Short-term fasting promotes insulin expression in rat hypothalamus.

In the hypothalamus, insulin takes on many roles involved in energy homoeostasis. Therefore, the aim of this study was to examine hypothalamic insulin expression during the initial phase of the metabolic response to fasting. Hypothalamic insulin content was assessed by both radioimmunoassay and Western blot. The relative expression of insulin mRNA was examined by qPCR. Immunofluorescence and immunohistochemistry were used to determine the distribution of insulin immunopositivity in the hypothalamus. After 6-h fasting, both glucose and insulin levels were decreased in serum but not in the cerebrospinal fluid. Our study showed for the first time that, while the concentration of circulating glucose and insulin decreased, both insulin mRNA expression and insulin content in the hypothalamic parenchyma were increased after short-term fasting. Increased insulin immunopositivity was detected specifically in the neurons of the hypothalamic periventricular nucleus and in the ependymal cells of fasting animals. These novel findings point to the complexity of mechanisms regulating insulin expression in the CNS in general and in the hypothalamus in particular.

Glycoforms of CA125 antigen as a possible cancer marker.

CA125, a coelomic epithelium-related antigen, is expressed in both normal and pathological conditions. In this study, we compared the glycosylation of CA125 antigen from amniotic fluid and the ovarian carcinoma cell line OVCAR-3, in order to detect possible differences as a specific marker of their origin. Antigens from both sources were radiolabelled and subsequently subjected to the affinity chromatography, using plant lectins differing in carbohydrate specificity as ligands. A common chromatographic scheme was applied to all columns, i.e. they were eluted with: a) washing buffer to wash out non-bound and low-affinity bound fractions, b) a solution of inhibitory sugar and c) a low pH buffer, to release the high affinity bound fractions. CA125 antigen from each source was found to be heterogeneous in respect to the existence of multiple glycoforms, with O-linked glycan chains predominating. However, the binding patterns of both N- and O-linked glycan-reactive lectins indicated distinct differences in carbohydrate composition between CA125 antigen isolated from amniotic fluid and OVCAR-3 cell line. The observed specificites of CA125-oligosaccharide chains might be of special importance from the biomedical aspect, in terms of their possible use for clinical evaluation of gynecological functions in health and disease.