Aims: To investigate the role of arcuate glucokinase (GK) in the regulation of glucose homeostasis.
Materials And Methods: A recombinant adeno-associated virus expressing either GK or an antisense GK construct was used to alter GK activity specifically in the hypothalamic arcuate nucleus (arc). GK activity in this nucleus was also increased by stereotactic injection of the GK activator, compound A. The effect of altered arc GK activity on glucose homeostasis was subsequently investigated using glucose and insulin tolerance tests.
Results: Increased GK activity specifically within the arc increased insulin secretion and improved glucose tolerance in rats during oral glucose tolerance tests. Decreased GK activity in this nucleus reduced insulin secretion and increased glucose levels during the same tests. Insulin sensitivity was not affected in either case. The effect of arc GK was maintained in a model of type 2 diabetes.
Conclusions: These results demonstrate a role for arc GK in systemic glucose homeostasis.
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http://dx.doi.org/10.1111/dom.13359 | DOI Listing |
JCEM Case Rep
February 2025
Clinica Medica 3, Department of Medicine-DIMED, University Hospital of Padova, Padova 35128, Italy.
Growth hormone (GH) secretion by the pituitary is regulated by stimulatory and inhibitory pathways such as growth hormone releasing hormone (GHRH) and somatostatin, respectively, being also modulated by different neurotransmitters acting at the hypothalamic/pituitary level. The pineal gland hormone melatonin regulates GH secretion in many mammals, including humans, although its role in modulating GH secretion has been debated. We describe the case of a young woman chronically taking melatonin for sleep disturbances, referring to her general practitioner for flushing that appeared just after starting melatonin intake.
View Article and Find Full Text PDFDiabetol Int
January 2025
First Department of Medicine, Wakayama Medical University, 811‑1 Kimi‑idera, Wakayama, 641‑8509 Japan.
Sacubitril/valsartan, an angiotensin receptor neprilysin inhibitor (ARNI), is becoming more common in the treatment of heart failure and hypertension. Neprilysin is highly expressed in the renal tubules, and reports have shown increases in urinary C-peptide reactivity (CPR) levels after administration of ARNI. However, the effect of ARNI on serum CPR levels, a critical marker of insulin secretion in diabetes, remains underexplored.
View Article and Find Full Text PDFIntroduction: Type 1 diabetes is often accompanied by autoimmune thyroid disease. We aimed to investigate the clinical characteristics of Japanese patients with acute-onset type 1 diabetes and thyroid autoantibodies, focusing on decreased endogenous insulin secretion.
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Diabetol Int
January 2025
Department of Endocrinology, Metabolism and Nephrology, Graduate School of Medicine, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-Ku, Tokyo, 113-8603 Japan.
Type 2 diabetes (T2D) is a polygenic disease, and the development of animal models by selective breeding is crucial for understanding its etiology, pathophysiology, complications, and treatments. We recently developed a new T2D model, the Oikawa-Nagao (ON) mouse, by selectively breeding mice with inferior glucose tolerance [diabetes-prone (ON mouse DP®; ON-DP) strain] and superior glucose tolerance [diabetes-resistant (ON mouse DR®; ON-DR) strain] on a high-fat diet. ON-DP mice are predisposed to develop diabetes and obesity after being fed a high-fat diet, compared to ON-DR mice.
View Article and Find Full Text PDFDiabetol Int
January 2025
Department of Endocrinology, Metabolism and Diabetes, Faculty of Medicine, Kindai University, 377-2, Ohnohigashi, Osaka-Sayama, Osaka 589-8511 Japan.
Insulin treatment should be introduced in patients with slowly progressive type 1 diabetes (SPIDDM; definite), according to the revised diagnostic criteria of SPIDDM (2023). In contrast, SPIDDM (probable) patients are in a non-insulin-dependent state; therefore, a more flexible treatment can be considered, although sulfonylurea agents should be avoided. Insulin treatment has been shown to maintain endogenous insulin secretion capacity in SPIDDM (probable); however, this does not mean that all SPIDDM (probable) patients should use insulin from the early phase.
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