Pinealectomy Increases and Exogenous Melatonin Decreases Leptin Production in Rat Anterior Pituitary Cells: an Immunohistochemical Study

Summary Melatonin, the main hormone of the pineal gland, informs the body about the environmental light and darkness regimen, which in turn contributes to the photoperiodic adaptation of several physiological functions. Leptin, the hormone secreted mainly by adipocytes and some other tissues including the pituitary, informs the brain about the mass of adipose tissue, which plays an important role in energy homeostasis. Melatonin has been shown to decrease circulating leptin levels. It is currently not known whether melatonin has an effect on leptin synthesis in the pituitary. The aim of this study was to immunohistochemically examine the effects of pinealectomy and administration of melatonin on leptin production in the rat anterior pituitary. The pituitary samples obtained from 18 male Wistar rats including sham-pinealectomized, pinealectomized and melatonin-injected pinealectomized groups were immunohistochemically evaluated. Immunostaining of leptin was moderate (3+) in sham-pinealectomized rats, heavy (5+) in pinealectomized rats and low (1+) in melatonin-treated pinealectomized rats, respectively. The present results indicate that pinealectomy induces leptin secretion in anterior pituitary cells, and this increase of leptin synthesis can be prevented by administration of melatonin. Thus, melatonin seems to have both physiological and pharmacological effects on leptin production in the anterior pituitary of male rats

Interrenal cell zonation in the adrenal gland of the goose (Anser anser)

The adrenal medulla in mammalian species is surrounded by a cortex that contains three distinct layers, whereas the cortex and medulla are intermingled in poultry species. The objective of the present study was to determine the distinct zonation changes in the adrenal cortex of geese in various ages using both electron and light microscopy. Adrenal glands were obtained from French Geese (Anser anser) under deep ether anesthesia at posthach day 1, 5, 10, 21 and 30 (n = 5 per day). The cytoplasm of interrenal cells located beneath the adrenal capsule (sub-capsular zone, SCZ) were stained lighter than that of interrenal cells located inside the adrenal gland (inner zone, IZ) and contained several vacuoles for each sampling day. Additionally, unlike IZ cells, SCZ cells contained nuclei that were various shapes and surrounded by irregularly arranged membranes, lipid droplets which were not surrounded by a membrane, mitochondria with mostly shelf-like cristae. The arrangement of SCZ cells appears similar to that of zona glomerulosa and also the arrangement of IZ cells to that of zona fasciculata of mammalian adrenal cortex, suggesting the significant signs of zonation in goose adrenal cortex

On self-propulsion assessment of marine vehicles

Estimation of ship self-propulsion is important for the selection of the propulsion system and the main engine so that the ship can move forward with the required speed. Resistance characteristics of the vessel or the open-water performance of a propeller only are not usually enough to assess the working conditions of the ship. Both in numerical simulations and in experiments; there is a need to treat the propulsion system and the hull as a whole for a better estimation of the self-propulsion parameters. In this study, the self-propulsion points of one submarine (DARPA Suboff) and two surface piercing vessels (KCS and DTC) were obtained with methods based on computational fluid dynamics (CFD) approach. The self-propulsion points were also calculated by a classical engineering approach that makes use of the empirical relations that may be found in the literature. The results were evaluated with respect to the experiments and numerical results generated by other researchers in this field. It was found that the self-propulsion points of traditional ship forms can be very closely approximated with a classical engineering approach, given the basic geometric and the hydrostatic properties of the hull and the propeller. © 2018, Brodarski Institute. All rights reserved

Effects of high dose retinoic acid on TGF-beta 2 expression during pancreatic organogenesis

The aim of this study was to investigate the effects of excess all-trans retinoic acid, a vitamin A metabolite, on pancreatic organogenesis and TGF-beta 2 expression during prenatal development in rats

The effect of cold atmospheric plasma (NO) alone and in combination with NPH insulin on the full-thickness excisional wound healing in a diabetic rat model

This study was planned to investigate an alternative treatment modality in diabetic wound healing. In this experimental study, the efficacy of both cold atmospheric plasma/nitric oxide (NO) and NPH insulin ointment, recently known to have beneficial effects on wound healing, was investigated in diabetic wound healing. Twenty-four (24) diabetic rats were divided into four groups DC, DI, DNO and DINO (diabetic control, diabetic insulin, diabetic nitric oxide, diabetic insulin + nitric oxide groups). No treatment was applied to the DC group, NPH insulin was applied to the DI group, CAP/NO was applied to the DNO group, and CAP/NO + NPH insulin was applied to the DINO group once daily for 14 days. The wound area reduction and the wound contraction rate were calculated on the basis of the tissue sections taken, and histopathological and genetic analyses were carried out. Compared to the control group, exogenous NO gas was found to be a potent antibacterial agent in the diabetic wound healing, causing a reduction in the wound area (P = 0.034), an increased contraction rate (P = 0.021), epithelialisation (P = 0.02), collagen organisation (P = 0.006) and a reduction in the number of inflammatory cells (P = 0.002). A significant increase in the expression of IL-8 mRNA was observed (P = 0.026). It was concluded that NPH insulin alone contributes to wound healing, but it is not necessary to use it together with exogenous NO gas