Differential influences of gender and physiological status on calcium dynamics and prolactin gene expression in rat mammotropes

The rate of prolactin (PRL) secretion is influenced by the gender and physiological state of an animal, but little is known about the mechanisms involved. In the present study, we assessed possible contributions of Ca²⁺ dynamics and PRL gene expression to these differences. This was accomplished by monitoring spontaneous [Ca²⁺]_i changes and PRL promotor-driven reporter activity in pituitary cultures derived from rats comprising a broad spectrum of PRL secretory capacities: male, cycling female, and lactating rats. We found that Ca²⁺ oscillatory activity exhibited a rank order of lactating > cycling females > males, consistent with the reported secretory capacities of mammotropes from these sources. Interestingly, we observed that the basal level of PRL promotor-driven reporter activity was the same for all three models, but that mammotropes from males were the most responsive to stimulation of PRL gene expression by elevation of [Ca²⁺]_i. Collectively, our findings reveal gender-and state-specific differences in Ca²⁺ dynamics and induction of PRL gene expression. These likely contribute to reported differences in secretory capacity.     

A milk-borne factor inhibits mammotrope differentiation in the neonatal rat

Within the first few days of neonatal life in the rat, a milk-borne peptide is transferred to the neonatal circulation and transported to the pituitary gland where it acts directly to induce final differentiation of mammotropes. As we were attempting to purify this stimulatory peptide, we separated an antagonistic activity that serves as the focus of the present study. Milk obtained on days 2–3 of lactation was subjected to pH fractionation followed by acetone precipitation to yield two fractions that stimulated and inhibited, respectively, mammotrope differentiation in cultures of neonatal pituitary cells. The stimulatory agent more than doubled the proportion of prolactin secretors in those cultures, whereas the inhibitory agent exerted the opposite effect when tested alone. Moreover, the inhibitory agent severely attenuated mammotrope differentiation evoked by the stimulatory fraction or by basic FGF, an established inducer of this developmental phenomenon. The discovery of a milk-borne inhibitor, coupled with the previously described milk stimulatory factor, indicates that maternal control of mammotrope differentiation is considerably more sophisticated than previously believed.     

Effect of repaglinide on insulin secretion in islets from rats infused for two days with a hypertonic solution of d-glucose

This study investigates the insulin secretory responsiveness of pancreatic islets to repaglinide in an experimental model of B-cell glucose incompetence. Rats were infused for 2 d with a 1.67 M solution of d-glucose administered at a rate close to 2.8 mL/h. This resulted in a modest rise in glycemia, a severe increase in plasma insulin concentration, an increased sensitivity of B-cells to adrenergic stress, an abnormally high insulin output from isolated islets perifused in the presence of 16.7 mM d-glucose, and a paradoxical transient increase in insulin release from the islets in response to a fall in hexose concentration. The early increment in insulin output evoked by repaglinide, in the presence of 16.7 mM d-glucose, was not lower in the islets from glucose-infused rats than in those from control rats. Moreover, when the meglitinide analog was administered concomitantly with the removal of d-glucose from the perifusion medium, the early response to repaglinide was further increased. Even after 24 min of glucose deprivation, the output of insulin by the islets from glucose-infused rats was higher in the presence of repaglinide than in its absence. These findings indicate that, in this model of B-cell dysfunction, the secretory responsiveness to repaglinide, as distinct from that to glucose, is fully preserved. Therefore, when taken into consideration together with prior observations, these findings argue in support of the use of this insulinotropic agent in the treatment of noninsulin-dependent diabetes.     

Melatonin ameliorates low‐grade inflammation and oxidative stress in young Zucker diabetic fatty rats

The aim of this study was to investigate the effects of melatonin on low‐grade inflammation and oxidative stress in young male Zucker diabetic fatty (ZDF) rats, an experimental model of metabolic syndrome and type 2 diabetes mellitus (T2DM). ZDF rats (n = 30) and lean littermates (ZL) (n = 30) were used. At 6 wk of age, both lean and fatty animals were subdivided into three groups, each composed of 10 rats: naive (N), vehicle treated (V), and melatonin treated (M) (10 mg/kg/day) for 6 wk. Vehicle and melatonin were added to the drinking water. Pro‐inflammatory state was evaluated by plasma levels of interleukin‐6 (IL‐6), tumor necrosis factor‐α (TNF‐α), and C‐reactive protein (CRP). Also, oxidative stress was assessed by plasma lipid peroxidation (LPO), both basal and after Fe²⁺/H₂O₂ inducement. ZDF rats exhibited higher levels of IL‐6 (112.4 ± 1.5 pg/mL), TNF‐α (11.0 ± 0.1 pg/mL) and CRP (828 ± 16.0 µg/mL) compared with lean rats (IL‐6, 89.9 ± 1.0, P < 0.01; TNF‐α, 9.7 ± 0.4, P < 0.01; CRP, 508 ± 21.5, P < 0.001). Melatonin lowered IL‐6 (10%, P < 0.05), TNF‐α (10%, P < 0.05), and CRP (21%, P < 0.01). Basal and Fe²⁺/H₂O₂‐induced LPO, expressed as malondialdehyde equivalents (µmol/L), were higher in ZDF rats (basal, 3.2 ± 0.1 versus 2.5 ± 0.1 in ZL, P < 0.01; Fe²⁺/H₂O₂‐induced, 8.7 ± 0.2 versus 5.5 ± 0.3 in ZL; P < 0.001). Melatonin improved basal LPO (15%, P < 0.05) in ZDF rats, and Fe²⁺/H₂O₂‐ induced LPO in both ZL (15.2%, P < 0.01) and ZDF rats (39%, P < 0.001). These results demonstrated that oral melatonin administration ameliorates the pro‐inflammatory state and oxidative stress, which underlie the development of insulin resistance and their consequences, metabolic syndrome, diabetes, and cardiovascular disease.     

Factors associated with pre-hospital and in-hospital delay time in acute myocardial infarction: a 6-year experience

Berglin Blohm M, Hartford M, Karlsson T, Herlitz J (Division of Cardiology, Sahlgrenska University Hospital, Göteborg, Sweden). Factors associated with pre-hospital and in-hospital delay time in acute myocardial infarction: a 6-year experience. J Intern Med 1998; 243 : 243–50.

Objectives

To explore factors associated with delay time prior to hospital admission and in hospital amongst acute myocardial infarction (AMI) patients with particular emphasis on the delay time to the administration of thrombolytic therapy.

Methods

During a 6-year period we prospectively computerized pre-hospital and in-hospital time intervals for AMI patients admitted to the coronary care unit (CCU) direct from the emergency department (ED) or via paramedics, at Sahlgrenska Hospital, Göteborg, Sweden.

Results

Pre-hospital delay: independent predictors of a prolonged delay were increased age (P<> = 0.0007), female sex (P<> = 0.02) and a history of hypertension (P<> = 0.03). For AMI patients who received thrombolytic treatment and the only independent predictor of a prolonged delay was increased age (P<> = 0.005). In-hospital delay: for all AMI patients independent predictors of a prolonged delay were prolonged pre-hospital delay (P < 0.0001), increased age (P= 0.03) and a history of angina (P= 0.002), hypertension (P= 0.01) and diabetes (P= 0.01). For thrombolytic treated AMI patients independent predictors of a prolonged delay were prolonged pre-hospital delay (P < 0.0001), female sex (P= 0.02) and a history of diabetes (P= 0.02).

Conclusion

Risk factors for both pre-hospital and hospital delay time could in AMI be defined although slightly different. Two factors appeared for both, i.e. increasing age and a history of hypertension.

     

The role of CGRP and afferent nerves in the modulation of pancreatic enzyme secretion in the rat

Summary Conclusion Stimulation of pancreatic sensory nerves by capsaicin produced secretory effects probably caused, at least in part, by the release of CGRP. Background In the pancreas calcitonin gene-related peptide (CGRP) has been localized in the sensory nerves, but its physiological role is unknown. This study was undertaken to compare the changes of pancreatic enzyme secretion produced by CGRP and by stimulation or destruction of sensory nerves. Methods To stimulate sensory nerves, low doses of capsaicin (0.25–0.5 mg/kg) were given intraduodenally to the conscious rats with chronic pancreatic fistula. To inactivate sensory nerves high doses of capsaicin (100 mg/kg) were given subcutaneously 10 d before tests. For the in vitro experiments pancreatic slices and isolated pancreatic acini were prepared from intact and capsaicin-denervated rats. Results In conscious rats, CGRP given subcutaneously (5–10 μg/kg) and low doses of capsaicin given intraduodenally reduced basal pancreatic secretion. In isolated pancreatic acini, CGRP (10⁻¹⁰–10⁻⁶ M), but not capsaicin, increased basal or secretagog-stimulated amylase release. In pancreatic slices (containing nerve fibers) capsaicin (10⁻¹⁰–10⁻⁶ M) increased enzyme secretion, and this secretion was abolished by previous inactivation of sensory nerves by this neurotoxin. Capsaicin deactivation did not affect the secretory response of pancreatic acini to CGRP, cerulein, or urecholine. Sensory denervation by capsaicin did not change basal protein secretion, but reduced that produced by feeding or diversion of pancreatic juice to the exterior during first 2 h of the tests.     

Fibroblast growth factor-2 and epidermal growth factor modulate prolactin responses to TRH and dopamine in primary cultures

Fibroblast growth factor-2, (FGF-2) and epidermal growth factor (EGF) are expressed in most tissues of the organism including pituitary, FGF-2 increases PRL levels and PRL mRNA in GH3 cells and primary cultures, and it has been involved in the lactotroph proliferation and hyperplasia. EGF also increases PRL levels in vitro. However, the effects of these two factors in the responses of lactotroph cells to TRH and dopamine (DA) remain to be clarified. In the present work we have studied the modulator activity of FGF-2 and EGF on in vitro PRL in responses to TRH and DA in primary cultures from in vivo vehicle-or estrogen (E2)-treated rats. We have found that FGF-2 (2×10⁻¹¹ M) prevents the EGF-induced dose-dependent increase in PRL levels in control cells, and reversed the EGF-stimulating effects in cells from E2-treated rats. Both FGF-2 (2×10⁻¹¹ M) and EGF (6.6×10⁻⁹ M) significantly increase (>30% and >120%, respectively) the PRL levels in response to TRH (10⁻⁶ 10⁻⁵ M). FGF-2 blocked the inhibitory effects of low doses of DA (10⁻⁹ M). EGF was unable to do so, although markedly increased (>200%) the post-DA PRL rebound. In cells from in vivo E2-treated rats, FGF-2 increased (>50%) the PRL secretion in response to TRH, while EGF reduced responses to high doses of TRH (10⁻⁶, 10⁻⁵ M). In addition, FGF-2 reversed and EGF increased the inhibitory effects of DA. Both FGF-2 and EGF completely blocked the post-DA PRL rebound, in these cells. Taken together our data suggest that FGF-2 and EGF are important regulators of lactotroph responsiveness to TRH and DA in vitro, although their actions are highly dependent on estrogenic milieu.     

Effects of Glucose or Insulin Infusions on Growth Hormone Secretion in Male Red Deer

The growth hormone (GH) secretory pattern in male red deer is associated with the seasonal growth cycle. During this cycle metabolic state changes from weight gain in spring to weight loss in winter. However, short-term metabolic changes due to feeding could also alter the GH pattern. To investigate the effect of such changes on GH secretion, the acute feedback of blood glucose level on the GH secretory pattern was examined. Six yearling male red deer were infused iv with glucose (G; 150 mg/kg/hr) or insulin (I; 30 mU/kg/hr) for a 12-hr period, 1 week apart. GH was measured in jugular venous blood every 10 min, for 12 hr before, during, and 6 hr after the infusions. Glucose, insulin, IGF-1, and haematocrit were also measured. There was no difference (P > 0.05) in glucose levels between G and I prior to infusions (5.8 vs 6.0 mmol/liter, SED = 0.42). Glucose levels rose to 8.7 mmol/liter during G and fell to 3.4 mmol/liter (SED = 0.72,P <0.001) during I, then returned towards normal postinfusion. Insulin levels increased during G and I (P < 0.01) with no difference (P > 0.05) between G and I during preinfusion (163 ± 7.6 pmol/liter) or infusion (259 vs 264 ± 16.5 pmol/liter) periods. There were no differences (P > 0.05) in GH secretory characteristics, mean IGF-1, or haematocrit between G and I. However, there were significant effects of infusion within the treatments. Mean GH declined (P < 0.05) from 1.8 ng/ml (both treatments) preinfusion to 1.13 and 1.31 ng/ml during G and I infusion, respectively. GH pulse amplitude was lower during I infusion (5.6 ng/ml vs 8.2 ng/ml preinfusion,P < 0.05, SED = 1.0) and the change in amplitude from preinfusion to infusion differed (P > 0.05) with an increase in G and a decrease in I (+0.6 and −2.6, SED = 1.1). IGF-1 levels were stable and averaged 555 and 520 ng/ml (SED = 34.9) for G and I, respectively. Haematocrit declined from 34.3 ± 1.85% over the first 4 hr of sampling to 25.7 ± 0.97% for the remainder of the sampling period. The finding that there were no major alterations in GH secretory patterns during 12 hr of hypoglycemia and hyperglycemia suggests that GH secretion in the male red deer is relatively insensitive to short-term changes in metabolic state.     

Synergistic insulinotropic action of succinate, acetate, and glucose esters in islets from normal and diabetic rats

Suuccinic acid esters are currently under investigation as possible insulinotropic tools in the treatment of noninsulin-dependent diabetes mellitus. The present article introduces three novel nutrient esters and aims mainly to explore, in both normal and GK rats, the secretory response to such esters when tested alone or in combination. It documents that in pancreatic islets from normal rats, methyl acetate (10 mM), which fails to augment basal insulin output, potentiates the secretory response to succinate dimethyl ester (also 10 mM). It also reveals that α-d-glucose pentaacetate (αGPA) (1.7 mM) stimulates insulin release in the absence of any other exogenous nutrient and even more so in the presence of succinate methyl ester. Moreover, the methyl esters of succinic acid (10 mM), when used together with either methyl acetate or αGPA, provoked insulin secretion in islets from diabetic GK rats incubated in the absence ofd-glucose, although no significant secretory response of such islets could be detected when each of these agents was tested separately. These findings thus draw attention to the insulinotropic potential in type 2 diabetes of selected combinations of nutrient esters, including ad-glucose ester presumably able to enter into islet cells without requiring the intervention of a hexose carrier.     

Predictors associated with treatment initiation and switch in a real‐world chronic hepatitis B population from five European countries

In Europe, healthcare systems differ between countries and different factors may influence Chronic hepatitis B (CHB) treatment choices in different counties. This analysis from a prospective, longitudinal, non‐interventional study in five EU countries aimed to explore determinants associated with treatment initiation or switch in patients with CHB. A total of 1267 adult patients with compensated CHB in Germany, France, Poland, Romania and Turkey were prospectively followed for up to 2 years (March 2008–December 2010). Determinants of treatment initiation or switch were analysed using multivariate Cox proportional hazards regression. Median time since CHB diagnosis was 2.6 (0–37.7) years. Among 646 treatment‐naïve patients, the probability of treatment initiation during follow‐up was higher: in Germany (P = 0.0006), Poland (P < 0.0001) and Romania (P = 0.0004) compared with Turkey; in patients with alanine transaminase (ALT) 1–2 × upper limit of normal (ULN) (P = 0.0580) or >2 × ULN (P = 0.0523) compared with ALT ≤1 × ULN; and in patients with hepatitis B virus (HBV) DNA ≥2000 IU/mL (P < 0.0001) compared with HBV DNA <2000 IU/mL or undetectable. Among 567 treated patients, 87 switched treatment during follow‐up. The probability of treatment switch was higher: in France (P = 0.0029), Germany (P = 0.0078) and Poland (P = 0.0329) compared with Turkey; and in patients with HBV DNA <2000 (P < 0.0001) or ≥2000 IU/mL (P < 0.0001), compared with undetectable. Viral load and ALT level were identified as the major drivers of treatment initiation. HBV DNA level was also a significant determinant of treatment switch. Results were statistically different across EU countries.     

Evaluation of the moisturizer Pédimed(®) in the foot care of diabetic patients

Aim

Xerosis is one of the most common abnormalities observed in the diabetic foot, promoting ulceration through the development of fissures and hyperkeratosis. Its treatment is therefore paramount and must be implemented early on. The objective of this study was to assess the moisturizing properties of Pédimed^® cream in the treatment of foot xerosis in diabetic patients.

Methods

In this randomized double-blind study, Pédimed^® and its placebo were randomly allocated to the right/left foot of each patient (one active/one control side). Products were applied twice daily for 4 weeks. Xerosis was assessed using the clinical Xerosis Assessment Scale (XAS), corneometry (skin hydration measurement) and D-Squame^® (scale sample analysis) after 14 (D14) and 28 (D28) days of treatment.

Results

Twenty-four men and 30 women, aged 57.0 ± 12.7 years, with type 1 or type 2 diabetes and moderate-to-severe foot xerosis were included. A dramatic decrease in XAS score that was more marked with Pédimed^® than with placebo was observed from D14 (38.1% vs 20.9%, P < 0.0001), reaching 61.9% vs 34.9% at D28 (P < 0.0001). The number of feet with fissures was greatly reduced with Pédimed^® compared with placebo at both D14 (11.1% vs 22.2%, P = 0.031) and D28 (5.6% vs 18.5%, P = 0.039). Skin hydration increased by 48.9% with Pédimed^® vs 31.7% with placebo at D14 (P = 0.0002), reaching 57.3% vs 36.5% at D28 (P < 0.0001). All D-Squame^® parameters showed greater improvement with Pédimed^®. Product tolerability was excellent.

Conclusion

Validated clinical and paraclinical tools demonstrated the efficacy of Pédimed^® in improving xerosis and reducing fissures of the feet in diabetic patients.     

Melatonin reduces hepatic mitochondrial dysfunction in diabetic obese rats

Hepatic mitochondrial dysfunction is thought to play a role in the development of liver steatosis and insulin resistance, which are both common characteristics of obesity and type 2 diabetes mellitus (T2DM). It was hypothesized that the antioxidant properties of melatonin could potentially improve the impaired functions of hepatic mitochondria in diabetic obese animals. Male Zucker diabetic fatty (ZDF) rats and lean littermates (ZL) were given either melatonin (10 mg/kg BW/day) orally for 6 wk (M‐ZDF and M‐ZL) or vehicle as control groups (C‐ZDF and C‐ZL). Hepatic function was evaluated by measurement of serum alanine transaminase and aspartate transaminase levels, liver histopathology and electron microscopy, and hepatic mitochondrial functions. Several impaired functions of hepatic mitochondria were observed in C‐ZDF in comparison with C‐ZL rats. Melatonin treatment to ZDF rats decreases serum levels of ALT (P < 0.001), alleviates liver steatosis and vacuolation, and also mitigates diabetic‐induced mitochondrial abnormalities, glycogen, and lipid accumulation. Melatonin improves mitochondrial dysfunction in M‐ZDF rats by increasing activities of mitochondrial citrate synthase (P < 0.001) and complex IV of electron transfer chain (P < 0.05) and enhances state 3 respiration (P < 0.001), respiratory control index (RCR) (P < 0.01), and phosphorylation coefficient (ADP/O ratio) (P < 0.05). Also melatonin augments ATP production (P < 0.05) and diminishes uncoupling protein 2 levels (P < 0.001). These results demonstrate that chronic oral melatonin reduces liver steatosis and mitochondria dysfunction in ZDF rats. Therefore, it may be beneficial in the treatment of diabesity.     

Expression and significance of nerve growth factor receptor p75 in rats’ cathartic colonic wall

OBJECTIVE: To investigate the expression of nerve growth factor receptor p75 in a normal and cathartic colon and its significance in the formation of the cathartic colon in rats. METHODS: Sixty Sprague–Dawley rats were equally divided into normal control group, rhubarb group and phenolphthalein group. A model of the cathartic colon was constructed by gastric infusion with rhubarb or phenolphthalein in rats. The first dose of rhubarb and phenolphthalein was both 200 mg/kg/d and was increased by 200 mg/kg/d with each passing day. The last dose of rhubarb and phenolphthalein was 3200 mg/kg/d and 4200 mg/kg/d, respectively. The transit function of colon was measured by the Chinese ink expulsion test; the p75 in colon wall was determined by the immunohistochemical method. RESULTS: The transit speed was much slower in the cathartic colon group than that in the control group. The imprinted Chinese ink length and the ratio of imprinted length/total colon length in the rhubarb‐induced cathartic colon was significantly shorter than that of the control group (77.38 ± 8.42 vs 94.25 ± 7.07 cm, P < 0.01). Those in the phenolphthalein‐induced group (83.38 ± 9.75 cm) were also significantly shorter than those of the control group but to a lesser degree (P < 0.05). p75 was abundantly expressed in the submucosal nerve plexus and weakly expressed in the myenteric plexus. The expression of p75 was much higher in the rhubarb‐induced group. The expression was strongly positive in the submucosal nerve plexus, significantly higher than that in the controls (P < 0.01). In the myenteric plexus, p75 was also highly expressed (P < 0.05). In the case of the phenolphthalein‐induced group, the expression of p75 was positive in the submucosal nerve plexus but was positive in the myenteric plexus of three rats only. The remaining rats were negative or weakly positive. This was not significantly different from that of the control group. CONCLUSIONS: The abnormal expression of p75 in cathartic colon probably has some effect on the degeneration or apoptosis of neuronal cells in the enteric nerve plexus, with a subsequent pathological change of the enteric nervous system, and thus leads to abnormalities in colonic dynamics. The kind of lesion is probably associated with long‐term use of irritative cathartics.     

Adenosine 5'-triphosphate (ATP) receptors induce intracellular calcium changes in mouse leydig cells

Cytoplasmic calcium ([Ca²⁺]_i) changes evoked by adenosine 5¹-triphosphate (ATP) were recorded in cultured individual Leydig cells within 10–18 h after cell dispersion. [Ca²⁺]_i was monitored using Fura-2AM loaded cells with a digital ratio imaging system. Five micromolars ATP induced biphasic [Ca²⁺]_i responses in most cells (94%,n=100), characterized by a fast increase from a basal level (126±5 nMSE,n=60 cells) to a peak (5–7 times above basal levels) within seconds, followed by a slow decrease toward a plateau level (2–3 times above basal) within 5 min. The peak phase of the [Ca²⁺]_i response increased with ATP concentrations (1–100 μM ATP) in a dose-dependent manner with an IC₅₀ of 5.9±1.2 μM, and it desensitized in a reversible manner with repeated application of 5 μM ATP at <5-min intervals. The [Ca²⁺]_i peak response was dependent on Ca²⁺ release from an intracellular pool, whereas the plateau phase was dependent on extracellular [Ca²⁺]. ATP did not appear to induce formation of nonspecific membrane pores, since stimulation for 10 min with ATP (10–100 μM) in the presence of extracellular Lucifer yellow (LY) (5 mg/mL) did not result in dye loading of the cells. [Ca²⁺]_i transients were elicited by other adenosine nucleotides with an order of potencies (ATP>Adenosine diphosphate [ADP]>Adenosine> Adenosine monophosphate [AMP]) that was compatible with the expression of P₂ receptors. [Ca²⁺]_i responses were suppressed by the purinergic P₂ receptor antagonist, suramin. These results provide functional evidence for the expression of purinergic P₂ receptors in Leydig cells.     

CD49d (ITGA4) expression is a predictor of time to first treatment in patients with chronic lymphocytic leukaemia and mutated IGHV status

We investigated CD49d (also termed ITGA4) expression and its biological and clinical correlations in 415 patients with chronic lymphocytic leukaemia. CD49d expression was stable over the course of the disease. A high expression of CD49d (>30%) was found in 142/415 (34%) patients and was associated with progressive disease (advanced clinical stage, high serum lactate dehydrogenase or β₂‐microglobulin levels; all p < 0·05) and aggressive disease biology (increased ZAP70 or CD38, unmutated IGHV, trisomy 12, mutations of NOTCH1 and SF3B1; all P < 0·05). A higher CD49d expression was also associated with a lower blood lymphocyte count and a higher number of lymphoid areas involved by the disease. Patients with high CD49d expression were treated more frequently (55% vs. 27%; P < 0·001) and earlier (median time to treatment [TTT] 65·4 months vs. not reached; P < 0·001) than those with low CD49d expression. However, no significant differences in response rates were observed. In the subgroup of patients with mutated IGHV, high CD49d expression was predictive of a shorter TTT while other markers, such as ZAP70 and CD38, were not. In conclusion, in this study CD49d expression correlated with high‐risk CLL biomarkers and proved to be useful for separating patients with mutated IGHV into two different prognostic groups.     

Melatonin increases brown adipose tissue mass and function in Zücker diabetic fatty rats: implications for obesity control

Melatonin limits obesity in rodents without affecting food intake and activity, suggesting a thermogenic effect. Previously we demonstrated that melatonin browns subcutaneous fat in Zücker diabetic fatty (ZDF) rats. Other works pointed to melatonin as a signal that increases brown adipose tissue (BAT) mass and function in rodents. However, direct proof of thermogenic properties (uncoupled mitochondria) of the newly recruited BAT in response to melatonin is still lacking. Therefore, in this work, we investigated if melatonin recruits thermogenic BAT in ZDF rats. Zücker lean (ZL) and ZDF animals were subdivided into two groups, control (C) and treated with oral melatonin (M) for 6 weeks. Mitochondrial mass, activity of citrate synthase (CS), and respiratory chain complexes I and IV were lower in C‐ZDF than in C‐ZL animals (P < .001). Melatonin treatment increased BAT weight in ZDF rats (P < .001). Also, it rose mitochondrial mass (P < .01) and activities of CS and complexes I and IV (P < .001) in both, ZDF and ZL rats. Uncoupling protein 1 (UCP1) mRNA and protein were 50% lower in BAT from obese rats. Also, guanosine diphosphate (GDP) binding was lower in ZDF than in lean rats (P < .01). Melatonin treatment of obese rats restored the expression of UCP1 and GDP binding to levels of lean rats and sensitized the thermogenic response to cold exposure. These data demonstrated that melatonin recruits thermogenic BAT in ZDF rats. This may contribute to melatonin's control of body weight and its metabolic benefits.     

Topographic Differences in Cell Populations and Insulin Secretion in the Endocrine Pancreas of the ToadBufo arenarum

We analyzed the endocrine cell topography within the amphibian pancreas and the relationship of this distribution to lobular variation in insulin content and secretion. Pancreases from adult male toadBufo arenarumwere separated into their five lobes: free, gastric, hepatic, duodenal, and jejunal. Pieces of each lobe were incubated with glucose, arginine, and K⁺and the insulin concentration in the medium was measured by radioimmunoassay. In the presence of 2 or 8 mMglucose, 10 mMarginine, and 10 mMK⁺the free lobe released a significantly greater amount of insulin than the other lobes, while the output of the gastric lobe was greater than that of the duodenal, hepatic, and jejunal. At 8 mMglucose, every pancreatic lobe released a significantly higher amount of insulin than at 2 mM. The insulin content of the free lobe was significantly higher than that of the others, whereas this parameter was comparable among the latter. These pancreases contained islets of variable size and irregular shape. B and non-B cells, detected by immunoperoxidase staining, were located at the central and peripheral zones of the islets, respectively. A large number of non-B cells were also scattered over the exocrine component. Morphometrical analyses revealed the following sequence of endocrine cell percentage: free lobe > gastric lobe = duodenal lobe > jejunal lobe = hepatic lobe. Some 48% of the endocrine cells were present in the islets, while the remaining 52% were found throughout the exocrine pancreas. In the free lobe, more endocrine cells were located within the islets (65%) than outside and in the gastric lobe the proportion was almost equal (48% within, 52% outside), but in the hepatic, duodenal, and jejunal lobes the majority lay outside the islets (61, 63, and 70% extrainsular, respectively). The area covered by B and D cells was far larger within the islets than outside, with the relative magnitude of this difference being free lobe > gastric lobe > duodenal lobe > hepatic lobe = jejunal lobe. In the free lobe, this relative distribution was more skewed than in the remaining lobes. PP and A cells occupied a more extensive area outside the islets than inside in every lobe. There were no significant differences among the extrainsular areas occupied by each type of endocrine cell within a given pancreatic lobe. These results constitute the first demonstration of the heterogeneity in morphology, insulin content, and secretory function among the pancreatic lobes inB. arenarum.The data further suggest that the nonuniform secretory capacities of amphibian pancreatic lobes reflect localized differences in their insulin content, which heterogeneity in turn stems from the dissimilar distribution and organization of their constituent endocrine-cell populations.     

Association of socioeconomic deprivation with sleep health in patients with type 2 diabetes

Aims

To investigate the association between socioeconomic deprivation and indicators of sleep health among patients with type 2 diabetes mellitus (T2DM), and additionally, to examine whether socioeconomic deprivation is associated with higher glycated haemoglobin (HbA1c) levels in these patients.

Materials and Methods

We analysed data from the UK Biobank, consisting of 17 206 participants with T2DM, to explore the relationship between socioeconomic deprivation, self-reported indicators of sleep health, and HbA1c levels. Socioeconomic deprivation was assessed using the Townsend deprivation index. Participants were divided into two groups: low socioeconomic deprivation (n = 8604; reference group) and high socioeconomic deprivation (n = 8602). Logistic regression models were employed, adjusting for covariates such as body mass index (BMI), age, and biological sex.

Results

Patients with high socioeconomic deprivation had higher odds of reporting usual difficulties falling asleep or sleeping through the night (adjusted odds ratio 1.20, 95% confidence interval [CI] 1.12, 1.28), and they were more likely to use at least one hypnotic medication (adjusted odds ratio 1.41, 95% CI 1.09, 1.84). They also had higher odds of reporting snoring and difficulties staying awake during the daytime (adjusted odds ratio 1.09, 95% CI 1.01, 1.18), as well as experiencing short sleep duration (defined as <6 hours of sleep per day; adjusted odds ratio 1.69, 95% CI 1.50, 1.91). Moreover, patients with high socioeconomic deprivation had increased odds of experiencing comorbid sleep problems (P ≤ 0.001). Finally, high socioeconomic deprivation was associated with a 0.1% higher HbA1c level (P < 0.001). Controlling for indicators of poor sleep health did not alter the strength of this association.

Conclusions

Socioeconomic deprivation may represent a risk factor for poor sleep health in patients with T2DM.     

Early development of de novo hepatocellular carcinoma after direct‐acting agent therapy: Comparison with pegylated interferon‐based therapy in chronic hepatitis C patients

Patients with chronic hepatitis C who achieve a sustained viral response after pegylated interferon therapy have a reduced risk of hepatocellular carcinoma, but the risk after treatment with direct‐acting antivirals is unclear. We compared the rates of early development of hepatocellular carcinoma after direct‐acting antivirals and after pegylated interferon therapy. We retrospectively analysed 785 patients with chronic hepatitis C who had no history of hepatocellular carcinoma (211 treated with pegylated interferon, 574 with direct‐acting antivirals) and were followed up for at least 24 weeks after antiviral treatment. De novo hepatocellular carcinoma developed in 6 of 574 patients receiving direct‐acting antivirals and in 1 of 211 patients receiving pegylated interferon. The cumulative incidence of early hepatocellular carcinoma development did not differ between the treatment groups either for the whole cohort (1.05% vs 0.47%, P = .298) or for those patients with Child‐Pugh Class A cirrhosis (3.73% vs 2.94%, P = .827). Multivariate analysis indicated that alpha‐fetoprotein level >9.5 ng/mL at the time of end‐of‐treatment response was the only independent risk factor for early development of hepatocellular carcinoma in all patients (P < .0001, hazard ratio 176.174, 95% confidence interval 10.768‐2882.473) and in patients treated with direct‐acting agents (P < .0001, hazard ratio 128.402, 95% confidence interval 8.417‐1958.680). In conclusion, the rate of early development of hepatocellular carcinoma did not differ between patients treated with pegylated interferon and those treated with direct‐acting antivirals and was associated with the serum alpha‐fetoprotein level at the time of end‐of‐treatment response.