.47 at normal and from 11.96 +/- 1.44 to 4.76 +/- 0.78 microU pro 24 h pro islet at elevated glucose concentration, p < 0.05 and < 0.01, resp.) and remained unchanged thereafter. Glucose-stimulation resulted in significant increases in insulin secretion at…
HGH secretion after oral application of l-Dopa and l-Carbiodopa
1976
The stimulatory effect of L-Dopa and L-Carbidopa (Nacom) on HGH secretion was determined in 12 children of normal height aged from 6 to 14 years. Each child received a standard dose of 250 mg L-Dopa and 25 mg L-Carbidopa p.o. HGH concentration in the serum was determined at standard intervals. All subjects showed a sufficient increase of HGH. The mean value was 19.6 ng/ml. According to the maximum values of the HGH concentration the sample can be divided into two groups; the first group reached the highest values after 20--40 min, the second one after 60--90 min. On evaluation of the curve of the mean values it appears that 2 blood samples taken 40 and 90 min after the ingestion of L-Dopa a…
Zeitlicher Ablauf der ACTH-induzierten Stimulierung der Corticosteroidbiosynthese
1969
The time course of ACTH action was studied during incubation of quartered rat adrenals by estimation of corticosterone production and secretion rates. The results suggest a two step action of ACTH during the acute stimulation of corticosteroid biosynthesis: A modest initial stimulation was observed within the first 30 min of exposure to ACTH which was overlapped by a marked secondary stimulation between 30 and 60 min.
Glucagon-Like Peptide-1 Modulates Neurally-Evoked Mucosal Chloride Secretion in Guinea Pig Small Intestine In Vitro.
2012
Glucagon-like peptide-1 (GLP-1) acts at the G protein-coupled receptor, GLP-1R, to stimulate secretion of insulin and to inhibit secretion of glucagon and gastric acid. Involvement in mucosal secretory physiology has received negligible attention. We aimed to study involvement of GLP-1 in mucosal chloride secretion in the small intestine. Ussing chamber methods, in concert with transmural electrical field stimulation (EFS), were used to study actions on neurogenic chloride secretion. ELISA was used to study GLP-1R effects on neural release of acetylcholine (ACh). Intramural localization of GLP-1R was assessed with immunohistochemistry. Application of GLP-1 to serosal or mucosal sides of fla…