Important exogenous factors that mutually affect and regulate the annual sexual cycle of lizards, in the ecological context of adaptation, are environmental (rain, temperature, humidity, photoperiod, ...etc.), structural (vegetation change, food availability, etc.) and social factors (behavioural interaction, experience, etc.), while in some species endogenous (circa-annual) rhythmicity may prevail. Both endogenous and exogenous factors determine the time of hatching in the season providing the highest chances of survival for offspring. Hormonally controlled processes via the hypothalamus- pituitary-gonadal axis produce a cascade of events that determine the reproductive processes involved in reproduction, and can be found in all lizard species. These hormones, in addition to being necessary for successful reproduction and survival of the species, have numerous roles in physiology, metabolism and behaviour. The beginning, duration and end of the breeding season, and the duration of sexual inactivity, differ significantly by species and geographical distribution. Although there is much knowledge about reptile reproduction and its regulation, there are still hidden secrets and specificities in many species that have not yet been discovered or fully explained.
Važni egzogeni čimbenici koji međusobno utječu i reguliraju godišnji spolni ciklus guštera, u ekološkom kontekstu prilagodbe, su: okolišni (kiša, temperatura, vlaga, fotoperiod i dr.), strukturni (promjena vegetacije, dostupnost hrane i dr.) i društveni čimbenici (interakcija ponašanja, iskustvo itd.), a kod nekih vrsta može prevladati i endogena (cirkaanualna) ritmičnost. Endogeni i egzogeni čimbenici određuju vrijeme izlijeganja u sezoni u kojoj je preživljavanje potomaka najveće. Hormonski kontrolirani procesi preko osovine hipotalamus-hipofiza-gonade proizvode kaskadu događaja koji određuju reproduktivne procese uključene u reprodukciju, a mogu se naći kod svih vrsta guštera. Ovi hormoni, osim što su nužni za uspješnu reprodukciju i opstanak vrste, imaju brojne uloge u fiziologiji, metabolizmu i ponašanju. Početak, trajanje i kraj sezone parenja, kao i trajanje sezone spolne neaktivnosti, značajno se razlikuju ovisno o vrsti i geografskoj rasprostranjenosti guštera. Iako postoje mnoga saznanja o razmnožavanju gmazovai njegovoj regulaciji, još više skrivenih tajni i specifičnostikod mnogih vrsta, nisu otkrivene niti do kraja razjašnjene.
Pretilost predstavlja jedan od najvećih zdravstveno-ekonomskih i socijalnih problema današnjice te se sve veća učestalost pretilosti povezuje s porastom incidencije i pobola niza drugih bolesti, ...prije svega šećerne bolesti, kardiovaskularnih i cerebrovaskularnih oboljenja te malignih bolesti. U održavanju ravnoteže unosa i potrošnje energije najvažniju regulatornu ulogu ima središnji živčani sustav, odnosno osovina mozak-crijevo, koja se temelji na funkciji niza gastrointestinalnih peptidnih hormona. Djelovanje navedenih peptida izrazito je raznoliko i ovisi o nizu čimbenika, posebno vrsti i količini hrane, energetskom stanju organizma te pratećim bolestima i metaboličkim poremećajima. Djelovanje ovih hormona usko je povezano s endokrinom funkcijom gušterače, lučenjem inzulina i regulacijom glikemije, što ujedno ukazuje i na jasnu povezanost pretilosti i šećerne bolesti. Velik napredak na području razvoja i primjene novih antidijabetika u klasi peptidnih hormona, odnosno inkretina, te utvrđivanje njihovih dodatnih svojstava u smislu redukcije tjelesne težine, otvorili su tijekom posljednjih godina čitavo novo područje istraživanja farmakoterapije pretilosti. Obećavajuće rezultate prije svega pružaju nove mogućnosti kombinacije više lijekova, čime se ponovno stvara mogućnost razvoja adekvatne farmakoterapije kao alternative kirurškom pristupu liječenju pretilosti.
Reproductive toxicity of metals in men Pizent, Alica; Tariba, Blanka; Živković, Tanja
Arhiv za higijenu rada i toksikologiju,
2012, Volume:
63 Suppl 1, Issue:
Supplement-1
Journal Article
Peer reviewed
Open access
A combination of genetic, environmental and lifestyle factors contributes to adverse effects on the reproductive health in men. Metals are pervasive in food, water, air, tobacco smoke, and alcoholic ...beverages. Experimental studies suggest that many metals have adverse effects on the male reproductive function. However, information about reproductive effects of human exposure to metals is scarce and/or inconsistent. This review summarises the information from epidemiological studies of the effects of metal exposure on reproductive function in men. Factors capable of affecting these relationships were identified and discussed. A particular attention is given to the studies considering influence of concomitant exposure to various metals. These studies have generally confirmed that even moderate- to low-level exposure to lead affects certain reproductive parameters, and that exposure to cadmium affects the prostate function and serum testosterone levels. Adverse effects of mercury, manganese, chromium and arsenic on semen quality and altered serum hormone are less well documented. There is no clear evidence that boron exposure may impair reproductive health in men. Only a few studies have investigated reproductive effects of concomitant exposure to several metals and controlled for potential confounders. Future studies should consider the contribution of combined exposure to various metals and/or other factors that may influence individual susceptibility to reproductive health impairment in men.
Spolni hormoni, poput testosterona, su tvari koje sintetiziraju spolne žlijezde. Riječ je o tvarima koje su uključene u endokrinu regulaciju rasta, kao i u razvoj spolnih karakteristika, kako u ...životinjskom, tako i u ljudskom organizmu. Spolni hormoni imaju čitav niz vrlo bitnih funkcija u organizmu. Osim na razvoj spolnih karakteristika, spolni hormoni mogu utjecati i na još nekoliko bitnih segmenata, poput rasta te se stoga upotrebljavaju u terapijske i anaboličke svrhe. Postoje četiri skupine spolnih hormona i to: androgeni, estrogeni, gestageni te relaksini. Cilj ovog rada je dati pregled literature o uporabi spolnih hormona u terapijske i anaboličke svrhe s naglaskom na testosteron. Naime, testosteron je najvažniji prirodni androgen koji se izlučuje u testisima te stimulira razvoj muških spolnih žlijezda te spolnih karakteristika, a najčešće se koristi u kombinaciji sa 17β-estradiolom. U radu se posebno ističe negativno djelovanje testosterona koji pri medicinski neopravdanoj uporabi može prouzročiti i mutacije gena te pojavu tumora. Što se tiče uporabe u terapijske svrhe, spolni hormoni, uključujući testosteron, mogu se opravdano koristiti kako bi se prevenirali i smanjili zdravstveni problemi u reproduktivnom sustavu. S druge strane, njihova neprimjerena uporaba u cilju poboljšanja rasta i ostvarivanja financijske dobiti, odnosno u anaboličke svrhe, nije legalna s obzirom da mogu negativno djelovati ne samo na životinje, nego i na ljude kao konzumenta hrane životinjskog podrijetla. Slijedom toga, u proizvodnji konzumnih životinja zakonom je regulirana uporaba spolnih hormona, uključujući i testosteron. Osim nadležnih tijela vrlo bitnu ulogu u nadzoru ovih tvari, imaju i veterinarske službe i referentni laboratoriji. U budućnosti je potrebno pronaći alternativna rješenja za terapijsku primjenu hormona u farmskih životinja, a sustavi kontrole trebaju biti vrlo učinkoviti kako bi se isključila mogućnost zlouporabe ovih tvari u anaboličke svrhe.
Ferritin is the main intracellular storage of iron. Animal studies show that female liver and kidney express more ferritin and accumulate more iron than male. However, no study so far has ...investigated sex and age differences in light (FtL) and heavy (FtH) ferritin chain expression. To address this, we relied on specific antibodies and immunochemical methods to analyse the expression of both ferritin chains in the liver and kidney of 3-month and 2-year-old male and female Wistar rats. To see how sex hormones may affect expression we also studied adult animals gonadectomised at the age of 10 weeks. FtL and FtH were more expressed in both organs of female rats, while gonadectomy increased the expression in males and decreased it in females, which suggests that it is stimulated by female and inhibited by male steroid hormones. Normal kidney ferritin distribution and change with aging warrant more attention in studies of (patho) physiological and toxicological processes.
Od demencije češće boluju žene Uzun, Suzana; Todorić Laidlaw, Ivana; Kušan Jukić, Marija ...
Socijalna psihijatrija,
03/2018, Volume:
46, Issue:
1
Journal Article
Open access
Demencija je sindrom globalnog i progresivnog oštećenja stečenih kognitivnih sposobnosti pri očuvanoj svijesti prouzročen organskom bolešću središnjeg živčanog sustava u kojem su posebno oštećene ...sposobnosti pamćenja, učenja, apstraktnog mišljenja, orijentacije te poimanja vidno‐prostornih odnosa. Prevalencija i incidencija
Alzheimerove bolesti (AB), najčešćeg uzroka demencije, znatno je veća kod žena nego kod muškaraca, a ta se razlika s dobi povećava. Dvostruko veća učestalost AB kod žena u odnosu na muškarce djelomično se može objasniti time što žene imaju očekivano dulji životni vijek. Žene imaju lošiju kognitivnu izvedbu na mnogim neuropsihologijskim testovima u odnosu na muškarce u istom stadiju bolesti, odnosno višestruke kognitivne funkcije kod žena teže su i
šire zahvaćene nego kod muškaraca. Mogući razlozi za ovakvu nepovoljnost naspram žena su redukcija estrogena u postmenopauzi, veće kognitivne rezerve muškaraca te utjecaj apolipoproteina E. Određeni biološki čimbenici također bi mogli objasniti različite kliničke manifestacije AB s obzirom na spol. Osim što prema prezentiranim
podatcima žene češće obolijevaju od AB, žene su također te koje u bitno većoj mjeri pružaju neformalnu njegu ljudima s demencijom, te su oko dvije trećine neformalnih njegovatelja žene. Zaključno, u daljnjem istraživačkom i kliničkom radu s AB svakako bi trebalo obratiti pozornost na spoznaje o spolnim razlikama u razvoju i progresiji ove bolesti.
Oxidative stress plays a role in the pathogenesis of many chronic diseases. It is recognized in overt hypothyroidism while its existence in subclinical hypothyroidism (SCH) is not well established. ...The aim of this study was to determine whether there was increased oxidation of lipids and proteins in SCH, and examine their association with lipids and thyroid hormones.
Male adults (35-59 years) with SCH (n=467) and euthyroid controls (n=190) were studied. Anthropometric measurements, plasma lipids, thyroid stimulating hormone (TSH), free thyroxine (FT4), free triiodothyronine (FT3), total antioxidant capacity (T-AOC), lipid peroxidation products, malondialdehyde (MDA), advanced oxidation protein products (AOPP) and dityrosine concentrations were measured.
Plasma concentrations of MDA were significantly higher (p<0.05) in SCH (8.11±1.39 nmol/mL) compared with euthyroid controls (7.34±1.31 nmol/mL) while AOPP, dityrosine and T-AOC levels were not different. MDA was not associated with TSH (β=-0.019, P=0.759), FT4 (β=-0.062, P=0.323) and FT3 (β=-0.018, P=0.780) in SCH while levels increased with elevated total cholesterol (β=0.229, P=0.001), LDL (β=0.203, P=0.009) and triglycerides (β=0.159, P=0.036) after adjustment for age and body mass index. T-AOC reduced (β=-0.327, P=0.030) with increased MDA in euthyroid controls and not in SCH (β=-0.068, P=0.349), while levels increased with elevated triglycerides in both groups.
Oxidative stress was increased in subclinical hypothyroidism as evidenced by the elevated lipid peroxidation product, malondialdehyde, while protein oxidation was absent. Thus, reduction of oxidative stress may be beneficial in patients with subclinical hypothyroidism.
Although vitamin D in not a traditional marker for cardiovascular and renal diseases, several studies have proposed a correlation between vitamin D deficiency and these diseases due to the effect of ...vitamin D on endothelial function. Asymmetric and symmetric dimethyl arginine (ADMA and SDMA, respectively) are endogenous markers of endothelial dysfunction, and are considered as future markers for the assessment of cardiovascular and renal diseases. The present study investigated the association of kidney function tests (urea and creatinine) and dimethylarginine toxins (ADMA and SDMA) in women with vitamin D insufficiency or deficiency. Indeed, sex hormones (estrogen and testosterone) were analyzed in the participants.
Women were divided into two groups: premenopausal women (younger than 50 years) and postmenopausal women (older than 50 years). Urea, creatinine, estrogen, testosterone, ADMA, and SDMA levels were analyzed when vitamin D level was deficient or insufficient in the participants.
The premenopausal women group showed no significant correlations between dimethylarginine toxins and renal failure tests or sex hormones. In the elderly (postmenstrual) women group, only SDMA was significantly correlated with urea and creatinine, while both ADMA and SDMA were not correlated with sex hormones.
Although ADMA and SDMA are promising candidates of endothelial dysfunction and are increased in menopause and aging, no direct link between ADMA and further progression of renal failure was observed in women with low vitamin D levels. In contrast, a possible direct correlation between SDMA and renal dysfunction was noticed, but only in an age-dependent manner.
Regulacija apetita vrlo je kompleksna budući da u njoj sudjeluje veliki broj organa i njihovih hormonalnih molekula. Probavni sustav sa preko 40 hormonalnih molekula predstavlja najveći endokrini ...organ koji sudjeluje u regulaciji apetita. S obzirom na način djelovanja na apetit probavni hormoni mogu se podijeliti na stimulatrore apetita: grelin (hornom gladi) i obestatintin, i supresore apetita: kolecitokinin (CCK), hormon PYY3-36, oksintomodulin (OXM), GLP-1 (peptid-1 nalik glukonu) i PP hormon, te probavne hormone koji su indirektno uključeni u njegovu regulaciju: sekretin i gastin. Poremećaji u lučenju ovih hormona prisutni su kod dijabetičara i pretilih osoba.
Oxidative stress plays a role in the pathogenesis of many chronic diseases. It is recognized in overt hypothyroidism while its existence in subclinical hypothyroidism (SCH) is not well established. ...The aim of this study was to determine whether there was increased oxidation of lipids and proteins in SCH, and examine their association with lipids and thyroid hormones.
Methods: Male adults (35-59 years) with SCH (n=467) and euthyroid controls (n=190) were studied. Anthropometric measurements, plasma lipids, thyroid stimulating hormone (TSH), free thyroxine (FT4), free triiodothyronine (FT3), total antioxidant capacity (T-AOC), lipid peroxidation products, malondialdehyde (MDA), advanced oxidation protein products (AOPP) and dityrosine concentrations were measured.
Results: Plasma concentrations of MDA were significantly higher (p<0.05) in SCH (8.11±1.39 nmol/mL) compared with euthyroid controls (7.34±1.31 nmol/mL) while AOPP, dityrosine and T-AOC levels were not different. MDA was not associated with TSH (β=-0.019, P=0.759), FT4 (β=-0.062, P=0.323) and FT3 (β=-0.018, P=0.780) in SCH while levels increased with elevated total cholesterol (β=0.229, P=0.001), LDL (β=0.203, P=0.009) and triglycerides (β=0.159, P=0.036) after adjustment for ageand body mass index. T-AOC reduced (β=-0.327, P=0.030) with increased MDA in euthyroid controls and not in SCH (β=-0.068, P=0.349), while levels increased with elevated triglycerides in both groups.
Conclusion: Oxidative stress was increased in subclinical hypothyroidism as evidenced by the elevated lipid peroxidation product, malondialdehyde, while protein oxidation was absent. Thus, reduction of oxidative stress may be beneficial in patients with subclinical hypothyroidism
Uvod: Oksidativni stres učestvuje u patogenezi mnogih hroničnih oboljenja. Ima ulogu u manifestnoj hipotireozi, dok njegovo prisustvo u subkliničkoj hipotireozi (SH) nije sasvim razjašnjeno. Cilj ove studije bio je da se odredi da li postoji povišena oksidacija lipida i proteina u SH i da se istraži njihova povezanost sa lipidima i tireoidnim hormonima.
Metode: Ispitivani su odrasli muškarci (35-59 godina) sa SH (n=467) i eutireoidne kontrolne osobe (n=190). Izmereni su antropometrijski parametri, koncentracije lipida u plazmi, tireostimulišućeg hormona (TSH), slobodnog tiro- ksina (FT4), slobodnog trijodtironina (FT3), ukupni antioksidantni kapacitet (T-AOC), proizvodi lipidne peroksidacije, malondialdehid (MDA), uznapredovali proizvodi proteinske oksidacije (AOPP) i ditirozin.
Rezultati: Koncentracije MDA u plazmi bile su značajno povisene (p<0,05) u SH (8,11 ±1,39 nmol/mL) u poredenju sa eutireoidnim kontrolnim osobama (7,34±1,31 nmol/mL) dok se nivoi AOPFJ ditirozina i T-AOC nisu raz- likovali. MDA nije bio povezan sa TSH (p =-0,019, P=0,759), FT4(p=-0,062, P=0,323) i FT3 (p=-0,018, P=0,780) u SH dok su nivoi rasli s povisenim vrednostima ukupnog holesterola (p = 0,229, P=0,001), LDL(p = 0,203, P= 0,009) i triglicerida (P = 0,159, P= 0,036) posle prila-gocfavanja za starost i indeks telesne mase. Porast nivoa MDA bio je pracen snizenjem nivoa T-AOC (P=-0,327, P=0,030) kod eutireoidnih kontrolnih osoba, ali ne i u SH (P=-0,068, P=0,349), dok su u obe grupe nivoi rasli s porastom triglicerida.
Zaključak: Oksidativni stres bio je povišen u subkliničkoj hipotireozi, što su pokazali i povišeni nivoi proizvoda lipidne peroksidacije, malondialdehida, dok je oksidacija proteina bila odsutna. Stoga, snižavanje oksidativnog stresa može biti korisno kod pacijenata sa subkliničkom hipotireozom
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