• Development and Reproduction
• /
• v.13 no.2
• /
• pp.79-87
• /
• 2009

Due to its well-known function in parturition and milk ejection, oxytocin (OT) has been considered as a 'female neurohypophyseal hormone'. Recent studies, however, clearly indicate that OT has some local roles in male reproduction via both central and peripheral routes. In experimental rodents, OT is released within distinct brain regions in response to social stimuli, and the brain OT receptor (OTR) mediated actions were strongly involved in the regulation of a variety of male behaviors such as mating-associated behaviors. In particular, OT and/or OTR knockout mice provide important clues about the molecular regulatory mechanism of the socio-sexual behaviors. Several lines of evidence also show that OT is synthesized within rodents testis, epididymis and prostate, and the presence of OTRs in these organs. In rodent testes, OT might have a role in the modulation of steroidogenesis via stimulation of the conversion of testosterone (T) to dihydrotestosterone (DHT) by 5alpha-reductase. Similar effects of OT on this androgen conversion were observed in epididymis and prostate suggesting the OT's modulatory role, such as contractility induction, in these androgen-dependent organs. In this context, further investigations on the OT's role in male CNS and reproductive organs are likely to provide better understanding on the complex socio-sexual behaviors and a platform for development of therapeutics to treat some psychological and/or andrological problems.

• Korean Journal of Veterinary Research
• /
• v.36 no.1
• /
• pp.83-91
• /
• 1996

Activation of $K^+$ channels induces relaxation of smooth muscles by reducing electrical excitability and cytosolic free $Ca^{2+}$ level. ${\beta}$-adrenergic agonist isoproterenol is known to induce relaxation of the uterine smooth muscle by membrane hyperpolarization and $K^+$ efflux. Recently it is suggested that the activity of $Ca^{2+}$-activated $K^+$ channel was increased by isoproterenol in the uterine myocytes isolated from myometrium of the pregnant rat. However, the type of $K^+$ channel mediating the relaxant effect of isopreterenol in the tissue level has not yet studied. In this work, we investigated the type of $K^+$ channels involved in the isoproterenol-induced relaxation of uterine smooth muscle by measuring the integrated insometric tension of the estrogen-treated isolated nonpregnant rat uterus. Contraction of uterine tissue was induced by oxytocin (0.2nM, 2~3 contractions/min) or high KCl(20~80mM). The result are as follows : 1. Isoproterenol($10^{-10}{\sim}10^{-4}M$) inhibited oxytocin-induced contraction of isolated rat uterus($EC_{50}=1.17{\times}10^{-10}M$). 2. Isoproterenol($10^{-10}{\sim}10^{-4}M$) effectively inhibited uterine contraction induced by low KCl(20~40mM) but little those induced by high KCl(60~80mM). 3. Relaxant effect of isoproterenol($10^{-10}{\sim}10^{-4}M$) on 0.2nM oxytocin-induced contraction was effectively reduced by 4-aminopyridine(3, 10mM) but little by TEA(10~30mM), $Ba^{2+}$($1{\sim}30{\mu}M$) and glibenclamide($100{\mu}M$). Our data suggest that the relaxant effect of isoproterenol is mediated by the $K^+$ channel(s) which can be blocked by 4-aminopyridine.

• Proceedings of the KSAR Conference
• /
• 2004.06a
• /
• pp.228-228
• /
• 2004

Interferon-tau (IFN-τ) is the primary agent responsible for maternal recognition of pregnancy in cattle. Bovine embryos begine to express IFN-τ as the blastocyst forms. Pregnancy recognition in ruminants occurs when IFN-τ from the trophoblast prevents the increase of oxytocin receptors, disrupting luteolytic pulses of prostaglandin (PG) F2a by oxytocin. The expression of IFN-τ is strongly associated with the degree of methylation of the CpG islands in promoter region. (omitted)

• THE JOURNAL OF KOREAN ORIENTAL ONCOLOGY
• /
• v.1 no.1
• /
• pp.213-230
• /
• 1995

The present work was done to investigate the pharmacological effectiveness of Guichoolpajing-Tang and Gamiguichoolpajing-Tang. The extracted water of those two prescription were administered to experimintal animals and determined analgesic, anti-pyretic, anti-inflammatory effects and effects on intravascular coagulation, spontaneous morements of the isolated rat uterus, the uterine contracion induced by oxytocin or $PGF_{20}$, lifespan of mice implanted intraperitoneally with Sarcoma 180. The following results were obtained. 1) The extracted water of Guichoolpajing-Tang and Gamiguichoolpajing-Tang were revealed significant analgesic effect. 2) The extracted water of Guichoolpajing-Tang and Gamiguichoolpajing-Tang showed anti-pyretic effect. 3) The extracted water of Guichoolpajing-tang and Gamiguichoolpajing-Tang showed anti-inflammatory effect. Especially, the extracted water of Gamiguichoolpajing-Tang showed more significant dffect than another. 4) Concerning the degree of concentration of FDP, Gamiguichoolpajing-Tang treated groups tevealed significant decreases. 5) The extracted water of both prescriptions revealed uterus relaxation on the spontaneous movement of the isolated rat uterus and showed uterine contraction induced by oxytocin or $PDF_{2}$. Especially Guichoolpajing-Tang showed more significant effect than another. 6) The extracted water of both prescription both prescriptions showed effect on lifespan of mice implanted intraperitoneally with Sarcoma 180.

• The Korean Journal of Physiology
• /
• v.20 no.2
• /
• pp.199-208
• /
• 1986

The effects of $Mg^{++}$ upon the spontaneous contraction activated by 1 IU/l oxytocin were studied in the isolated rat uterine muscle. Longitudinal muscle strips u·ere prepared from the rat uteri at the estrous stage. All experiments were performed in tris-buffered Tyrode solution which was aerated with 100% $O_2$ and kept at $35^{\circ}C$. The results obtained were as follows: 1) In the uterine strips contracting spontaneously, as $Mg^{++}$ concentration increased in the Tyrode solution the amplitude of peak tension decreased in all the experimental solutions containing the various concentrations of $Ca^{++}\;(0.5{\sim}4 mM)$. And the amplitude of peak tension increased in inverse proportion to the $[Mg^{++}]/[Ca^{++}]\; ratio$. It is suggested that the tension-lowering effect of $Mg^{++}$ would be developed through decreasing intracellular ionized free calcium ion concentration by uncertain mechanism. 2) The frequency of the uterine contraction activated by oxytocin increased as the $[Mg^{++}]/[Ca^{++}]\;ratio$ ratio increased up to 1/2, but the frequency decreased above this ratio. It is speculated that $Mg^{++}$ would influence the excitability control action of $Ca^{++}$.

• Women's Health Nursing
• /
• v.11 no.3
• /
• pp.202-208
• /
• 2005

Purpose: This study was conducted to discover the related factors of neonatal suckling in the initiation of breastfeeding in primiparous mothers and to provide basic data for promoting nursing intervention strategies to improve the practice of breastfeeding. Method: The subjects of this study were 71 primiparous mothers who had normal vaginal deliveries at one obstetric hospital in P metropolitan city and one delivery center in J city. The collected data was analyzed using the SPSS program. Result: The average IBFAT(Infant Breastfeeding Assessment Tool) score was 9.6$\pm$2.3. The general characteristics studied that had a significant influence on neonatal suckling in the initiation of breastfeeding were the place of delivery (ex: Hospital, Postnatal Unit), whether oxytocin was used, no usage of analgesic medication, amount of satisfaction after the first breastfeeding weight of the newborns and the Apgar score at one minute. Conclusions: A higher IBFAT score was related to primiparous mothers who had a hospital delivery, received oxytocin, received maternal labour analgesics, neonatal weight, Apgar score at one minute, and satisfaction after the first breastfeeding.

• Asian-Australasian Journal of Animal Sciences
• /
• v.30 no.6
• /
• pp.878-885
• /
• 2017

Objective: Glucose is an essential fuel in the energy metabolism and synthesis pathways of all mammalian cells. In lactating animals, glucose is the major precursor for lactose and is a substrate for the synthesis of milk proteins and fat in mammary secretory (alveolar) epithelial cells. However, clear utilization of glucose in mammary cells during lactogenesis is still unknown, due to the lack of in vitro analyzing models. Therefore, the objective of this study was to test the reliability of the mammary alveolar (MAC-T) cell as an in vitro study model for glucose metabolism and lactating system. Methods: Undifferentiated MAC-T cells were cultured in three types of Dulbecco's modified Eagle's medium with varying levels of glucose (no-glucose: 0 g/L, low-glucose: 1 g/L, and high-glucose: 4.5 g/L) for 8 d, after which differentiation to casein secretion was induced. Cell proliferation and expression levels of apoptotic genes, Insulin like growth factor-1 (IGF1) receptor, oxytocin receptor, ${\alpha}S1$, ${\alpha}S2$, and ${\beta}$ casein genes were analyzed at 1, 2, 4, and 8 d after differentiation. Results: The proliferation of MAC-T cells with high-glucose treatment was seen to be significantly higher. Expression of apoptotic genes was not affected in any group. However, expression levels of the mammary development related gene (IGF1 receptor) and lactation related gene (oxytocin receptor) were significantly higher in the low-glucose group. Expressions of ${\alpha}S1-casein$, ${\alpha}S2-casein$, and ${\beta}-casein$ were also higher in the low-glucose treated group as compared to that in the no-glucose and high-glucose groups. Conclusion: The results demonstrated that although a high-glucose environment increases cell proliferation in MAC-T cells, a low-glucose treatment to MAC-T cells induces higher expression of casein genes. Our results suggest that the MAC-T cells may be used as an in vitro model to analyze mammary cell development and lactation connected with precise biological effects.

• The Korean Journal of Pharmacology
• /
• v.30 no.2
• /
• pp.191-203
• /
• 1994

$K^+$ channel openers (KCOs) are known to have a wide range of effects by opening the $K^+$ channel in plasma membranes of various smooth muscles, cardiac muscle and pancreatic ${\beta}-cell$. In the present study, we investigated the effects of 5 types of KCOs, cromakalim, RP49356, pinacidil, nicorandil and diazoxide on the contractility of isolated rat uterus. All KCOs tested inhibited the uterine contraction induced by 0.2 nM oxytocin in a dose-dependent manner. Individual KCO and its $pD_2$ values were cromakalim 6.5, RP49356 6.3, pinacidil 5.92, nicorandil 4.43 and diazoxide 4.18. The relaxant effects of KCO were inhibited by glibenclamide (0.3, 1 and $10\;{\mu}M$) with $pA_2$ values of cromakalim 6.91, RP49356 6.59, pinacidil 6.55, nicorandil 5.97 and diazoxide 6.37. In addition, the relaxant effect of cromakalim or pinacidil was antagonised by TEA, a non-selective $K^+$ channel blocker, but not by apamin. Contractions induced by low concentration of KCI (< 40 mM) were inhibited by cromakalim $(100{\mu}M)$ and nicorandil $(300{\mu}M)$, but those evoked by higher concentration (> 40 mM) of KCI were little affected. In ovariectomized rat uterus, cromakalim dose-dependently inhibited oxytocin-induced contraction and glibenclamide $(10{\mu}M)$ inhibited the relaxant effect of cromakalim with $pD_2$ and $K_B$ values of 7.48 and $1.26{\times}10^{-7}M$, respectively. In estrogen-primed rat uterus, these values were 6.51 and $1.57{\times}10^{-7}M$, respectively, indicating that the cromakalim is less effective on the estrogen-treated uterine smooth muscle. Our results suggest that the KCO-sensitive $K^+$ channels participate in the motility of uterine smooth muscle and such channels are, at least in part, under the control of estrogen. In addition, our data Indicate that the type of $K^+$ channels activated by KCO is ATP-sensitive $K^+$ channels which is blocked by glibenclamide.

• Proceedings of the Korean Society of Food Hygiene and Safety Conference
• /
• 2001.10a
• /
• pp.219-222
• /
• 2001

• Korean Journal of Pharmacognosy
• /
• v.22 no.4
• /
• pp.246-248
• /
• 1991

The methanolic extracts of forty-two medicinal plants were screened for direct effects on the isolated ileum and uterus and for anticholinergic and oxytocic effects on the respective organ preparation.