Production of corticosteroid hormones in vitro by adrenals in rats with streptozotocin-induced diabetes

Long-term treatment with roflumilast improves learning of fear extinction memory and anxiety-like response in a type-1 diabetes mellitus animal model

Diabetic encephalopathy is related to serious damage to the Central Nervous System leading to several disturbances in memory processing and emotions. It is known that the cyclic adenosine 3',5'-monophosphate (cAMP) responsive element-binding protein (CREB) pathway participates in neuronal plasticity and prevention of neuroinflammation, as well as the mediation of learning/memory processes and emotions in brain areas such as the hippocampus (HIP) and prefrontal cortex (PFC). We aimed to investigate the effect of acute (one injection) and long-term treatment (21 days) with roflumilast (ROF; i.p.; 0, 0.01, 0.03, 0.1 mg/kg), a drug able to inhibit the enzyme phosphodiesterase-4 (PDE-4) responsible for cAMP hydrolysis, on parameters related to the acquisition of fear extinction memory and anxiety-like responses in animals with type-1 diabetes mellitus (T1DM) induced through one injection of streptozotocin (60 mg/kg; ip; STZ animals). When we performed acute treatment, no difference was observed between all the groups when resubmitted to the same context paired with an aversive stimulus (footshock) or to a neutral context. In contrast, long-term treatment was able to improve learning of extinction fear memory and discriminating between a conditioned and neutral context. Moreover, this treatment decreased the pronounced anxiety-like response of STZ animals. In addition, there was an increase in the product of the CREB signaling pathway, the pro brain-derived neurotrophic factor, in the HIP and PFC of these animals. The treatment did not impair glycemic control, whereas it decreased the animal's blood glucose levels. To conclude, these findings suggest that ROF treatment repositioning has potential for future translational investigations involving diabetic patients considering its beneficial effects on emotional processes related to fear memory and anxiety, in addition to improvement of glycemic control.

A single injection of pregabalin induces short- and long-term beneficial effects on fear memory and anxiety-like behavior in rats with experimental type-1 diabetes mellitus

Anxiety Disorders and Posttraumatic Stress Disorders (PTSD) associated with type-1 diabetes mellitus (T1DM) are increasingly common comorbidities and the treatment is quite challenging. In that sense, evidence indicates that the anticonvulsant pregabalin is highly effective in treating severe cases of anxiety, as well as PTSD and diabetic neuropathic pain which is also very prevalent in T1DM. Herein, the short- and long-term effects of a single injection of pregabalin on the acquisition of a fear extinction memory and parameters of anxiety in induced-T1DM animals were investigated. For that, we used the contextual fear conditioning (CFC) and elevated plus maze paradigms, respectively. A putative antioxidant activity was also evaluated. Our findings demonstrated that induced-T1DM animals presented greater expression of fear memory, difficulty in extinguishing this fear memory, associated with a more pronounced anxiety-like response. Pregabalin was able to induce a short and long-lasting effect by facilitating the acquisition of the fear extinction memory and inducing a later anxiolytic-like effect. Also, the increased lipid peroxidation levels in the hippocampus and prefrontal cortex of induced-T1DM rats were reduced after pregabalin injection, while the decreased levels of reduced glutathione were increased in the hippocampus. Despite the need for more studies to understand the mechanism of action of pregabalin under these conditions, our data demonstrate for the first time that a single injection of pregabalin in a specific time window was able to improve behavioral parameters in addition to inducing neuroprotective effect. Thus, pregabalin has potential worth exploring for the treatment of PTSD and/or Anxiety associated with T1DM.

[Hypercorticism during streptozotocin diabetes and mifepristone administration: the role of cyclic adenosine monophosphate]

It was studed basal and ACTH-stimulated production of cyclic adenosine monophosphate (cAMP) and corticosteroid hormones (progesterone and corticosterone) in rat adrenals in vitro under streptozotocin diabetes, in conditions of mifepristone administration and their combination. It was shown that in streptozotocin diabetes animals, both the basal and adrenocorticotropic hormone (ACTH) stimulated cAMP production significantly increased; this was accompanied by the increase in basal and ACTH-stimulated progesterone and corticosterone production in rat adrenals in vitro. Repeated administration of mifepristone to control and diabetic rats caused an increase mainly in ACTH-stimulated production of the main glucocorticoid hormone, corticosterone, without additional changes in the cAMP level. The results obtained suggest activation of two mechanisms of steroidogenesis enhancement in experimental animals. In rats with streptozotocin diabetes, both basal and ACTH-stimulated activity of all stages of steroidogenesis increase, which is mediated by the increased formation of cAMP as second messenger mediating the ACTH action on adrenocortical cells. Prolonged administration of mifepristone to control and diabetic rats resulted in increased activity of only late stages of steroidogenesis with predominant elevation of synthesis of physiologically active hormone corticosterone without additional changes in cAMP production level.

[Correlation analysis of serum progesterone with clinical indicators and common traditional Chinese medicine syndrome types in male type 2 diabetic patients]

OBJECTIVE

To analyze the correlation of serum progesterone (PROG) level with blood biochemical parameters and common traditional Chinese medicine (TCM) syndromes in male patients with type 2 diabetes mellitus (T2DM).

METHODS

We collected the clinical data of 192 male patients with T2DM, who were admitted in the Department of Endocrinology, Nanjing Hospital of Chinese Medical Affiliated to Nanjing University of Chinese Medicine between January, 2018 and March, 2019. The general clinical data, C-peptide level, blood glucose level, glycated hemoglobin (HbA1c), HOMA, blood lipid level, and sex hormones were compared between the patients with normal PROG and elevated PROG levels and also between the patients with two common TCM syndromes, namely qi and Yin deficiency syndrome and damp- heat accumulation in the spleen syndrome. We further compared the sex hormones, C-peptide level, HOMA, HbA1c, and blood glucose level among the patients with the two TCM syndromes having normal or elevated PROG levels.

RESULTS

Compared with those in patients with normal PROG level, BMI, C-peptide, HOMA-β, and HOMA2-IR were significantly lowered and HOMA-IS, E2, and T were significantly increased in patients with elevated PROG level; no statistical differences were found in age, disease duration, waist-to-hip ratio (WHR), smoking history, blood pressure, blood glucose, blood lipids, HbA1c, LH, FSH or PRL between the two groups. Compared with the patients with damp-heat accumulation syndrome group, the patients with qi and Yin deficiency syndrome were older and had a longer disease duration, a greater BMI, and higher levels of PROG, C-Peptide, HOMA-β, HOMA2-IR and HOMA-IS, but the smoking history, WHR, HbA1c, blood glucose, and sex hormone levels were comparable between the two groups. Among the 4 groups of patients with different PROG levels and TCM syndromes, significant differences were found in the levels of C-peptide, HOMA-β, HOMA-IS, HOMA2-IR, PROG, E2, T, LH and FSH, and the patients with qi and Yin deficiency syndrome as well as an elevated PROG level had the lowest C-peptide level, HOMA-β and HOMA2-IR and the highest HOMA-IS, PROG, E2, T, LH and FSH.

CONCLUSIONS

An elevated PROG level is closely related to islet cell dysfunction and TCM syndrome types in male patients with T2DM.

Effect of Mifepristone on Corticosteroid Production in Vitro by Adrenal Glands of Rats with Streptozotocin Diabetes

Changes in pregnenolone and corticosterone production by the adrenal glands of normoglycemic rats receiving the course of intraperitoneal mifepristone or NaCl administration were co-directed, but differed in magnitude. In rats with hyperglycemia, corticosteroid production increased after NaCl administration over 5 days and returned to the initial values after 15-day administration. On the contrary, pregnenolone and corticosterone production was suppressed after 5-day course of mifepristone, but significantly increased after mifepristone administration for 15 days. Intraperitoneal mifepristone administration almost completely abolished the response of rat adrenal glands with normo- and hyperglycemia to ACTH in vitro; this effect did not depend on the duration of administration.