Demonstration of mRNAs for oxytocin and prolactin in porcine granulosa and luteal cells

Abstract

The relative levels of mRNAs for relaxin, prolactin, inhibin and oxytocin have been measured in porcine granulosa as well as luteal cells by hybridisation to single-stranded synthetic DNA. The likelihood of a paracrme function of oxytocm and prolactin in the porcine ovary was inferred from the in vitro effects of both hormones on progesterone secretion of ovarian cells. Both hormones were found to inhibit progesterone secretion of luteal cells. In contrast. only prolactin but not oxytocin stimulated progesterone secretion in granulosa cells. ProlactinmRNA Hybridization

Luteinising hormone receptor kinetic and LH-induced prostaglandin production throughout the oestrous cycle in porcine endometrium

“…Although the ovaries are the main source of oxytocin during luteolysis in ruminants [32], the role of ovarian oxytocin in pigs is still unclear. Since the concentration of oxytocin in porcine corpora lutea is many times lower than in ovine and bovine corpus luteum, and its level is maximal during the early luteal phase [6,29] it is thought that oxytocin may play a role as an intraovarian mediator necessary for the control of steroidogenesis [9,14,30] or corpora lutea development [6,29]. Einspannier et al [10] [12].…”

Effects of prolactin on estrogen, cAMP and oxytocin secretion by porcine granulosa cells in vitro

“…Aromatase activity in isolated hen ovarian follicles (Zadworny et al, 1989) and rat granulosa cells (Dorrington and Gore-Langton, 1982;Wang and Chan, 1982;Gitay-Goren et al, 1989 a,b; Krasnow et al, 1990) was also inhibited. In other reports, PRL stimulated progesterone production by rat (Wang and Chan, 1982) and porcine (Einspanier et al, 1986) granulosa cell cultures.…”

“…Enhanced progesterone output was observed after PRL treatment in human corpus luteum slices in culture (Hunter, 1989). In other in vitro experiments PRL either had no effect on porcine luteal cell progesterone production (Gregoraszczuk, 1985) or it was inhibitory (Grazul, 1985;Einspanier et al, 1986 (Guraya, 1985;Hansel and Dowd, 1986;Richards and Hedin, 1988;Tsafriri, 1988;Wathes, 1989). There is little information concerning PRL's influence on the non-steroidal ovarian substances.…”

Effect of intra-ovarian infusion of oxytocin on plasma progesterone concentrations in pregnant ewes

“…These results are in agreement with our earlier study on oxytocin receptors in sheep (Sernia et ai, 1989). However, there are reports in pigs (Einspanier et al, 1986;Przala et ai, 1986a, b;Pitzel et al, 1988Pitzel et al, , 1990, cattle (Schams, 1987(Schams, , 1989 and women (Tan et al, 1982b;Bennegard et ai, 1987) which, while supporting an inhibitory role, shows oxytocin effects in the nonpregnant condition. These obser¬ vations need to be reconciled with the comparable studies by Richardson & Masson (1985), Duncan et ai (1961) and Gilbert et al (1989), which show no oxytocin effect on progesterone secretion.…”