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Glycogen distribution in porcine Fallopian tubes epithelium during the estrus cycle

100%

Gregoraszczuk E. L., Cala M., WitkowskA E.

Folia Biologica

2000

vol. 48

issue 3-4

85-90

Histochemical features of two different parts of the porcine Fallopian tube have been studied, with special reference to cyclic changes in the distribution of glycogen particles. Porcine Fallopian tubes were obtained from a local slaughterhouse. Slides were studied under light microscopy utilising histological and histochemical techniques. The most striking feature during the periovulatory stage of the estrus cycle was the occurrence of glycogen granules in the apical cytoplasm of epithelial cells in both the ampulla and isthmus of the Fallopian tubes. In the isthmus, cells containing numerous granules of polysaccharides aggregated into areas of different sizes were noted after ovulation. During the midluteal phase their number was minimal or were even absent. In the ampula typical extrusion of secretory granules and nuclei protruding into the tubal lumen was visible after ovulation. In the luteal phase a lot of nuclei protruded into the tubal lumen and some free in the lumen were noted. It is possible that glycogen in the preovulatory stage functions as a source of energy for ciliary movement and as a nourishment for the ovum. In the isthmus large number of aggregated glycogen particles was observed also after ovulation. In this stage of the cycle, numerous granules of polysaccharide aggregated in isthmus epithelium could be the major energy source for embriogenesis when the embryo travels down the Fallopian tubes, during the early cleavage stage.

Placental lactogen not growth hormone and prolactin regulates secretion of progesterone in vitro by the 40-45 day ovine corpus luteum of pregnancy

88%

Wierzchos E., Gregoraszczuk E. L., Zieba D., Murawski M., Gertler A.

Folia Biologica

2000

vol. 48

issue 1-2

19-24

The study was designed to compare the direct effect of three prolactin-like hormones on steroidogenesis of ovine luteal cells collected at day 40-45 of pregnancy. 100 ng/ml of ovine placental lactogen or 100 ng/ml of ovine growth hormone or 100 ng/ml of ovine prolactin were added to the media of luteal cell cultures. After 48 h incubation, all cultures were terminated and the media were frozen until further steroid analysis. To determine to what extent growth hormone (GH), prolactin (PRL) and lactogen (PL) regulate the activity of 3$-HSD, an enzyme involved in progesterone synthesis, the classical steroidal competitive inhibitor of 3$-HSD trilostane, was investigated for its effects on basal and GH-, PRL-, and PL-stimulated progesterone biosynthesis since there is a possibility that the luteotropic effect of these hormones are mediated via 3$-HSD. oPL resulted in an increase of progesterone secretion in a statistically significant manner, while GH or PRL had no effect on progesterone secretion. A decrease in progesterone secretion as an effect of 100 mM trilostane was observed in all culture types. An explanation for the luteotropic effect of PL and the lack of this effect for GH is that the GH receptor associates with a different molecule within the ovarian tissue and forms a heterodimeric receptor for PL, and the possibility that physiological effects of native oPL may be mediated through its binding to specific PL receptors, which have low affinities for oGH and oPRL.

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2 Folia Biologica

2 2000

2 Gregoraszczuk E. L.

1 Cala M.

1 Gertler A.

1 Murawski M.

1 Wierzchos E.

1 WitkowskA E.

1 Zieba D.

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Glycogen distribution in porcine Fallopian tubes epithelium during the estrus cycle

Placental lactogen not growth hormone and prolactin regulates secretion of progesterone in vitro by the 40-45 day ovine corpus luteum of pregnancy