Change in body weight after hormone replacement therapy in postmenopausal women is dependent on basal circulating leptin

Objective: To address the effect of leptin in the modulation of change in body weight after hormone replacement therapy (HRT), we prospectively examined the responses of body weight and serum leptin after estrogen–progestin replacement in postmenopausal women. Patients: Subjects consisted of 63 postmenopausal women aged 54–82 years on HRT for osteoporosis. Design: Thirty three of the subjects received 0.3 mg of conjugated equine estrogen (CEE) (group 1) while 30 were on 0.625 mg of CEE daily (group 2). All subjects also took 5 mg of medrogestone acetate and 750 mg elemental calcium supplement daily. Measurements: Fasting serum leptin was measured by RIA at baseline, 1 and 3 months after treatment. Data were expressed as mean±S.E.M. Results: Serum leptin was highly related to body weight both at baseline (r=0.40, P<0.001) and after 3 months of HRT (r=0.42, P<0.001). When divided the subjects into three equal groups according to baseline leptin levels, it was found that serum leptin significantly decreased in subjects with high baseline leptin at 3 months (−9.4±5.7%, P<0.05) while it increased in subjects whose baseline leptin levels were in the lowest tertile at 1 month (33.2±8.3%, P<0.001) and 3 month (27.8±8.3%, P<0.01). In regards to body weight, those with leptin in the highest tertile demonstrated a reduction of body weight at 3 (−1.9±0.6%, P<0.05) and 12 months (−3.2±0.5%, P<0.05) after HRT while those whose serum leptin levels were in the lowest and middle tertiles did not demonstrate change in body weight. By repeated measured analysis of variance, it was found that the decrease in body weight in subjects with high serum leptin was independent of the doses of estrogen. Conclusion: Postmenopausal hormone replacement does not cause weight gain. However, it results in a small reduction in body weight particularly in subjects with higher basal leptin concentrations.     

Regulation of hepatic blood flow in patients with liver cirrhosis and after liver transplantation

We studied liver blood flow at rest and its regulatory changes after exercise and food intake in ten patients with advanced liver cirrhosis and in 14 patients more than 10 months after orthotopic liver transplantation. The results were compared with those obtained in ten healthy volunteers. Sorbitol steady state infusion was employed to measure functional liver blood flow (FLBF). Thirty minutes of half-maximal muscular work, performed on a supine position ergometer and consumption of a standard meal were used as stimuli to study regulatory changes in hepatic perfusion. Results: FLBF at rest was reduced in end stage cirrhosis (mean 1257±105 ml/min in cirrhosis vs. 1707±76 ml/min in controls; P<0.01). After liver transplantation FLBF at rest was normalized (mean 1922±169 ml/min) in patients with stable graft function. Muscular exercise led to a reduction in FLBF, which in the transplanted patients was the same range as in normal controls (−26.7±3.7%; −24.7±0.7, respectively), but was reduced in cirrhosis (−19.1±2.1%; P<0.05). After ingestion of a standard meal FLBF increased substantially in normal controls (+40.2±2.3%), while in patients with cirrhosis this increase was rather small (+10.1±1.9%; P<0.001). After transplantation the food-induced increase in FLBF(+20.5±3.6%) was larger than in cirrhosis (P<0.05) but remained smaller than in the controls (P<0.01). We conclude that in cirrhosis FLBF is reduced and adaptive changes after exercise or food intake are impaired. After transplantation FLBF is normalized, but blood flow regulation, especially after food intake remains abnormal.     

Relaxation responses of aortic rings from salt-loaded high calcium fed rats to potassium chloride, calcium chloride and magnesium sulphate

The relaxation responses of aortic rings of rats fed either normal rat feed, 8% salt diet, 8% salt+2.5% Ca diet or 2.5% Ca diet for 6–8 weeks has been investigated. The mean arterial pressure of salt loaded rats (148.63±8.54 mmHg) was higher (P<0.05) than those of control (108.36±7.81 mmHg), salt-loaded Ca-fed (101.62±7.38) and Ca fed (98.54±8.72) rats. The maximum KCl-induced relaxation of the aortic rings was least (55.5±3.5%, P<0.05) in salt loaded rats when compared to the maximum KCl-induced relaxation of control (70.76±3.65%), salt+Ca fed (73.12±3.46%) and Ca fed (79.3±3.68%) rats. Salt loading attenuated the maximum relaxation to CaCl₂ (P<0.05) when compared to the maximum relaxation responses of control rats, salt+Ca fed and Ca fed rats. The Mg-induced relaxation was lower (P<0.05) in salt loaded rats than any other group. Increasing the extracellular fluid calcium concentration to 2.61 and 5.1 mmol l⁻¹ significantly (P<0.05) increased the relaxation responses to MgSO₄ in aortic rings from all the groups. The result of this study indicates that salt-loading caused significant increase in the blood pressure of the rats and also reduced the relaxation responses of the aortic rings to KCl, MgSO₄ and CaCl₂ which suggest altered Na⁺,K⁺-ATPase activity and resistance of the vascular smooth muscle membrane to calcium-induced membrane stabilization. These defects were reversed by dietary calcium supplement.     

Bone turnover and its relationship with bone mineral density in pre- and postmenopausal women with or without fractures

Objective: This work was carried out in order to investigate possible relationships between bone turnover rate, as evaluated by bone biomarkers and skeletal mass, as evaluated by bone mineral density (BMD). Method: Fifty-eight normal women and 30 female patients with osteoporotic fractures were enrolled. Three groups were defined: (1) fertile subjects (n=24), mean age 33.7±8.1 years; (2) postmenopausal women (n=32, including 11 patients with fractures) whose BMD values, in terms of T score, were less than −2.5 S.D. below the young adult mean obtained in our laboratory (mean age 61.7±7.9 years; and years since menopause (ysm), 12.6±8.3); (3) postmenopausal women (n=32, including 19 patients with fractures) whose BMD values in terms of T score, were below −2.5 S.D. (mean age 62.9±8.6 years; and ysm 15.9±9.0). Groups II and III characterised, by inclusion criteria, by significant different mean BMD values, were similar as far as chronological and menopausal age were considered. Metabolic tests included a short urine collection to determine calcium, hydroxyproline, cross-linked N-telopeptides of type I collagen (NTx) and creatinine (Cr); half-way through this collection, a blood sample was taken for the measurement of total alkaline phosphatase activity (ALP) and tartrate-resistant acid phosphatase activity (TRAP). BMD at lumbar spine was evaluated. Results: There were significant differences amongst the three groups in mean ALP (P<0.001, by analysis of variance) TRAP (P<0.006) and NTx/Cr (P<0.001) values, but not as far as mean values of calcium/Cr or hydroxyproline/Cr ratios were concerned. Considering the group as a whole, there were significant inverse correlations between NTx/Cr, ALP, TRAP and BMD controlling for both age (r=−0.392, P<0.001; r=−0.447, P<0.001 and r=−0.327, P<0.002, respectively) and ysm (r=−0.374, P<0.001; r=−0.474, P<0.001 and r=−0.333, P<0.002). Conclusions: Our results indicate, that, even after controlling for both ageing and oestrogen status, there is an inverse relationship between bone mass (that at a given time represents the balance of all previous metabolic events) and a biochemical marker (which reflects bone turnover at the time of examination). These findings are in line with the belief that increased bone turnover should be regarded as a risk factor for osteoporosis. Furthermore, our results indicate that, unless there is no increase of hepatic isozyme, total ALP still maintains a possible role as a first analysis to evaluate bone turnover before requesting markers with greater specificity, sensitivity but also more expensive and whose analysis is sometimes time-consuming.     

Effects of menopause and hormone replacement therapy on plasma lipids, lipoproteins and LDL-receptor activity

A cross-sectional study of ninety six women was conducted to examine the effect of menopause and hormone replacement therapy (HRT) on plasma lipids, lipoproteins and oxidation of low density lipoproteins. The sample consisted of 26 premenopausal women, 26 postmenopausal women taking no replacement hormones and 43 postmenopausal women on hormone replacement therapy. Postmenopausal women not taking replacement hormones had significantly higher plasma cholesterol, low density lipoprotein (LDL) cholesterol and lipoprotein[a] (Lp[a]) levels compared to premenopausal women or postmenopausal women on HRT [6.00±0.15, 5.36±0.17 (P<0.01), 5.63±0.13 (P<0.05) mmol/l, respectively for total cholesterol; 4.13±0.15, 3.64±0.15 (P<0.05), 3.82±0.12 (P<0.05) mmol/l, respectively for LDL-cholesterol; 48.19±9.90, 26.59±5.53 (P<0.03), 25.12±4.62 (P<0.03) mg/dl, respectively for Lp[a]]. The differences in LDL cholesterol concentrations were inversely related to changes in LDL receptor activity (r=−0.27, P<0.01). HRT use was found to be associated with a significantly smaller LDL particle size. Plasma triglyceride was significantly higher in women on HRT (1.16±0.07 mmol/l) than in the premenopausal group (0.96±0.07) or postmenopausal group not using HRT (0.87±0.06). There were no differences in LDL oxidation between the groups when LDL was oxidised in the presence of copper. Nor was there any difference in the uptake of copper-oxidised or macrophage-modified LDL into J774 macrophages. These results confirm the effect of menopause and exogenous hormones on plasma lipids and lipoproteins, and suggest that HRT modifies the activity of the LDL receptor. Hormone replacement did not appear to protect LDL from oxidation.     

Progestins used in hormonal replacement therapy display different effects in coronary arteries from New Zealand white rabbits

Objectives: The aim of this study was in an animal model to assess the vascular effects of different progestins commonly used in hormonal replacement treatment. Methods: Fifty-six non-atherosclerotic, ovariectomized New Zealand white rabbits were randomized into seven groups: (1) medroxyprogesterone acetate (MPA), (2) norethisterone acetate (NETA), (3) conjugated equine estrogens (CEE), (4) 17-β-estradiol (E2), (5) MPA+CEE, (6) NETA+E2, (7) or placebo (n=8) and given hormonal treatment through the diet for 4 weeks. Ring segments from the left proximal coronary artery and from the distal part of the left anterior descending coronary artery were microdissected and mounted for isometric tension recordings in a myograph. The vasoconstrictory responses induced by potassium, endothelin-1, calcium and N_w-nitro- -arginine methyl ester, and the vasodilatory response induced by acetylcholine and sodiumnitroprusside were investigated. The maximum contraction/relaxation (E_max) and the concentration required to induce half the maximum response (EC₅₀) were determined. EC₅₀ values were expressed as the negative logarithm to the molar concentration, pD₂=−log EC₅₀. Results: Treatment with MPA alone caused when compared to treatment with NETA an increase in tension development in the distal coronary artery after the addition of potassium (6.36±0.36 versus 4.31±0.42 P<0.005) (single dose response, mN/mm, mean±S.E.M.) and endothelin-1 (9.41±0.82 versus 6.43±0.73 P<0.05) (E_max, mN/mm, mean±S.E.M.). Treatment with MPA compared to placebo caused an endothelin-1 induced increase of E_max in the distal coronary artery (9.21±0.87 versus 6.51± 0.65 P<0.05) and a calcium induced increase of pD₂ in both coronary arteries (2.98±0.19 versus 2.42±0.12 P<0.05, proximal coronary artery) (3.26±0.09 versus 2.9±0.1 P<0.05, distal coronary artery) (pD₂, mean±S.E.M.). Treatment with NETA compared to placebo in the proximal coronary artery, after the addition of sodiumnitroprusside caused a decrease of pD₂ (5.33±0.19 versus 5.94±0.13 P<0.05). Treatment with E2 compared to treatment with CEE in the proximal coronary artery caused a decrease of pD₂ after the addition of sodiumnitroprusside (5.00±0.16 versus 5.77±0.28 P<0.05). No significant differences were found between MPA+CEE and NETA+E2. Conclusion: Treatment with MPA alone seems to enhance the contractile response to potassium and endothelin-1 in the distal coronary artery compared to NETA, indicating that different progestins used in hormonal replacement treatment may display different effects on contractile functions of coronary arteries.     

Strain differences in baroceptor reflex in adult wistar kyoto rats

OBJECTIVES

A subset of normotensive Sprague–Dawley rats show lower baroreflex sensitivity; however, no previous study investigated whether there are differences in baroreflex sensitivity within this subset. Our study compared baroreflex sensitivity among conscious rats of this specific subtype.

METHODS

Male Wistar Kyoto (WKY) rats (16 weeks old) were studied. Cannulas were inserted into the abdominal aortic artery through the right femoral artery to measure mean arterial pressure (MAP) and heart rate (HR). Baroreflex gain was calculated as the ratio between change in HR and MAP variation (ΔHR/ΔMAP) in response to a depressor dose of sodium nitroprusside (SNP, 50 μg/kg, i.v.) and a pressor dose of phenylephrine (PE, 8 μg/kg, i.v.). Rats were divided into four groups: 1) low bradycardic baroreflex (LB), baroreflex gain (BG) between -1 and -2 bpm/mmHg tested with PE; 2) high bradycardic baroreflex (HB), BG < -2 bpm/mmHg tested with PE; 3) low tachycardic baroreflex (LT), BG between -1 and -2 bpm/mmHg tested with SNP and; 4) high tachycardic baroreflex (HT), BG < -2 bpm/mmHg tested with SNP. Significant differences were considered for p < 0.05.

RESULTS

Approximately 37% of the rats showed a reduced bradycardic peak, bradycardic reflex and decreased bradycardic gain of baroreflex while roughly 23% had a decreased basal HR, tachycardic peak, tachycardic reflex and reduced sympathetic baroreflex gain. No significant alterations were noted with regard to basal MAP.

CONCLUSION

There is variability regarding baroreflex sensitivity among WKY rats from the same laboratory.     

A comparison of the central effects of different progestins used in hormone replacement therapy

Objective: To evaluate the central effect exerted by different progestins used for hormone replacement therapy. Methods: Randomised, placebo-controlled study. One hundred-twenty postmenopausal women on continuous hormonal replacement therapy with transdermal estradiol (50 μg per day) associated, for 10 days every 28 days, with four different progestins: dydrogesterone (DYD; 10 mg per day; n=20), medroxyprogesterone acetete (MPA; 10 mg per day; n=20), nomegestrol acetate (NMG; 5 mg per day; n=20) or norethisterone acetate (NETA; 10 mg per day; n=20). Other 40 women, 10 for each treatment group, were used as controls and were monitored for a single cycle of 28 days during the administration of transdermal estradiol plus placebo. Morning basal body temperature (BBT) was monitored for 28 days. Anxiety, by the state-trait anxiety inventory, and depression, by the self-evaluation depression scale of Zung, were evaluated just prior to and in the last 2 days of the 10-day progestins adjunct. Results: All progestins except DYD increased (P<0.0001) BBT by 0.3–0.5 °C. Anxiety was decreased by DYD (−2.3+1.1; P<0.01) and MPA (−1.5+0.5; P<0.01), but not by NMG or NETA. Depression did not significantly increase during progestins and actually decreased during MPA (−3.0+0.7; P<0.01). Only the effect of DYD on anxiety and that of MPA on depression were significant versus the control group (P<0.05). Conclusions: Different progestins exert different central effects. DYD has the peculiarity of not increasing BBT and of decreasing anxiety, which is also decreased by MPA. Depression is not negatively affected by the tested progestins and it may be ameliorated by MPA. The present data may help to individualise the progestin choice of hormone replacement therapy.     

Effect of estrogen replacement therapy on speed of sound at multiple skeletal sites

Objectives: To evaluate the effect of estrogen replacement therapy (ERT) on postmenopausal bone loss by multi-site ultrasound measurement. Methods: A cross-sectional comparison of postmenopausal women, ERT users and non-users. The two study groups were enrolled for the reference database collection for the Sunlight Omnisense™ (Omnisense) and were matched by years since menopause. Speed of sound (SOS) was measured at the distal radius (RAD), mid-shaft tibia (TIB), fifth metatarsus (MTR) and proximal phalanx (PLX). Results: 143 ERT users for 5.2±3.6 years were compared with 139 ERT non-users (age: 57.0±5.3 and 57.5±5.5, respectively). Both groups were 7.1±5.0 years since menopause. SOS, expressed in T-score units, was higher at the RAD in ERT users as compared to ERT non-users (−0.55±1.30 and −1.36±1.60, respectively, P<0.0001), and at the TIB (−0.73±1.34 and −1.28±1.45, respectively, P=0.003). Same trend was observed at the MTR and PLX, but not statistically significant because of fewer observations. In early post menopause period, the ERT-non users RAD data shows an annual SOS decrease of 0.17 versus annual increase of 0.12 T-score units (P=0.037). Similar effect is observed at the TIB, though not statistically significant (non-users decrease of 0.20 vs. users increase of 0.08 T-score units/year, P=0.086). Conclusions: SOS measurements by Omnisense at multiple skeletal sites support the ERT protective effect on bone.     

Prophylaxis of osteoporosis with calcium, estrogens and/or eelcatonin: comparative longitudinal study of bone mass

Objective: To evaluate three different therapeutic regimens for the prevention of osteoporosis in natural and surgical postmenopausal women who had been found to have rapid bone loss in analytical studies. Methods: A total of 104 naturally or surgically postmenopausal women were studied, and subsequently followed-up during 1 year for avoidance of the influence of seasonal variation on bone mass, a factor overlooked in several studies. They were randomized into four groups of 26 patients each: the untreated control group (mean age 50 ± 5 years); the hormonal replacement treatment (HRT) group (mean age 48 ± 6 years), which was treated for 24 days each month with transdermal 17β-estradiol, 50 mg/day, together with medroxiprogesterone, 10 mg during 12 days; the calcium group (mean age 50 ± 4 years), which was treated with elemental calcium, 1 g/day; and the calcitonin group (mean age 50 ± 5 years), which was treated for 10 days each month with eel calcitonin, 40 IU/day and with elemental calcium, 500 mg/day. Full-body bone densitometry, for measuring total body bone mineral content (TBBMC), was carried out in all the women at baseline and 1 year. TBBMC was corrected for body weight by dividing its value by body weight (TBBMC/W). Results: After 1 year TBBMC/W was lower in every group: −2.14% (P < 0.001) in the control group; −0.14% (P = NS) in the HRT group (P < 0.05 vs. controls); −0.18% (P = NS) in the calcium group (P < 0.05 vs. controls); and −0.06% (P = NS) in the calcitonin group (P < 0.01 vs. controls; P < 0.05 vs. calcium and HRT). Conclusions: These findings show that all three treatments are effective in the prevention of postmenopausal loss of bone mass.     

Value of C-reactive protein levels and IL-6 in predicting events levels in women at increased cardiovascular risk

Background: Elevated C-reactive protein (CRP) levels due to of heightened vascular inflammatory state in vascular conditions are often associated with elevated interleukin-6 (IL-6) levels since during inflammation CRP production in the liver is induced by IL-6. It has been suggested that CRP may be a predictors of unfavourable outcome in postmenopausal women (PMW) receiving hormone replacement therapy. Because of the possible metabolic effect of hormone replacement therapy (HRT) on CRP, the relative predictive importance of CRP and IL-6 levels in PMW receiving HRT remains to be elucidated. Methods: We measured plasma levels of CRP and IL-6 levels in 346 consecutive PMW (mean age 66±9 years) with cardiovascular risk >20 in 10 years followed during a 36 month period. Women underwent measurement of inflammatory cytokines at baseline and were allocated to two groups according to the willingness to take hormone replacement therapy. All women underwent a further measurement of CRP and IL-6 at 3 and 6 months. Health status was assessed by out patient visits and hospital charts. Results: During 1 year follow up, three patient died, four had a major cardiovascular event, three had a unstable angina, two had a transient ischemic attack and two patients underwent PTCA. PMW with events had higher CRP levels compared with patients with no events (1.94±0.61 versus 1.43±0.21, P<0.05) but still within the limits of normal. Also baseline IL-6 plasma levels were significantly higher in PMW with events than in those without events (0.87±0.23 versus 0.54±0.18, P<0.05). The increase in CRP and IL-6 with HRT was significantly higher in patients with events than in those with no events (CRP: 81±12% versus 76±21%, P<0.05; IL-6 9±3% versus −14±7%, P<0.05). In a stepwise multivariate analysis, IL-6 levels resulted a stronger predictor of outcome than CRP. CRP levels were predictors of future events only after removal of IL-6 levels and presence of cardiovascular symptoms from the analysis. CRP levels were associated with an unfavourable outcome only when IL-6 levels were also elevated. The increase in CRP with HRT during follow up was not associated to an increased event rate. Conclusion: Our study showed that CRP levels are increased in PMW receiving HRT. Elevated IL-6 levels may identify those PMW at increased 1 year risk. CRP levels predict events only when they are coupled with elevated IL-6 levels.     

Bone density patterns after normal and premature menopause

Objectives: The investigation of the effect of time and type of menopause on bone mineral density (BMD) at different ages. Methods: Five hundred and fourteen women, who had never received any hormonal substitution were studied in a cross-sectional design: 177 with normal (NMP), 210 with surgical (SUMP) and 127 with premature natural (EMP) menopause. Age at menopause was 49.1±3.9, 38.3±4.7 and 38.1±4.2 years (mean±1 S.D.), respectively. BMD was measured at L2–L4 vertebrae and proximal femur by the DEXA method. Results: EMP women presented significantly lower vertebral BMD than NMP women in the 45–55-years segments (P<0.001), but did not differ from SUMP women. This group exhibited lower vertebral BMD than NMP between 45 and 50 years (P<0.001). Regarding femoral neck, EMP women exhibited lower values than SUMP in the 45–50 and 55–65 age segments (P<0.001) whereas SUMP women presented significantly higher BMD values than NMP women after 55 years of age (P<0.001). The percentages of women with vertebral BMD (T-score values) in the osteoporotic range were significantly greater in EMP compared with either NMP or SUMP groups (both P<0.001) whereas in femoral neck lower in SUMP than the other two categories. Conclusions: Women with either natural or surgical premature menopause exhibit lower BMD of trabecular bone compared with normal menopause women at the age segments 45–55 and 45–50, respectively. However, surgical menopause women exceed normal menopause women in their mixed bone BMD values after 60 years as well as premature natural menopause women at almost all age segments.     

Androgen dependence in hamsters: overdose, tolerance, and potential opioidergic mechanisms

Anabolic steroids are drugs of abuse. However, the potential for steroid reward and addiction remains largely unexplored. This study used i.c.v. testosterone self-administration and controlled infusions of testosterone or vehicle in hamsters to explore central mechanisms of androgen overdose. Forty-two hamsters used nose-pokes to self-administer 1 μg/μl testosterone i.c.v. 4 h/day in an operant chamber. During 1–56 days of androgen self-administration, 10 (24%) hamsters died. Deaths correlated with peak daily intake of testosterone. Of the hamsters that self-administered a peak intake of <20 μg/day, there was 100% survival (10/10). Survival decreased to 86% (19/22) when daily testosterone intake peaked at 20–60 μg/day. Only 30% (three of 10) survived when daily testosterone intake exceeded 60 μg/day. Deaths are not due to volume or vehicle because i.c.v. infusions of 80 μl vehicle had no effect. Testosterone overdose resembles opiate intoxication. When male hamsters received infusions of 40 μg testosterone, locomotion (25.1±18.8 grid-crossings/10 min), respiration (72.7±5.4 breaths/min) and body temperature (33.5±0.4 °C) were significantly reduced, compared with males receiving vehicle infusions (186.1±8.1 crossings/10 min, 117.6±1.0 breaths/min, 35.9±0.1 °C, P<0.05). However, males developed tolerance to continued daily testosterone infusion. After 15 days, locomotion (170.2±6.3 crossings), respiration (118.4±1.3 breaths/min), and body temperature (35.3±0.3 °C) in testosterone-infused males were equivalent to that in vehicle controls (P>0.05). The depressive effects of testosterone infusion are blocked by the opioid antagonist, naltrexone. With naltrexone pre-treatment (10 mg/kg s.c.), locomotion (183.7±1.8 crossings/10 min), respiration (116.9±0.3 breaths/min), and body temperature (36.1±0.4 °C) during testosterone infusion were equivalent to vehicle controls. Likewise, naltrexone prevents the reinforcing effects of i.c.v. testosterone self-administration. These results indicate that testosterone at high doses causes central autonomic depression, which may be a factor in deaths during self-administration. As well, the depressive effects of large quantities of testosterone may be mediated, at least in part, by an opioidergic mechanism.     

Plasma androstenedione and oestrone levels in the climacteric syndrome

Plasma androstenedione (A) and oestrone (E₁) levels were measured by radioimmunoassay in a group of 78 healthy women who had undergone a natural menopause. Of this total, 23 were symptomless (Group 1), 39 presented with a moderate climacteric syndrome (Group 2) and 16 had a severe climacteric syndrome (Group 3). The average body weight was found to be significantly higher in Groups 2 (P < 0.01) and 3 (P < 0.05), than in Group 1, but the age distribution and number of years since the menopause were similar in all three groups. Nevertheless, significantly lower levels of A (0.75± 0.06 ng/ml, P < 0.01, in Group 2; 0.24 ± 0.05 ng/ml, P < 0.001, in Group 3) and E₁ (20.80 ± 2.18 pg/ml, P < 0.05, in Group 2; 12.22 ± 1.65 pg/ml, P < 0.001, in Group 3) were observed in the women with climacteric symptoms than in those with no symptoms (A = 1.08 ± 0.08 ng/ml, E₁ = 27.73 ± 2.22 pg/ml in Group 1).

Since, after the menopause, the concentrations of A and E₁ in the plasma represent the most important source of oestrogens, these results suggest that climacteric symptoms are related to oestrogen deficiency which is secondary to low A production.     

Periodic abstinence enhances nociception without significantly altering the antinociceptive efficacy of spinal morphine in the rat

Affective disorders are more common in women. The forced swim test acts like a depressive stimulus. Hippocampus and frontal cortex 5-HT_1A receptors of female and male Wistar rats subjected to the forced swim test were compared with a sham group. The forced swim test diminishes (P<0.05) the hippocampus ³H-8OH-DPAT bound in the female rats (184±16 fmol/mg protein) with respect to the male rats (309±41 fmol/mg protein) and to the female sham rats (255±20 fmol/mg protein). The forced swim test increases the frontal cortex 5-HT_1A receptors in the female rats with respect to the female sham group (40.4±5 versus 24.7±4 fmol/mg protein, P<0.05). An increased sensibility of the 5-HT_1A receptors to depressive-stimulus may be one mechanism underlying the higher prevalence of depression in female.     

Glutamate transport in rat cerebellar granule cells is impaired by inorganic epileptogenic agents

There is evidence that extracellular glutamate levels are elevated in certain brain regions immediately prior to and during induction and propagation of seizures. There appears to be a correlation between the capacity of removing released glutamate and the genesis of epileptiform activity. Some models make use of metals, such as Co²⁺ and Ni²⁺, to induce epilepsy. We used patch-clamp recordings to measure the electrogenic glutamate transport in neuronal cells. The present results indicate that Co²⁺ (1 mM) and Ni²⁺ (5 mM) blocked glutamate transport by 17.6±3.9% (n=5, P<0.05) and by 31.8±6.2% (n=7, P<0.05), respectively. Ni²⁺ inhibited glutamate uptake in a dose-dependent manner. The IC₅₀ value obtained was 66.6 μM and the maximum inhibition was 40%. We conclude that one mechanism that may explain the seizures induced by exposure to those divalent cations is inhibition of the glutamate transporter.     

Food cravings during acute hypoglycaemia in adults with Type 1 diabetes

Background: Food craving is defined as an intense desire to eat a specific foodstuff. It may be distinguished from the sensation of hunger, which is relieved by nonspecific foodstuffs. No controlled studies have examined the effects of hypoglycaemia on food cravings. Thus, the aim of this study was to examine change in cravings for eight specified food types during euglycaemia and insulin-induced hypoglycaemia. Methods: Thirteen adults with Type 1 diabetes attended two experimental sessions where acute hypoglycaemia was induced with either insulin aspart or human soluble insulin. Food cravings were assessed, using a questionnaire, at baseline and at the onset of the autonomic reaction to hypoglycaemia (“R”). Results: The mean arterialised blood glucose concentration at baseline was 6.0±0.3 mmol l⁻¹ and at R was 1.9±0.4 mmol l⁻¹ (P<.01). Fifteen percent of subjects reported having a craving for food during euglycaemia. The prevalence increased to 65% during hypoglycaemia (P<.01). Cravings for seven of the eight food types increased during hypoglycaemia, but the greatest effect sizes (>1.0 standard deviations) were observed for three food types that had a high carbohydrate content. Conclusions: In people with Type 1 diabetes, acute hypoglycaemia produces a highly reliable generalised increase in cravings for food, particularly foodstuffs with a high content of carbohydrate. The mechanisms behind this response remain to be elicited.     

Beneficial effects of pravastatin in peri- and postmenopausal hyperlipidemic women: a 5-year study on serum lipid and sex hormone levels

Objectives: The aims of the present study are to assess the 5 year effects of pravastatin on serum lipids and lipoproteins in women around the menopause and to assess the effects of pravastatin on serum gonadotropins and sex steroid levels over a long-term period. Methods: We evaluated the long-term efficacy of pravastatin on serum lipid levels (total cholesterol, LDL-cholesterol, HDL-cholesterol, triglyceride) in 121 patients (47 premenopausal and 74 postmenopausal women) suffering from primary hypercholesterolemia. The effects of this lipid-lowering drug on serum gonadotropins and sex steroids (estradiol, estrone, and testosterone) are also reported. Results: Pravastatin produced a remarkable reduction in the serum total cholesterol level of 19.2±9.3% (P<0.0001) and 18.9±11.8% (P<0.0001), and in LDLl-cholesterol of 25.1±18.7% (P<0.0001) and 24±18.0% (P<0.0001) after 24 and 60 months’ treatment, respectively. In hypertriglyceridemia, pravastatin also produced a remarkable reduction in triglyceride of 29.3±27.3% (P<0.0001) and 39.9±20.4% (P<0.0001) after 24 and 60 months of treatment, respectively. We found that serum gonadotropins and sex steroid levels changed naturally as a function of age from pre-therapy levels in the premenopausal patients after 60 months of treatment. Conclusions: Pravastatin was well tolerated over 5 years and was a very effective lipid-lowering agent for both hypercholesterolemia and hypertriglyceridemia with no effect on the biosynthesis of sex steroids. These findings suggest that pravastatin can be used in the treatment of hypercholesterolemia with/without high triglyceride levels in women around the menopause.     

Diurnal preference, sleep habits, circadian sleep propensity and melatonin rhythm in healthy human subjects

After 24-h sleep deprivation, 33 healthy young subjects entered the 10/20 min ultra-short sleep–wake schedule for 26 h. Melatonin rhythm was hourly assessed simultaneously. Results indicated that morning preference was significantly correlated with habitual sleep onset (r=−0.41, P=0.04), habitual sleep offset (r=−0.52, P=0.002), melatonin peak time (r=−0.36, P=0.04), and sleep propensity onset time (r=−0.36, P=0.04). The intervals between habitual sleep mid-point and melatonin peak time and between habitual sleep mid-point and sleep propensity onset time were significantly longer in morning-preference subjects than in evening-preference subjects (P<0.05). These findings suggest that the variance of diurnal preference may be related to differences in phase relations between habitual sleep timing and the circadian pacemaker.