Vitamin D3 is well-known as a major regulator of calcium and
phosphorus homeostasis. A growing body of evidence highlights
its crucial role in the regulation of reproductive processes in
females. The role of vitamin D3 in the female reproductive tract
has been extensively investigated because its receptor is
abundant in reproductive organs, including ovary. Importantly,
besides expression of vitamin D3 receptor, the ovary is an
extrarenal site of vitamin D3 metabolism. The influence of vitamin
D3 on follicular development and ovarian steroidogenesis has
been investigated. Furthermore, vitamin D3 deficiency has also
been associated with polycystic ovary syndrome, premature
ovarian failure and ovarian cancer. The objective of this review is
to summarize our knowledge about the contribution of vitamin D3
to physiological and pathological processes within the ovary.
Suplementace přiměřenými dávkami vitaminů a stopových prvků je zcela nezbytná k prevenci rozvoje karenčních stavů. Nepřiměřený přívod může vést k závažným jevům (poruchy metabolismu, poškození volnými radikály, zpomalená reparace tkání atd.). Odpovídající příjem vitaminů je nutný jak u běžné populace, tak u rizikových skupin (děti, starší věkové skupiny) a u vážně nemocných, hospitalizovaných pacientů se zvýšenou spotřebou proteinů a energie. Všechny mikronutrientý (s výjimkou některých ve vodě rozpustných vitaminů) mohou být při vysokém příjmu toxické a neměly by být užívány bez indikace., Provision of adequate amounts of vitamins and trace elements is indispensable for prevention of clinical deficiency states and simultaneously inadequate supply may lead to the important effects (metabolic disturbances, free radical damage, insufficient repair of tissue etc.). Adequate intake of vitamins and trace elements is necessary in general healthy population as well as in groups at the risk (elderly individuals, children) and in seriously ill patients in hospital with increased requirements for protein and energy. All essential micronutrients (except of the some water soluble vitamins) could be toxic at high levels of intake and patients or healthy subjects should not take nutrient supplements unless they are clinically indicated., Zdeněk Zadák, Lit: 8, and Souhrn: eng
The vitellogenesis of Paraechinophallus japonicus (Yamaguti, 1934), the first pseudophyllidean tapeworm of the family Echinophallidae studied using transmission electron microscope, is described on the basis of ultrastructural observations of specimens from the benthopelagic fish Psenopsis anomala (Temminck et Schlegel, 1844) (Perciformes: Centrolophidae). The process of vitellogenesis in P. japonicus follows the same general pattern observed in other tapeworms. Five stages of vitellocyte development have been distinguished. The first stage corresponds to immature cells containing ribosomes and mitochondria. The second stage of development is characterized by the appearance of granular endoplasmic reticulum and Golgi complexes, formation of shell globules and lipid droplets at the periphery of the cell cytoplasm. Vitellocyte of the third stage presents accumulation of shell globules and lipid droplets. During the fourth stage, shell globule clusters are formed, and lipid droplets and rosettes of α-glycogen are accumulated. Mature vitelline cells are characterized by a great number of lipid droplets with glycogen in the centre of the cytoplasm, whereas shell globule clusters are situated more peripherally. The interstitial tissue of vitelline follicles of P. japonicus is syncytial with long cytoplasmic projections extending between vitelline cells. The presence of a large amount of lipid droplets in the vitelline cytoplasm within the eggs of P. japonicus may be related to egg accumulation in the uterine sac.