Search results for "HORMONES"
showing 10 items of 1169 documents
The photoperiod entrains the molecular clock of the rat pineal.
2005
The suprachiasmatic nucleus-pineal system acts as a neuroendocrine transducer of seasonal changes in the photoperiod by regulating melatonin formation. In the present study, we have investigated the extent to which the photoperiod entrains the nonself-cycling oscillator in the Sprague-Dawley rat pineal. For this purpose, the 24-h expression of nine clock genes (bmal1, clock, per1, per2, per3, cry1, cry2, dec1 and dec2) and the aa-nat gene was monitored under light-dark 8 : 16 and light-dark 16 : 8 in the rat pineal by using real-time RT-PCR. The 24-h pattern of the expression of only per1, dec2 and aa-nat genes was affected by photoperiod. In comparison with the short photoperiod, the durat…
Influence of photoperiodic history on clock genes and the circadian pacemaker in the rat retina
2006
The influence of seasonal lighting conditions on expression of clock genes and the circadian pacemaker was investigated in the rat retina. For this purpose, the 24-h profiles of nine clock genes (bmal1, clock, per1, per2, per3, dec1, dec2, cry1 and cry 2) and the arylalkylamine N-acetyltransferase gene as an indicator of the circadian pacemaker output were compared between light-dark periods of 8 : 16 and 16 : 8 h. The photoperiod influenced the daily patterns of the amount of transcript for per1, per3, dec2 and arylalkylamine N-acetyltransferase. This indicates that photoperiodic information modulates clock gene expression in addition to the circadian pacemaker of the retina. Under constan…
The Effects of Chlorotrianisene (Tace) on Kinetics of 3H-testosterone Metabolism in Patients with Carcinoma of the Prostate
1982
Summary— Alterations in the metabolism of testosterone and plasma levels of testosterone, luteinising hormone (LH), follicle stimulating hormone (FSH), prolactin and oestradiol were studied in 6 patients with newly diagnosed prostatic carcinoma before and during treatment with chlorotrianisene at a daily dosage of 48 mg for 14 days. Parameters of plasma kinetics were determined according to the single injection technique and the 2-compartment model, and the plasma hormones by radioimmunoassay. Chlorotrianisene altered neither plasma levels of testosterone, gonadotrophins, prolactin and oestradiol, nor metabolic clearance rate, production rate and other kinetic parameters of testosterone. Th…
The role of the hypothalamic paraventricular nuclei for the regulation of pineal melatonin synthesis: New aspects derived from the vasopressin-defici…
1990
Abstract There is evidence for an involvement of the hypothalamic paraventricular nuclei (PVN) in the regulation of pineal melatonin synthesis in rats. Since electrical stimulation of the PVN or the systemic administration of arginine-vasopressin (AVP) result in a depression of the nocturnal melatonin surge, this neuropeptide appears to be pivotal for the transduction of PVN-efferent, pinealopetal signals. We therefore used an AVP-deficient animal model, the Brattleboro rat, to further investigate the mechanisms responsible for pineal regulation. Anesthetized adult male animals received 2 min of bilateral electrical stimulation of the PVN either during the day or at night. Thirty min later,…
The role of arginine-vasopressin for pineal melatonin synthesis in the rat: involvement of vasopressinergic receptors.
1991
Abstract The endogenously synthesized nonapeptide arginine vasopressin (AVP) is thought to be involved in transduction of photic information to the pineal gland. The enhancement of circulating AVP leads to a suppression of the nocturnal melatonin surge the mechanisms of which are unknown so far. We therefore studied the effect of dDAVP, an AVP analog with antidiuretic but without vasopressor activity, on pineal melatonin synthesis in Sprague-Dawley and AVP-deficient Brattleboro rats. The nocturnal intra-arterial application of dDAVP mimicked the inhibitory effect of AVP on the activity of the rate-limiting enzyme for pineal melatonin synthesis, N-acetyltransferase (NAT), in both rat strains…
Comparative investigations on the actions of ACTH1-24, somatostatin, neurotensin, substance P and vasopressin on locus coeruleus neuronal activity in…
1987
A considerable number of neuropeptides have been localized immunohistochemically in the area of the locus coeruleus of the rat. The objective of this study was to assess the actions of some of these transmitter candidates on spontaneously active locus coeruleus neurons in vitro. The effects of bath-applied peptides on the discharge rate of individual locus coeruleus neurons were investigated. A midpontine slice preparation of the gerbil brain was used. Excitatory dose-dependent effects were found with four peptides with the following rank order of potency: Substance P, (Arg8)-vasopressin, neurotensin, ACTH1–24. Somatostatin hyperpolarized all neurons tested. Given the pronounced effects see…
The effects of sex hormones, prolactin, and chorionic gonadotropin on pineal electrical activity in guinea pigs.
1981
Microelectrophoretic application of sex hormones onto pineal cells in guinea pigs has shown different responses in pregnant females as compared to males. In pregnant females estrone caused excitation in 74% of the cells tested, while progesterone and testosterone, prolactin, and HCG were inhibitory in a majority of the cells tested, while progesterone and testosterone, prolactin, and HCG were inhibitory in a majority of the cells. In contrast, in males estrone caused excitation of only 19% but inhibition of 37%. A smaller percentage of cells was inhibited by progesterone, while the predominant response to testosterone was excitation. These results suggest that the pineal gland may be under …
Testosterone metabolism in patients with advanced carcinoma of the prostate: a comparative in vivo study of the effects of oestrogen and antiprolacti…
1978
In the light of the high incidence of cardiovascular side effects with oestrogen therapy in patients with prostatic cancer, other medications altering androgen metabolism are under investigation. The influence of the anti-prolactin bromocriptine (CB154) on plasma kinetics of testosterone and on endogenous hormones was studied and compared with the effect of ethinyl oestradiol in 25 patients with prostatic carcinoma. Bromocriptine significantly suppressed both prolactin and testosterone, inhibited the transfer of androgen from the inner pool into the deep compartment and favoured its degradation. Ethinyl oestradiol decreased testosterone, LH and FSH, and prolonged the biological half-life of…
Perioperative pupil size in low-energy femtosecond laser-assisted cataract surgery
2020
Purpose To assess potential changes in pupil size during femtosecond laser-assisted cataract surgery (FLACS) using a low-energy laser system. Methods The pupil sizes of eyes undergoing FLACS were measured using the Ziemer LDV Z8 by extracting images from the laser software after each of the following steps: application of suction, lens fragmentation, and capsulotomy. Furthermore, the pupil diameters were measured based on preoperative surgical microscope images and after releasing the suction. Paired t-test and the two one-sided tests (TOST) procedure were used for statistical analyses. The horizontal and vertical pupil diameters were compared in each of the steps with preoperative values.…
Hospital Care of Older Patients With COPD: Adherence to International Guidelines for Use of Inhaled Bronchodilators and Corticosteroids
2019
Abstract Objectives We aimed to analyze the prevalence and impact of COPD in older patients hospitalized in internal medicine or geriatric wards, and to investigate adherence to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines, associated clinical factors, and outcomes. Design Data were obtained from REgistro POliterapie SIMI (REPOSI), a prospective multicenter observational registry that enrolls inpatients aged ≥65 years. Setting and Participants Older hospitalized patients enrolled from 2008 to 2016 with a diagnosis of COPD. Measures We evaluated adherence to the 2018 GOLD guidelines at admission and discharge, by examining the prescription of inhaled bronchodi…