Increasing evidence suggests an important role of the insulin-like growth factor (IGF)-IGF binding protein (IGFBP) axis in the maintenance of normal glucose and lipid metabolism. Significant changes occur in the local IGF-I-IGFBPs environment in response to the diabetic milieu. A significant reduction of serum IGF-I levels was observed in patients with type 1 diabetes mellitus (T1DM). Inversely, considerably increased serum levels of IGF-I and IGFBP-3 levels were detected in individuals with glucose intolerance including T2DM. Recently, several prospective studies indicated that baseline levels of IGF-I and IGFBPs are associated with the development of diabetes. These findings suggest that disturbances in insulin and IGF-I-IGFBP axis can affect the development of glucose intolerance including diabetes.

Adriamycin is an anti-cancer drug, effective against a wide range of cancers. However, its clinical application is limited by its cardiotoxicity. A number of reports suggest that adriamycin induces bodyweight loss also. The aim of this study was to investigate the effect of adriamycin on adipogenesis as bodyweight chancges can be directly correlated with adipocytes. Fat accumulation in 3T3-L1 pre-adipocytes, as a result of adipogenesis was detected using oil red O staining. We performed western immunoblot for the expression of adipocyte differentiation related genes to analyze the molecular mechanism of adriamycin-mediated inhibition of adipogenesis. Over-expression of target gene was done by using recombinant adenoviruses. Adriamycin inhibited adipogenesis in a dose-dependent manner. It was observed that adriamycin down-regulated the expression of PPARγ. Moreover, up-stream elements of PPARγ were also found to be down-regulated by adriamycin. Adriamycin might prevent bodyweight gain through inbibition of adipogenesis by the down-regulation of PPARγ and its up-stream transcriptional regulators like C/EBPβ and KLF4. To reverse the adriamycin-mediated inhibition of adipogenesis, PPARγ was over-expressed by adenoviral mediated gene delivery. Over-expression of PPARγ partially restored adipogenesis. Moreover, the early regulators of adipogenesis were also found to be restored after the over-expression of PPARγ. Adriamycin down-regulates the expression of PPARγ which leads to prevention of bodyweight gain through inhibition of adipogenesis. Activation of PPARγ by either adenoviral mediated gene delivery or by using PPARγ agonist may be useful in controlling the bodyweight loss.

Alpha-1 antitrypsin (AAT), an alpha globulin glycoprotein, is a member of the serine protease inhibitor (serpin) superfamily. The clinical significance of AAT is highlighted by AAT deficiency. Genetic deficiency of AAT can present as several neutrophilic diseases associated with emphysema, liver cirrhosis, panniculitis, and systemic vasculitis. Recently, animal and human studies have shown that AAT can control inflammatory, immunological, and tissue-protective responses. In addition, AAT treatment can prevent overt hyperglycemia, increase insulin secretion, and reduce cytokine-mediated apoptosis of pancreatic β-cells in diabetes. These multifunctional roles of AAT draw attention to the glycoprotein's therapeutic potential for many inflammatory and autoimmune diseases beyond AAT deficiency. As underlying mechanisms, recent studies have suggested the importance of serine protease inhibitory activity of AAT in obesity-associated insulin resistance, chronic obstructive pulmonary disease, and cystic fibrosis. In this review, we explore the multiple functions of AAT, in particular, the anti-inflammatory and serine protease inhibitory functions, and AAT's therapeutic potential in a variety of human diseases through published literature.

Vitamin D is a versatile signalling molecule that plays a critical role in calcium homeostasis. There are several studies showing the genomic action of vitamin D in the control of reproduction; however, the quick non-genomic action of vitamin D at the hypothalamic level is not well understood. Therefore, to investigate the effect of vitamin D on juvenile gonadotrophin-releasing hormone (GnRH) neurons, excitatory neurotransmitter receptor agonists N-methyl-D-aspartate (NMDA, 30 μM) and kainate (10 μM) were applied in the absence or in the presence of vitamin D3 (VitaD3, 10 nM). The NMDA-mediated responses were decreased by VitaD3 in the absence and in the presence of tetrodotoxin (TTX), a sodium-channel blocker, with the mean relative inward current being 0.56 ± 0.07 and 0.66 ± 0.07 (P < 0.05), respectively. In addition, VitaD3 induced a decrease in the frequency of gamma-aminobutyric acid mediated (GABAergic) spontaneous postsynaptic currents and spontaneous postsynaptic currents induced by NMDA application with a mean relative frequency of 0.595 ± 0.07 and 0.56 ± 0.09, respectively. Further, VitaD3 decreased the kainate-induced inward currents in the absence and in the presence of TTX with a relative inward current of 0.64 ± 0.06 and 0.68 ± 0.06, respectively (P < 0.05). These results suggest that VitaD3 has a non-genomic action and partially inhibits the NMDA and kainate receptor-mediated actions of GnRH neurons, suggesting that VitaD3 may regulate the hypothalamic–pituitary–gonadal (HPG) axis at the time of pubertal development.

Kim MS, et al. J Korean Med Sci. 2007 Aug;22(4):616-620. http://dx.doi.org/10.3346/jkms.2007.22.4.616

Kim MS, et al. J Korean Med Sci. 2017 Jun;32(6):985-991. https://doi.org/10.3346/jkms.2017.32.6.985