Use of progestogen-only contraceptives/medications and lipid parameters in women age 40 to 42 years: results of a population-based cross-sectional Norwegian Survey

This population-based cross-sectional study assessed lipid and lipoprotein parameters in women using progestogen-only contraceptives or medications and in those using no hormones. Unselected women about age 40 to 42 years were invited, and the participation rate was 65.6%. A total of 30,636 women were premenopausal, not pregnant, and used either a progestogen [n = 3000, including 2463 users of a intrauterine device (IUD) with levonorgestrel 20 microg/24 h] or no sex hormones. Those using the hormone-releasing IUD reported better health and a healthier lifestyle than nonusers of hormones, while women using depot medroxyprogesterone acetate had a less healthy lifestyle. Compared with nonusers of hormones, users of a levonorgestrel IUD were more likely to have high density lipoprotein (HDL)-cholesterol concentrations < or =1.1 mmol/L (odds ratio 1.4; 95% CI 1.2-1.5), while users of oral norethisterone or lynestrenol, or depot medroxyprogesterone acetate had a doubled to tripled risk of low HDL-cholesterol concentrations. Use of the IUD with levonorgestrel was also linked with a decreased risk of high serum triglycerides and of high non-HDL-cholesterol concentrations and a total/HDL-cholesterol ratio similar to that of nonusers of hormones.     

Influence of meptazinol on metabolic and hormonal responses following major surgery

Opioid drugs in high doses can obtund the stress response to major surgery but only at the expense of marked cardiorespiratory depression. The postoperative hormonal response to surgical stress was measured in 20 patients undergoing hysterectomy who were given either meptazinol 100 mg or morphine 15 mg intramuscularly at the end of the surgery. Both drugs at the doses used failed to diminish the stress response. Those patients who received meptazinol showed elevated prolactin levels: this may be an indicator of agonist activity at the mu 1 opioid receptor.     

Chronic mild stress induces behavioral and physiological changes,and may alter serotonin 1A receptor function,in male and cycling female rats

Rationale Interactions among stress, serotonin 1A (5-HT_1A) receptors, and the hypothalamic–pituitary–adrenocortical (HPA) system have been proposed to influence the development of depression in humans. The investigation of depression-relevant behaviors and physiological responses to environmental stressors in animal models of depression may provide valuable insight regarding these mechanisms.Objectives The purpose of these experiments was to investigate the interactions among central 5-HT_1A receptors, endocrine function, and behavior in an animal model of depression, chronic mild stress (CMS).Methods The current study examined behavioral responses to a pleasurable stimulus (sucrose), estrous cycle length (in female rats), and plasma hormone levels following systemic administration of a selective 5-HT_1A receptor agonist [(+)8-hydroxy-N,N-dipropyl-2-aminotetralin hydrobromide (8-OH-DPAT); 40 g/kg, s.c.; administered 15 min prior to sacrifice], in male and female rats exposed to 4 weeks of CMS.Results Four weeks of CMS produced a reduction in the intake of 1% sucrose (anhedonia), as well as attenuated adrenocorticotropic hormone (ACTH) responses to 8-OH-DPAT in both male and female rats (22 and 18% lower than the control groups, respectively). Corticosterone and oxytocin responses to 8-OH-DPAT were not altered by exposure to CMS. In female rats, CMS induced a lengthening of the estrous cycle by 40%.Conclusions CMS produces minor HPA disruptions along with behavioral disruptions. Alterations in 5-HT_1A receptor function in specific populations of neurons in the central nervous system may be associated with the CMS model. The current findings contribute to our understanding of the relations that stress and neuroendocrine function have to depressive disorders.     

Pre-test epinephrine injections reverse DDC-induced retrograde amnesia

The effects of pre-test systemic administration of epinephrine on DDC-induced retrograde amnesia (RA) for discriminated Pavlovian fear-conditioning were examined in rats. Epinephrine reversed RA with the optimal dosage being 0.05 mg/kg. Apparently, the effect was specifically reversal of amnesia since (a) performance was restored to control levels, but no higher, and (b) sensitization and activity-related artifacts were minimized. These results are consistent with those showing reversal of RA by pre-test administration of hormones or catecholamine agonists. That is, they suggest that amnesia is due to a retrieval deficit rather than to failure of memory storage. Results are discussed in terms of epinephrine-induced modulation of storage and retrieval processes through central and peripheral mechanisms.     

The role of the androgen receptor in CNS masculinization

The medial posterior region of the bed nucleus of the stria terminalis (BSTMP) and the locus coeruleus (LC) show opposite patterns of sexual dimorphism. The BSTMP in males is greater in volume and number of neurons than in females (male > female) while in the LC, the opposite is true (female > male). To investigate the possible role of the androgen receptor (AR) in the masculinization of these two structures, males with the testicular feminization mutation (Tfm) were compared to their control littermate males. No differences were seen in the number of neurons of the BSTMP between Tfm and their control littermate males, while in the LC, Tfm males have a greater number of neurons than their control littermate males. These results show that the AR is involved in the control of neuron number in the LC but not in the BSTMP. Results based on the LC suggest that when females have a larger brain area than males, masculinization in males may be achieved through the AR, with androgens perhaps decreasing cell survival.     

Women's sleep in health and disease

A huge amount of knowledge about sleep has accumulated during the last 5 decades following the discovery of rapid eye movement (REM) sleep. Nevertheless, there are numerous areas of considerable ignorance. One of these concerns the particularities of sleep in women. Most basic and clinical studies have been performed in male subjects, and only very recently research groups around the world have addressed women's sleep in health and disease. In this review, we summarize the present knowledge on the influence of oestrogens on the brain and on the distinctive changes of sleep across the menstrual cycle, during pregnancy and menopause. In addition, studies in female rodents are reviewed as well as the knowledge on female peculiarities regarding the interactions between sleep regulation and age-related changes in circadian rhythms. We also address specific aspects of sleep loss and sleep disorders in women. Finally, very recent studies on the sociology of sleep are summarized and future directions in the field are discussed.     

Ion transport across Xenopus alveolar epithelium is regulated by extracellular ATP, UTP and adenosine

Native alveolar epithelium from Xenopus lung was used for electrophysiological Ussing chamber experiments to investigate ion transport regulation. The tissue exhibits a considerable absorption of Na(+) ions and this transepithelial transport is largely up-regulated after treatment of donor animals with ACTH. Extracellular ATP, UTP and adenosine were tested for their regulating effects and all three increased I(sc), which was mainly due to a stimulation of amiloride sensitive Na(+) transport (increase of I(ami) 32% for ATP, 21% for UTP, 25% for adenosine). Solely the effect of UTP was completely abolished in the presence of amiloride. In contrast, the effects of ATP or adenosine disappeared under Cl(-)-free conditions. ATP and UTP proved to have additive effects and pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid (PPADS), an antagonist of purinergic receptors, inhibited selectively the effect of UTP on I(sc). Further, I(sc) was increased by the P2X selective agonist beta,gamma-meATP. We were able to demonstrate, that extracellular purines and pyrimidines play a possible role as auto/paracrine messengers for alveolar ion transport regulation in Xenopus lung.     

Hormonal changes during long-term isolation

Confinement and inactivity induce considerable psychological and physiological modifications through social and sensory deprivation. The aim of the SFINCSS-99 experiment was to determine the cardiovascular and hormonal pattern of blood volume regulation during long-term isolation and confinement. Simulation experiments were performed in pressurized chambers similar in size to the volumes of modern space vehicles. Group I consisted of four Russian male volunteers, who spent 240 days in a 100-m³ chamber. Group II included four males (one German and three Russians) who spent 110 days in isolation (200-m³ module). The blood samples, taken before, during and after the isolation period, were used to determine haematocrit (Ht), growth hormone (GH), active renin, aldosterone, and osmolality levels. From the urine samples, electrolytes, osmolality, nitrites, nitrates, cortisol, antidiuretic hormone (ADH), aldosterone, normetanephrine and metanephrine levels were determined. The increase in plasma volume (PV) that is associated with a tendency for a decrease in plasma active renin is likely to be due to decreased sympathetic activity, and concords with the changes in urinary catecholamine levels during confinement. Urinary catecholamine levels were significantly higher during the recovery period than during confinement. This suggests that the sympathoadrenal system was activated, and concords with the increase in heart rate. Vascular resistance is determined by not only the vasoconstrictor but also vasodilator systems. The ratio of nitrite/nitrate in urine, as an indicator of nitric oxide release, did not reveal any significant changes. Analysis of data suggests that the duration of the isolation was a main factor involved in the regulation of hormones.