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Gonadotropin-releasing hormone-I (GnRH-I), present in the mammalian hypothalamus, regulates reproduction. In this study we demonstrate, for the first time, that an additional isoform of GnRH, [His5, Trp7, Tyr8] GnRH-I (GnRH-II) is present in the brain of the mouse, rat and human. Human and rat brain extracts contain two isoforms of GnRH, GnRH-I and GnRH-II, which exhibited identical chromatographic properties to the respective synthetic peptides, in high performance liquid chromatography. Using immunohistochemical techniques we have found that GnRH-II is present in neuronal cells that are localized mainly in the periaqueductal area as well as in the oculomotor and red nuclei of the midbrain. It is of interest to note that in the hypogonadal mouse, although the GnRH-I gene is deleted, GnRH-II is present. Substantial concentrations of GnRH-II are also present in the hypothalamus and stored in the human pituitary stalk or in the mouse median eminence. By using reverse transcription (RT)-PCR we have also found that while GnRH-II is not expressed in the cerebellum, it is expressed in all three structures of the brain stem: midbrain, pons and medulla oblongata.

Twelve different genes for mucin have been described. MUC5AC and MUC6 encode the secreted apomucins of the stomach. A gradient from the surface epithelium (foveola) to the glands is typical for MUC5AC synthesis, whereas a gradient in the opposite direction was found for MUC6. Our goal was to determine the distribution of MUC5AC and MUC6 in the postoperative stomach, with relation to the H. pylori status. Gastric corpus biopsy specimens from patients who underwent partial gastrectomy were examined by immunohistochemistry for mucin gene (MUC5AC and MUC6) apoproteins. We used polyclonal antibodies for amino acid tandem repeats of both proteins. A scoring system (0-3) was used to assess staining intensity at four sites: the lumen, the foveola, the mucous neck cells, and the glands. Helicobacter pylori status was determined by histology and rapid urease test and was considered positive or negative when both tests were positive or negative, respectively. We studied 19 H. pylori-positive and 32 H. pylori-negative patients. No significant change in MUC5AC or MUC6 synthesis and secretion was demonstrated between H. pylori-positive or -negative patients. A gradient similar to that shown for the intact stomach (from the surface epithelium to the glands) for MUC5AC protein and an increase of MUC6 protein presentation from the mucous neck cell to the glands were demonstrated. The pattern of MUC5AC protein synthesis was not different between H. pylori-positive and -negative patients in the postoperative stomach. MUC6 expression was higher in the foveola in H. pylori-positive patients, whereas there was no difference in the other cell layers.

Background/objective Helicobacter pylori colonizes the gastric mucous gel layer, the surface epithelium and glands. It has been shown that H. pylori infection causes aberrant expression of gastric mucins MUC 5 and MUC 6. This study aimed to determine the distribution of MUC 5 and MUC 6 in the gastric antrum of dyspeptic patients, and to investigate changes in this pattern in the presence of H. pylori and after successful eradication. Materials and methods Gastric antrum biopsy specimens were examined by immunohistochemistry for mucin gene (MUC 5 and MUC 6) expression. Polyclonal antibodies were used to detect amino acid tandem repeats of each protein. A scoring system (0-3) was used to assess staining intensity at three sites: foveola, mucous neck cells and glands. H. pylori status was determined by histology and rapid urease test, and considered positive or negative when both tests were positive or negative, respectively. The study included 49 patients positive for H. pylori, in 36 of whom successful eradication was performed, and 11 H. pylori-negative patients. Results There was a gradient of MUC 5 expression, higher to lower, from the surface to the glands, which was more pronounced before eradication. Increased MUC 5 synthesis in the mucous neck cells and in the glands was found after H. pylori eradication (P = 0.016). MUC 6 was synthesized in the glands more than in the mucous neck cells or foveola. MUC 6 was also secreted into the lumen and probably comprised the superficial part of the unstirred mucous layer. Conclusion The change in MUC 5 synthesis may reflect H. pylori colonization.

The localization of the recently identified GH-releasing hormone (GHRH) in the human hypothalamus and pituitary stalk was determined by microdissection techniques and a specific RIA for GHRH. The highest concentrations of GHRH immunoreactivity (IR-GHRH) in the hypothalamus were found in the area of the infundibular nucleus (83 +/- 4 ng/mg protein; average +/- range). Lower quantities were found in other hypothalamic regions. Very high concentrations of IR-GHRH were present in the upper portion of the pituitary stalk (1454 +/- 48 ng/mg protein), and they decreased gradually toward the distal end of the stalk (21 +/- 3 ng/mg). This concentration gradient suggests that the peptide reaches the anterior pituitary mainly by way of the long portal vessels. Somatostatin, the second neuropeptide involved in the regulation of GH secretion from the anterior pituitary, had a pattern of distribution along the pituitary stalk very similar to that of IR-GHRH.