Effects of Catecholamines and Dibenamine on Ovulation in the Perfused Fowl Ovary

Transcription

1 Effects of Catecholamines and Dibenamine on Ovulation in the Perfused Fowl Ovary Tomoki HIGUCHI, Tomoki SOH, Frank HERTELENDY* and Kousaku TANAKA Faculty of Agriculture, Kyushu University, Higashi-ku, Fukuoka-shi 812 * Department of Obstetrics and Gynecology, St. Louis University School of Medicine, St. Louis, Missouri, U.S.A. (Received February 7, 1994) tion in the perfused fowl ovary were studied. Ovaries removed 16-18h before the expected ovulation time of the first (C1) or second (C2) follicle of a clutch sequence were perfused in vitro with perfusion fluid containing the compounds, Both epinephrine (10-5M) and norepinephrine (10-5M) were highly effective in inducting ovulation of either C1 or C2 follicles, at a rate of 88% and 80%, respectively, which was comparable to the efficacy of gonadotrophin treatment alone (88% and 82%). Dibenamine (10-4M) added 30min prior to gonadotrophins suppressed the ovulation of only C2 follicles (18%), while the ovulation rate in the C1 group was 57%. Anim. Sci. Technol. (JPn.) 65 (10): , 1994 Key words: fowl ovary, perfusion, catecholamines, dibenamine The physiological significance of with the preovulatory surge of LH1,6,18) catecholamines in the process of ovulation in MOUDGAL and RAZDAN17) reported that ovulation hens is suggested by the observations that the in the isolated largest follicle of the hen was injection of adrenergic antagonists, dibenamine and dibenzyline, blocks spontaneous cholamines to a culture medium, while induced by the addition of these cate- ovulation5,20). FERRANDO and NALBANDOV10) LH-induced ovulation was inhibited by their found that a local injection of dibenzyline directly into the follicular wall blocked ovulation The present study was designed to elucidate antagonists. in hens. Confirming their results with a successful induction of ovulation by either norepinephrine as well as dibenamine, an ad- the effects of catecholamines, epinephrine and epinephrine or norepinephrine, KAO and renergic antagonist, on ovulation in the NALBANDOV16) suggested that adrenergic perfused fowl ovary. neurons are involved in the ovulatory process Materials and Methods of hens and that alpha receptor sites are most important in this mechanism. In the laying Birds from a commercial hybrid egg-laying hen, catecholamines are localized primarily in stock were used. They were maintained in the theca layer with only small amounts pres- individual laying cages and were exposed to a ent in the granulosa layer and are abundant in the largest follicle1). Further, both epinephrine and norepinephrine in the largest follicle have been found to increase in coincidence 14h photoperiod. All hens selected for the study were producing clutches of more than 3 eggs, with a pause of a single day between clutches. Hens were killed 16-18h before ex- Anim. Sci. Technol. (Jpn.) 65 (10):

2 Catecholamines pected ovulation of the C1 or C2 follicle of a clutch sequence. After exposure of the abdominal cavity, the ovary was cannulated, dissected free and connected to a recycling perfusion apparatus, as described by TANAKA et al.19). Routinely, 2 separate perfusion systems containing 500ml of perfusion fluid/ovary were operated simultaneously. Epinephrine or norepinephrine (Sigma Chemical Co., St. Louis, MO, U.S.A.)(10-5 mol) was dissolved in 1ml of 0.15M NaCl and added to perfusion fluid to make 10-5M concentration of catecholamine. Dibenamine hydrocholoride (Nakarai Chemical Co., Kyoto, Japan), an antiadrenergic drug (10-4 mol) was dissolved in 0.3ml of 95% ethanol, followed by mixing with 1ml of ethylene glycol and 2ml of perfusion fluid. This solution was added to perfusion fluid to make 10-4 M concentration of the drug. The ovary was first perfused with dibenamine for 30min, and then gonadotrophins (LH 1U+FSH 1U) were added. Ovine LH (NIAMDD-oLH-22, 2.3U/ mg) and Ovine FSH (NIAMMD-oFSH-13, 15U/ on Ovulation mg) were generously provided by the National Pituitary Agency. Each of these hormones was dissolved in 0.15M NaCl to make 1U/ml 95% ethanol (0.3ml), ethylene glycol (1ml) and perfusion fluid (2ml) served as control. The significance levels for the percentage of the largest follicles ovulating were determined Results The ovulation response of the perfused ovary are shown in Table 1. When epinephrine was added to the perfusion fluid, more than 80% of either the C1 or C2 follicles ovulated. There was no statistical difference in ovulation rates between norepinephrine (70%) and gonadotrophins (88%) in the C1 group. On the other hand, the ovulation rate in response to norepinephrine (42%) in the C2 group was lower (p<0.05) than that of gonadotrophins (82%). Dibenamine suppressed gonadotrophin-induced ovulation by Table 1. The effect of catecholamines and dibenamine on ovulation in the perfused ovary 1 Hens were killed 16-18h before expected ovulation of the first (C1) or second (C2) follicle of a clutch sequence. 2 Mixture of 95% ethanol (0.3ml), ethylene glycol (1ml) and perfusion fluid (1ml) served as control. Values with different superscripts are significantly different, p<

3 HIGUCHI, SOH, HERTELENDY and TANAKA 18% only in the C2 group (p<0.01) when compared to 57% in C1 group of dibenamine. The interval between the onset of perfusion and follicular rupture was about 3-5h. In general, the follicles which failed to ovulate became atretic by 6-9h after the start of perfusion. Discussion Since no information was available for blood concentration of catecholamines at preovulation of the fowl as far as our knowledge was concerned, we employed the concentration used by MOUDGAL and RAZDAN17). The present studies demonstrate that both epinephrine and norepinephrine are highly effective in causing ovulation independently of gonadotrophins. These observations are in agreement with those of MOUDGAL and RAZDAN17). On the other blocker, appeared to suppress gonadotrophininduced ovulation of both C1 and C2 follicles, but a statistical difference was obtained only in the C2 group when compared to gonadotrophin-induced ovulation. This may be attributed to the low ovulability of the C2 follicle in general9,11,12,14). In addition to the ability of exogenous catecholamines to cause ovulation, there is evidence that the follicular content of catecholamines, chiefly norepinephrine, is elevated prior to ovulation only in the largest follicle1,18). Both adrenergic and cholinergic innervation increase with follicular maturation13). However, the mode of action of catecholamines in the process of ovulation has not yet been elucidated. FERRANDO and NALBA- NDOV10) have reported that the ovulation-blocking effect of dibenzyline can be overcome by systemic injection of LH, while locally given LH is ineffective, suggesting that LH per se may not be the ovulation-inducing hormone. Later, KAO and NALBANDOV16) demonstrated that the blocking effect of dibenzyline could not be overcome by a local injection of epinephrine, norepineophrine or LH alone. Recent studies have shown that norepinephrine enhances the responsiveness of granulosa Since in mammals catecholamines have been reported to stimulate the production of progesterone in the ovary2-4,8), and progesterone has been suggested to be the ultimate hormonal signal for the rupture of the follicle in the fowl19), there is a distinct possibility that catecholamines and progesterone act in concert to bring about ovulation in the fowl. However, there is evidence that FSH augments the action of LH to induce ovulation15). Consequently LH as well as FSH may not be rule out from the direct participation in follicle rupture. Clearly, further investigation is required before the role of catecholamines in the ovarian function, with particular reference to the normal process of ovulation, is fully understood. Acknowledgements We thank NIAMDD, Bethesda, Maryland, for the generous gift of the ovine LH and FSH used in these experiments. References 1) BAHR, J. M., L. K. RITZHAUPT, S. MCCULLOUGH, L. A. ARBOGAST and N. BEN-JONATHAN, Catecholamine content of the preovulatory follicles of the domestic hen. Biol. Reprod., 34: ) BATTISTA, P. J. and W. A. CONDON, A role for alternative pathway catecholamines in the regulation of steroidogenesis in cow luteal cells. J. Reprod. Fert., 78: ) BATTISTA, P. J., J. P. POFF, D. R. DEAVER and W. A. CONDON, Biogenic amine regulation of bovine luteal progesterone production in vivo. J. Reprod. Fert., 80: ) BATTISTA, P. J., C.E. JR. REXROAD, J. P. POFF and W. A. CONDON, Support for a physiological rose of endogenous catecholamines in the stimulation of bovine luteal progesterone production. Biol. Reprod., 41: ) BULLOCK, D. W. and A. V. NALBANDOV, Hormonal control of the hen's ovulation cycle. J. Endocrinol., 38:

4 Catecholamines 6) CHOTESANGASA, R., M. KAMIYOSHI, K. TANAKA, H. TOMOGANE and A. YOKOYAMA, Changes in catecholamine contents in ovarian follicular theca, progesterone contents in granulosa, and LH concentrations in peripheral plasma during the ovulatory cycle in the hen. Acta Endocrinol., 115: ) CHOTESANGASA, R., M. KAMIYOSHI, K. TANAKA, H. TOMOGANE and A. YOKOYAMA, Enhancement of the response of hen granulosa cells to LH with norepinephrine in vitro. Comp. Biochem. Physiol., 90C: ) CONDON, W. and D. L. BLACK, Catecholamineinduced stimulation of progesterone by the bovine corpus luteum in vitro. Biol. Reprod., 15: ) ETCHES, R. J., H. E. MACGREGOR, T. F. MORRIS and J.B. WILLIAMS, Follicular growth and maturation in the domestic hen (Gallus domesticus). J. Reprod. Fert., 67: ) FERRANDO, G. and A.V. NALBANDOV, Direct effect on the ovary of the adrenergic blocking drug dibenzyline. Endocrinology, 85: ) FRAPS, R. M. and A. DURY, Occurrence of premature ovulation in the domestic fowl following administration of progesterone. Proc. Soc. Exp. Biol. Med., 52: ) FRAPS, R. M., Egg production and fertility in poultry. in Progress in the Physiology of Farm Animals (HAMMOND, J. ed.). London: Butterworths, Vol. 2, ) GILBERT., A. B., Innervation of the ovary of the on Ovulation domestic hen. Q.J. Exp. Physiol., 54: ) JOHNSON, A. L., P. A. JOHNSON and A. VAN TIENHOVEN, Ovulatory response and plasma concentrations of luteinizing hormone and progesterone following administration of synthetic mammalian or chicken luteinizing hormone-releasing hormone relative to the first or second ovulation in the sequence of the domestic hen. Biol. Reprod., 31: ) KAMIYOSHI, M. and K. TANAKA, Augmentative effect of FSH on LH-induced ovulation in the hen. J. Reprod. Fert., 29: ) KAO, L. W. L. and A. V. NALBANDOV, The effect of antiadrenergic drugs on ovulation in hens. Endocrinology, 90: ) MOUDGAL, R. P. and M. N. RAZDAN, Induction of ovulation in vitro by LH and catecholamines Nature, 293: ) MOUDGAL, R. P. and M. N. RAZDAN, Catecholamines in ovarian follicles during the ovulatory cycle of White Leghorn hens. Br. Poult. Sci., 24: ) TANAKA, K., Z. D. LI and Y. ATAKA, Studies of ovulation in the perfused ovary of the fowl (Gallus domesticus). J. Reprod. Fert., 80: ) VAN TIENHOVEN, A., A. V. NALBANDOV and H. W. NORTON, Effect of dibenamine on progesterone-induced and "spontaneous" ovulation in the hen. Endocrinology, 54:

5 HIGUCHI, SOH, HERTELENDY and TANAKA * Department of Obstetrics and Gynecology, St. Louis University School of Medicine, St. Louis, Missouri, U.S.A.