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Effect of prolactin on ovarian steroidogenesis

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Dusza, L,: Effect of prolactin on ovarian steroidogenesis. Acta physiol, pol., 1989, 40 (1): 74-84. This review summarizes evidence that prolactin (PRL) is involved directly in the regulation of ovarian steroidogenesis. The scope of this paper will be limited to two areas. The first area involves the regulation of the corpus iutieum function and the second the effect of PRL on steroidogenesis during the follicular phase of the oestrous cycle. Cyclic changes of plasma PRL levels and the ovarian receptors which bind PRL have been observed during the oestrous cycle of domestic animals. The luteotropic effect of PRL and its failure is also presented, PRL may exert a physiological effect on follicle steroidogenesis hut its effect depends on the level of follicle maturation,. The effect of PRL treatment on estrogen production by follicular cells in vivo and in vitro was studied. The results of many papers indicate suppression of estrogen secretion by the direct action of PRL at the ovarian level. However, there is abundant evidence, that PRL is involved directly in regulation of ovarian steroidogenesis, the precise mechanism remains to be discovered.
The aim of this study was to examine the effect of experimental hyperprolactinemia on the sterological parameters of porcine adrenal cortex. In cyclic sows, after preovulatory luteinizing hormone (LH) peak, porcine prolactin (PRL, 0.3 mg) or saline were administered iv. for 48 h at 2 h intervals. Next sows were slaughtered and adrenal glands were dissected. Stereological analysis of the left adrenal gland did not reveal any significant differences between control and PRL-treated sows. Experimental hyperprolactinemia did not affect the volume of particular cortical zones, the number and the volume of adrenocortical cells or the average volume of their cell nuclei. Moreover, we present for the first time a detailed stereological description of adrenal cortex in sows.
Human food and animal feed may contain phytoestrogens. These plant compounds possess a chemical structure and biological activity similar to animal estrogens. With regard to the important role of estrogens in males, it is necessary to extend knowledge pertaining to the influence of phytoestrogens on the male reproductive tract. These chemicals may affect the hypothalamic-pituitary-testis axis, controlling functions of the reproductive tract. The results showed in this review indicate that, especially in high doses, the phytoestrogens alter functions of hypothalamus, pituitary gland and testis. These effects depend on species, kind and treatment level of phytoestrogens, length of exposure as well as on the means of administration.
Biolactin-2 preparation containing 5.0 mg of porcine prolactin (pPRL) purified from porcine pituitaries was used to stimulate lactation in sows with periparturient agalactia and in healthy primiparous and multiparous sows. Immunological activity of Biolactin-2 approached that of the PRL standard. It was found that a single intramuscular injection of Biolactin-2 effectively stimulates milk ejection in sows with mastitis-metritis-agalactia syndrom (MMA). Performance of piglets treated with a single or double dose of Biolactin-2 and as well as that of healthy ones was similar. A single administration of Biolactin-2 to healthy primiparous sows on the 1st day after farrowing significantly increased daily body gains of their litter in the first two weeks of life. This effect was not observed in multiparous sows.
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