The general aim of our in vitro experiments was to study the role of the metabolic hormones leptin, ghrelin, obestatin and IGF-I and mitogen-activated protein kinase (MAPK)-dependent intracellular mechanisms in the control of nuclear maturation of porcine oocytes. For this purpose, porcine oocytes were isolated from the ovary and cultured in the presence of leptin, ghrelin, obestatin, IGF-I, MAPK blocker PD98059 and the combinations of hormones with PD98059. Proportions of matured oocytes (at metaphase II of meiosis, determined by DAPI staining) and of oocytes containing MAPK/ERK1-2 (determined by immunocytochemistry) were measured before and after culture. It was observed that the majority of oocytes isolated from the ovary before culture were immature and did not contain visible MAPK, but some oocytes were mature, and the majority of these oocytes contained MAPK. Incubation of oocytes resulted in a significant increase in the proportion of matured oocytes and in the percentage of oocytes containing MAPK in both the matured and not matured groups. Addition of IGF-I to the culture medium increased the proportion of matured oocytes, addition of leptin decreased it, and ghrelin and obestatin did not oocyte maturation. Addition of hormones did not affect the expression of MAPK in either immature or mature oocytes. PD98059, when given alone, suppressed the maturation and accumulation of MAPK in both mature and immature oocytes. When given together with hormones, PD98059 was able to reduce the stimulatory effect of IGF-I, to invert the inhibitory action of leptin to stimulatory and to induce the stimulatory action of ghrelin and obestatin on meiosis. IGF-I, ghrelin and obestatin, but not leptin, when given together with PD98059, increased the accumulation of MAPK in both immature and mature oocytes. Association of nuclear maturation and expression of MAPK in oocytes before, but not after culture, as well as the prevention of oocyte maturation by MAPK blocker suggests the involvement of MAPK-dependent intracellular mechanisms in the promotion of reinitiation, but not completion of meiosis. The effect of hormonal additions on meiosis of oocytes suggests that IGF-I is a stimulator, leptin can be an inhibitor, while ghrelin and obestatin probably do not control oocyte maturation. The ability of PD98059 to modify the effect of hormones on oocyte maturation and on MAPK expression suggests possible interference of hormones and MAPK-dependent intracellular mechanisms in oocytes. However, no influence of hormones on MAPK and lack of association between action of hormones and PD98059 on MAPK and meiosis suggest that MAPK is probably not a mediator of effect of IGF-I, leptin, ghrelin and obestatin on porcine oocyte nuclear maturation. Keywords: leptin, ghrelin, obestatin, MAP kinase, oocyte Implication These data demonstrated the involvement of metabolic hormones and mitogen-activated protein kinase (MAPK)-dependent intracellular mechanisms in the control of oocyte nuclear maturation. This expands the existing knowledge conc...

Abstract:The aim of the present study was to examine the possible role of steroid hormones and insulin-like growth factor 1 (IGF-I) in the control of human growth and obesity. We measured plasma level of progesterone, testosterone, estradiol and IGF-I in 301 young women at different stages of their ovarian cycle, and compared them to the standard morphometric indexes of their growth and obesity -body height, body weight, abdomen circumstance and waist to hip ratio (WHR). The ovarian cycle-dependent changes in plasma progesterone and estradiol, but not in testosterone and IGF-I level were found. Young women with higher body height had significantly higher plasma level of estradiol, testosterone and IGF-I, but not of progesterone, compared to subjects with lower body height in both follicular and luteal phases of the ovarian cycle. Subjects with a higher body weight had signifi cantly higher plasma estradiol and progesterone, but not testosterone and IGF-I than subjects with lower body weight in both follicular and luteal phases of ovarian cycle. Women with a higher abdomen circumference had signifi cantly lower plasma estradiol, but not the other hormones than the subjects with lower abdomen circumference. Women with higher WHR index had signifi cantly higher plasma level of estradiol, but not other hormones than subjects with lower WHR index in both follicular and luteal phases of ovarian cycle. The present observations suggests: (1) that luteal phase of the women ovarian cycle is characterised by a dramatically increase in both progesterone and estradiol, but not in testosterone and IGF-I release, (2) that in human females growth can be up-regulated by testosterone, estradiol and IGF-I, but not by progesterone, (3) that body mass can be up-regulated by progesterone and estradiol, but not by testosterone or IGF-I, and (4) that women obesity (high WHR, but not abdomen circumference) can be promoted by estradiol, but not by other steroid hormones or Fig. 4, Ref. 45). Full Text in PDF www.elis.sk.

The intensity of symptoms on infested leaves was also different depending on treatments and years. The average biological activity was 82.4% in plots receiving releases of T. pyri and 58.8% in plots treated with Polysulphide-Ca.

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It was previously documented that cyclic AMP (cAMP)-dependent intracellular mechanisms can be involved in control of reproductive processes, and pharmacological regulators of these mechanisms could be practically used to improve rabbit fertility (Sirotkin et al. 2008; Sirotkin et al. 2010a; Chrenek et al. 2012). Changes in fertility could be due to changes in oviductal functions. The aim of our study was to examine the involvement of cAMP-dependent intracellular mechanisms in control of oviductal cell functions, in particular the influence of dbcAMP, a cAMP agonistic analogue, on proliferation and apoptosis of cultured oviductal cells. For this purpose, we compared the expression of markers of proliferation (PCNA, cyclin B1) and apoptosis (bax and bcl-2) in the oviduct epithelial cells isolated from rabbits, whose ovarian and oviductal cycle was induced by gonadotropins alone or in combination with dbcAMP (50 microg/animal) by using immunocytochemistry. It was observed that dbcAMP administration caused an increase in the proportion of cells containing PCNA, but not cyclin B1, bax or bcl-2. Higher expression of PCNA, but not cyclin B1, in the dbcAMP-treated group suggests that the dbcAMP administration can stimulate oviductal cell proliferation, probably promoting transition of cells from G0 to G1 and S-phase of the cell cycle. No influence of dbcAMP administration on regulators and markers of apoptosis (pro-apoptotic - bax and anti-apoptotic - bcl-2) suggests that dbcAMP is probably not involved in the control of apoptosis in rabbit oviduct epithelial cells. The involvement of cAMP-dependent intracellular mechanisms in control of oviduct functions is assumed in this study. This is the first demonstration that dbcAMP can stimulate proliferation of the oviduct epithelial cells without influencing their apoptosis.