Since Rinehart and Farquhar reported the presence of agranulated cells in the anterior pituitary gland in 1953, the functions of the folliculo-stellate cell remain to be clarified. Intercellular junctions have been described in the monkey, rat, and teleost anterior pituitary glands, indicating the existence of cell-to-cell communication within the organ. We pointed to their possible role in the rapid dissemination of information through a complex interconnecting system of follicles involving gap junctions. The gap junctional/folliculo-stellate cellular network was essential in the maturation and regulation of the pituitary gland system such as the hypothalamic-pituitary-gonadal axis. It has been was shown that a network participated in the conduction of electrophysiological information over a long distance using the ion Ca ϩϩ , which propagates to other folliculo-stellate cells by signaling through gap junctions. Sixty-day-old male rats were used in this study for light microscopic immunohistochemistry of S-100 protein, type I collagen, and connexin 43, and for electron microscopy to observe the morphological relationships between the cellular networks of folliculo-stellate cells and granulated pituitary cells. Clusters of anti-S-100 protein-positive cells were clearly observed in a region of the hypophysis tentatively named the transition zone. Anti-S-100 protein-positive cells and their cytoplasmic processes were also present in the anterior lobe and assembled together to form follicular lumina. Type I collagen was clearly shown outlining the incomplete lobular or ductule-like structure making cell cords in the anterior pituitary gland. Numerous microvilli were present within the follicular lumen while around the lumina, junctional specializations including gap junctions were positive for the connexin 43 protein. A nonuniform distribution of the connexin 43-positive sites were observed. Small or dot-shaped positive sites were noted where two clusters of cells were connected; the cells were identified as S-100 cells. Double immunohistochemical staining of the connexin 43 and growth hormone (GH) or connexin 43 and luteinizing hormone (LH) was also performed, demonstrating no direct relationship between the connexin 43 and either the GH or LH cells. These findings indicate that there are two kinds of messages necessary for the hormone release in the pituitary gland. One is via the portal vein system, the other is through the gap junction-mediated networks of folliculo-stellate cells. The granulated cells directly associate with cell membrane of folliculo-stellate cells are able to discharge secretory granules through communication via gap junctions, while those granulated cells that are more distant from the folliculo-stellate cells are only able to discharge hormones via the pituitary hormone-releasing hormone from the portal vein system. Anat Rec Part A 278A: 462-473, 2004.

Failure criteria of the heat‐sealed part of oriented polypropylene (OPP) and cast polypropylene (CPP) heat seals made by an impulse type heat‐sealing machine were investigated. Circular notches and precracks were introduced to direct failure to specific areas such as inside the seal, at the border, or at the unsealed part. The notched strength as a function of heat‐sealing temperature revealed that the seals were stronger in the transverse direction (TD) as compared with the machine direction (MD). Tensile failure that occurred inside the heat seal is more sensitive to sealing temperature, whereas that at the unsealed part is immune. The stress intensity factor (K1) is generally higher along the TD. At high sealing temperatures, i.e. above 150°C, orientation in the OPP film is relaxed and this results in consistently low mechanical properties at this temperature range. This morphology was revealed by studies of crystalline orientation state and FTIR imaging. POLYM. ENG. SCI., 46:205–214, 2006. © 2005 Society of Plastics Engineers

The distribution of LH-RH-positive nerve fibers in the median eminence was demonstrated in the 1970s and 1980s. A few LH-RH fibers have been reported to be present in the adjacent pars tuberalis of the pituitary, but their functional significance has not been clarified and still remains enigmatic. Adult male Wistar-Imamichi rats were separated into two groups: one for immunohistochemistry of LH-RH and S-100 protein (for the identification of folliculo-stellate cells) and the other for electron microscopy. For both immunohistochemistry and electron microscopy, the specimens obtained contained the pituitary gland connected with the hypothalamus. Numerous LH-RH-positive fibers were observed as tiny lines with several varicosities both on the primary vascular plexus and in the hypothalamus corresponding to the posterior half of the portal vein area. LH-RH-positive fibers were also noted around S-100-positive cells in the pars tuberalis. Weakly reactive S-100 cells were scattered in the pars tuberalis in the midsagittal plane, while clusters of strong reactive elements occurred 100-300 microm from the center. Similar observations were made using fluorescence immunohistochemistry for LH-RH and S-100, and at the electron-microscopic level. At the posterior portion of the portal vein system, bundles of the LH-RH-immunoreactive fibers invaded the pars tuberalis and terminated on agranular cells. Gap junctions were clearly seen among agranular cells corresponding to folliculo-stellate cells. It is postulated that the LH-RH message might be transmitted not only by the established hypophyseal portal vein system but also via the folliculo-stellate cells in the pars tuberalis to aid in the modulation of LH release.

Aims/Methods: To investigate whether smoking affects the serum level of leptin, 708 male workers aged 25–65 years old were cross-sectionally surveyed. Results: Multiple regression analysis indicated that among the various parameters examined, the level of leptin was positively associated with the body mass index and the levels of insulin, total cholesterol and uric acid, and was inversely associated with physical activity and the level of creatinine. The partial correlation coefficient of leptin was highest against the body mass index (r = 0.40), followed by insulin (0.29) and physical activity (–0.14), after adjustment for other leptin-related variables. However, no association was observed between the level of leptin and smoking (0.05), alcohol consumption (0.09) or age (0.09). Conclusions: The findings suggest that among life-style habits, physical activity, but not smoking or alcohol consumption, significantly affects the serum level of leptin in Japanese men.

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