Menarcheal age of mothers and daughters: Tehran lipid and glucose study.

There is some evidence for a decreasing age of menarche in many populations. This study examined the secular trend of age at menarche among Iranian women. Age at menarche based on recall information was recorded for 770 pairs of mother and daughters. Between 1930 and 1990 mean menarcheal age of this cohort of women decreased from 13.88 to 12.98 years (-0.15 years per decade) and mean height of the cohort increased from 152.33 to 158.43 cm (+0.99 cm per decade). There was a significant correlation between menarcheal age of mothers and their daughters (r = 0.27). Year of birth, mother's menarcheal age and daughter's height were significant predictors of daughter's menarcheal age.

Menarcheal age of mothers and daughters: Tehran Lipid and Glucose Study

There is some evidence for a decreasing age of menarche in many populations. This study examined the secular trend of age at menarche among Iranian women. Age at menarche based on recall information was recorded for 770 pairs of mother and daughters. Between 1930 and 1990 mean menarcheal age of this cohort of women decreased from 13.88 to 12.98 years [-0.15 years per decade] and mean height of the cohort increased from 152.33 to 158.43 cm [+0.99 cm per decade]. There was a significant correlation between menarcheal age of mothers and their daughters [r = 0.27]. Year of birth, mother's menarcheal age and daughter's height were significant predictors of daughter's menarcheal age

The effect of intra-hippocampal injection of growth hormone on spatial learning and memory in animal model of Alzheimer's disease.

The aim of this study was to evaluate the effect of intra-hippocampal injection of Growth Hormone (GH) on impaired spatial cognition in rats with Alzheimer's Disease (AD). Growth hormone replacement therapy leading to improved cognition and well-being has mainly been carried in GH-deficient patients. Nevertheless, relatively only a few studies have investigated the function of GH in the brain. Aged Wistar male rats (350-400 g, 18-20 months old) were randomly divided into 6 groups (7 in each): Control (healthy aged); L; L + Veh; L + GH10; L + GH20 and L + GH40. Rats with AD-like cognitive deficiency was induced by injection of ibotenic acid into Nucleus Basalis of Meynert (NBM) bilaterally (5 microg 0.5 microL(-1), each side). A guide cannula was implanted in the right hippocampus under stereotaxic surgery for injection of human recombinant GH (10, 20 and 40 microg 2 microL(-1), during 5 min, twice daily, 9:00 am and 3:00 pm, for 7 days). All rats were trained in Morris water maze to evaluate the spatial learning and memory. Escape latency, traveled distance to find hidden platform and percent time spent in gaol qudrant did not differ between L and L + Veh groups, while latency and distance were reduced significantly. But percent time spent in gaol quadrant (without hidden platform) was increased significantly in NBM-lesioned rats treated with GH (L + GH groups) dose dependently to compare with vehicle treated group. These results suggest that intra-hippocampal injection of GH to aged rats with dementia type of AD (with NBM lesioned) could improve spatial cognition.

Prevalence of metabolic syndrome during menopausal transition Tehranian women: Tehran Lipid and Glucose Study (TLGS).

OBJECTIVE: This study was conducted to assess the prevalence of metabolic syndrome (MetS) in Tehranian women during menopausal transition. DESIGN: In this cross sectional study 2182 subjects, pre-menopausal (pre-M) n=537, menopausal (M) n=311 and post-menopausal (post-M) n=1334 were selected from 15005 participants of the TLGS and assessed for MetS risk factors. All MetS components were evaluated following age adjustment according to the ATPIII criteria. RESULTS: The mean ages of post-M, M and pre-M women were 61.0+/-4.3, 53.0+/-4.0 and 47.0+/-1.9 years, respectively. The prevalence of MetS in subjects was 63% (53%, 54% and 69%) in pre-M, M and post-M women respectively. HDL-c levels was significantly higher in post-M women in comparison to pre-M women (p<0.001). TG levels, FPG and waist circumference was significantly higher in post-M women in comparison to pre-M women (p<0.05). The most frequent markers of MetS were low HDL-c and high diastolic blood pressure in post-M women. CONCLUSION: It is concluded that the frequency of MetS is significantly higher in post-M women as compared to pre-M women; low HDL-c and high diastolic blood pressure is the most frequent feature in comparison to other factors.

The effects of insulin on glucose and fluid transport in the isolated small intestine of normal rats.

Chronically administered insulin returns enhanced maximal glucose transport capacity induced by diabetes to its normal state. In this study, the direct and acute effects of insulin on glucose transport in different parts of isolated small intestine were investigated. Mucosal Fluid Transport (MFT), Mucosal Glucose Transport (MGT) and Serosal Glucose Transport (SGT) were measured in the presence and absence of insulin in averted sacs, prepared from female Wistar rats. This study shows that the presence of insulin in vitro (40 and 80 microU/mL) can reduce MGT and SGT in different segments of the small intestine (duodenum, jejunum and ileum) after 30 min whereas it had no effect on MFT. Mucosal glucose transfer rates in the duodenum, jejunum and ileum of the controls were 6.07+/-0.4, 6.34+/-0.62 and 6.43+/-0.47 mg/g tissue respectively which were significantly reduced to 3.82+/-0.93, 3.60+/-0.50 and 1.17+/-0.45 in the presence of 80 microU/mL of insulin. Serosal glucose transfer too was decreased significantly from 0.3+/-0.05, 0.57+/-0.07 and 0.43+/-.07 in the duodenum, jejunum and ileum to 0.16+/-0.03, 0.16+/-0.04 and .07+/-.02 respectively. Mucosal fluid transfer was not affected by insulin. Insulin was as effective whether it was added on the mucosal or the serosal side. The results of this study show that insulin can directly affect glucose transport in the small intestine; its physiological role must be examined. Direct effect of insulin deficiency on glucose absorption in diabetic patients may play a role in the pathophysiology of the disease.

Insulin protects against stress-induced impairments in water maze performance.

The presence of insulin receptor in the hippocampus suggests that this organ is a target for insulin. However, unlike the classic peripheral insulin target tissues such as adipocyte, muscle and liver, where the primary function of insulin is to regulate glucose homeostasis, insulin in the central nervous system (CNS) exhibits more diverse actions, most of which have not been clearly understood. A direct role of hippocampal insulin receptor signaling in improving cognitive functions, including learning and memory, and the association of insulin receptor deterioration with brain degenerative dementia (e.g., Alzheimer's disease) have attracted increasing interest. Additionally it has been shown that insulin can be a neuroprotective agent against memory loss induced by ischemia, lesions and some pharmacological agents. In the present study we evaluate the hypothesis that the bilateral intra CA1 insulin injection can protects against stress-induced memory deficit. Chronic restraint stress (2h per day x 7 days) significantly impaired spatial performance in Morris water maze and elevated serum corticosterone level. Intrahippocampal insulin microinjection was done 15-20 min before every stress episode. Insulin in low dose (0.5 MU) had no significant effect on memory deficit induced by stress. But in higher doses (6 and 12 MU) insulin protects animals against the deleterious effect of stress. Insulin alone daily injection had no effect on water maze performance. These results suggest that spatial learning and memory is compromised during chronic stress and insulin may protect against this effect.

The effect of intrahippocampal insulin microinjection on spatial learning and memory.

Insulin is best known for its action on peripheral target tissues such as the adipocyte, muscle and liver to regulate glucose homeostasis. Insulin and its receptor are found in specific area of CNS with a variety of region-specific functions different from its direct glucose regulation in the periphery. The hippocampus and cerebral cortex distributed insulin/insulin receptor has been shown to be involved in brain cognitive functions. Previous studies about the effect of insulin on memory are controversial. In the present study, the effect of insulin microinjection into CA1 region of rat hippocampus on water maze performance has been investigated. Insulin had a discrepant effect dose dependently. The spatial learning and memory were impaired with lower dose of insulin, had not changed with intermediate doses, while they improved with higher doses. These results suggest that insulin may have a dose-dependent effect on spatial learning and memory.

Effect of chronic psychological stress on insulin release from rat isolated pancreatic islets.

Despite documented studies, the exact role of stress on diabetes is still unclear. The present study investigates the effect of chronic psychological stress on insulin release from isolated rat pancreatic islets. Male Wistar rats were divided into two groups of control and stressed (n=8/group). The animals of the stressed group were exposed to restraint stressors (1 h twice daily) for 15 or 30 consecutive days. At the beginning and end of the experimental periods, the animals were weighed and blood samples taken to determine the fasting plasma levels of glucose, insulin and corticosterone. On the following day the pancreatic islets of 5/group of the above animals were isolated and the static release of insulin in the presence of different glucose concentrations (2.8, 5.6, 8.3, 16.7 mM) was assessed. The results showed that in the stressed group, fasting plasma glucose levels were increased significantly on the 15th day as compared to the control group. However there was no significant increase on the 30th day. Fasting plasma insulin was significantly decreased on the 15th and 30th days of the experiment in the stressed group. Stressed rats showed significantly higher fasting plasma corticosterone levels, only on the 15th day, as compared to the control rats. In response to increasing concentrations of glucose, insulin release from islets of the stressed group was increased significantly on the 30th day of the experiment as compared to the control group. We conclude that chronic psychological stress could increase responsiveness of pancreatic beta cells to glucose, in vitro, and thus, low insulin levels of the stressed animals, in vivo, may be due to reason(s) other than the reduction of insulin releasing capacity of pancreatic beta cells.

Effect of jejunoileal bypass in the rat on the enteroinsular axis.

The effect of jejunoileal bypass (JIB) on the enteroinsular axis was studied in vivo and in vitro in the rat. Glucose, insulin and GIP responses to oral glucose were compared in JIB and control rats. The effect of glucose and GIP on insulin release from the isolated perfused pancreas of the same animals was investigated to determine if JIB altered the sensitivity of the beta cell. Immunocytochemical studies of gut and pancreas were also carried out. Glucose, insulin and GIP responses to a glucose load were blunted after JIB, although basal GIP levels were elevated in these animals. The insulin response of the perfused JIB pancreas to GIP was 70% reduced from controls although the insulin response to glucose appeared normal. The size and area of JIB islets were unchanged from controls as was the distribution of insulin, glucagon, somatostatin and pancreatic polypeptide. GIP immunoreactive cells were present in all regions of the intestine including the JIB blind loop. This study confirms the findings of others that a relationship exists between reduced GIP and insulin response to oral glucose after JIB, and indicates that a decrease in sensitivity of the beta cell to GIP occurs following JIB that is not rapidly reversible. GIP secreted from blind loop mucosa may contribute to the high basal GIP found in JIB rats and may be causally connected to the fall in beta cell sensitivity.