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K H Wright

Publications and source records attributed to K H Wright.

At least 37 records · Page 2Linked to original sources
PubMed1977

The influence of ovarian denervation and nerve stimulation on ovarian contractions.

Two techniques were used to study the neuromuscular control of rabbit ovarian contractions. First, the ovary was denervated by stripping its artery. Spontaneous contractions were noted, as was a normal response to exogenously administered adrenergic agents. Second, the ovarian nerves were electrically stimulated in an in vitro perfused ovary system. Inhibition of ovarian contractions was noted, and the additive effects with adrenergic agents suggested a betamimetic effect of nerve stimulation in the estrous rabbit. After administration of exogenous human chorionic gonadotropin, the response was reversed. The significance of the contribution of a neuromuscular mechanism to the control of ovulation is discussed.

Animals↗
PubMed1976

In vitro studies of ovulation in the perfused rabbit ovary.

A system has been developed for the perfusion of the rabbit ovary in vitro. At laparotomy, the ovarian artery is cannulated and perfused with M 199 tissue culture medium containing insulin and heparin, then removed with its vascular pedicle intact. Perfusion at 37 degrees C is maintained by using a capillary oxygenator and Buchler roller pump. The functional integrity of the perfused ovary is confirmed by serial determinations of the perfusate pH, glucose and lactate concentrations, and by ovarian histology. This in vitro model was used to study the mechanism of ovulation. One group of isolated rabbits received human chorionic gonadotropin (50 IU, intravenously) and, 8 hours later, one ovary was removed and perfused; the contralateral ovary remained in situ, serving as an in vivo control. Serial observations for follicle development and rupture were made over the subsequent 7-hour interval. The occurrence of ovulation in vitro was documented by time-lapse photography. In each animal, comparisons made between the in vitro and in vivo ovary indicated that the rate and time of follicle maturation and ovulation were comparable. Ovulation occurred between 10 and 15 hours after administration of human chorionic gonadotropin in both preparations.

Animals↗
PubMed1976

The effects of cholinergic agents on ovarian contractility in the rabbit.

Cholinergic nerves have been recognized in the ovaries of several species. Smooth muscle fibers have also been demonstrated within the ovary, and it has been suggested that these elements are involved in the ovulatory process. Ovarian contractility was investigated in 49 ovaries from 25 rabbits in in vivo and in vitro systems and correlated with the time of hCG-induced ovulation. Effects of 6 cholinergic drugs on ovarian contractility were recorded at various intervals from 6 to 20 hours after administration of hCG. Cholinergic agents were administered via the abdominal aorta in the in vivo preparations and added to the bath for in vitro studies. In general, acetylcholine, bethanechol and pilocarpine exerted variable effects. Atropine depressed ovarian contractile activity. No definitive pattern of altered sensitivity to cholinergic drugs could be identified as the time of ovulation was approached; however, a relationship was observed between the amount of cholinergic drug administered and effects on ovarian contractions.

Acetylcholine↗
PubMed1976

Studies of rabbit ovarian contractility using chronically implanted transducers.

A chronically implanted, highly sensitive force transducer was used to study ovarian contractions in the rabbit. The transducer is implanted into the medulla of the ovary through its long axis. The leads are then drawn through the abdominal wall and directed subcutaneously to the back of the neck. The miniature pin connector is fixed into place beneath the skin to facilitate accessibility for repeated recordings, obviating the necessity for anesthesia or serial laparotomies. Intraovarian transducers were implanted in isolated rabbits. Serial recordings of ovarian contractions were made at weekly intervals for 3 weeks, following which ovulation was induced with 100 IU of human chorionic gonadotropin (HCG). Extended recordings were made from 3 through 13 hours after HCG administration to six animals. Recordings revealed increased ovarian contractile activity beginning just before the anticipated time of ovulation. The observations support those of previous acute experiments and demonstrate a relationship between ovarian contractile activity and the process of follicle rupture.

Animals↗
PubMed1975

The effect of indomethacin of HMG-HCG induced ovulation in the phesus monkey.

The investigation was designed to study the influence of indomethacin on gonadotropin induced ovulation in the rhesus monkey. Six mature female monkeys were treated with HMG-HCG for at least 2 control ovulatory cycles at dosage levels adjusted to induced ovulation while avoiding superovulation. Ovulation was confirmed by observation of the ovaries for fresh ovulation points at laparotomy. Following establishment of an appropriate dosage schedule, treatment was begun with indomethacin (5 mg/kg/day) starting 5 days prior to HCG and continuing to the time of laparotomy. In a second treatment cycle, indomethacin was administered at a dose of 5 mg/kg b.i.d. together with the established dose of HMG-HCG. Ovarian inspection was carried out as in the control cycles. Venous blood was obtained on treatment days 4, 7, 10 and 11 for determination of serum estrone, estradiol and progesterone. Indomethacin administration resulted in ovulation inhibition at a dose of 10 mg/kg/day when ovulation inducing doses of gonadotropins were administered. Peripheral blood steroid levels suggest that follicle maturation and estrogen production was unimparied by indomethacin. These findings indicate that the ovarian synthesis of prostaglandin may be essential in the process of ovulation.

Animals↗
PubMed1975

Effectiveness of prostaglandin f 2 alpha in restoration of HMG-HCG induced ovulation in indomethacin-treated rhesus monkeys.

Six mature female rhesus monkeys were treated with HMG-HCG in control cycles at doses adjusted to induce ovulation while avoiding superovulation. Occurrence of ovulation was determined by observation of fresh ovulation points at laparotomy 48 to 120 hours following HCG. In subsequent cycles animals were treated with indomethacin (treatment days 4 through 10) together with the established dose of HMG-HCG. In 8 cycles indomethacin 5 mg/kg was given i.m. once daily; in 9 cycles 10 mg/kg i.m. was administered in 2 divided doses. Following this, PGF2alpha (3 mg t.i.d. s.c.) was administered for 3 days together with indomethacin 10 mg/kg and HMG-HCG, beginning on the day prior to HCG. Determinations of progesterone were performed by RIA on treatment days 4, 7, 10, and 11. Eleven of the 13 control cycles were ovulatory. With indomethacin 5 mg/kg/day, 5 of 8 cycles were ovulatory but ovulation was delayed in 2 instances. Of 9 cycles using indomethacin 10 mg/kg/day only 1 was ovulatory. When PGF2alpha was administered in susequent cycles along with indomethacin (10 mg/kg) and HMG-HCG, ovulation occurred in 13 of 19 cycles. These data suggest that local ovarian PGF2alpha may be essential in the mechanics of follicle rupture in gonadotropin-treated rhesus monkeys.

Animals↗
PubMed1975

Lack of effect of ovarian denervation on ovulation and pregnancy in the rabbit.

Following unilateral ovarian denervation by ovarian artery stripping in female rabbits, ovulation and pregnancy were achieved within 3 days of denervation. Three weeks later, at repeat laparotomy, ovarian dimensions and the numbers of corpora lutea and pregnancies were noted. Fluorescent histochemical studies confirmed complete adrenergic denervation in five of the rabbits' ovaries. There was no significant difference in ovarian dimensions, numbers of corpora lutea and pregnancies, or the excess of corpora lutea over implantations when the intact control side was compared with the denervated side. The control ovaries demonstrated an average of 5 corpora lutea/ovary and an average of 3.4 conceptuses in the adjacent uterine horn, while the numbers on the denervated side were 5 and 3.2, respectively. Although these findings demonstrate that central neural efferent control is not essential for the occurrence of pregnancy after mating in the rabbit, the potential significance of ovarian neuromuscular mechanisms in these functions is discussed, and future studies are suggested.

Animals↗
PubMed1975

Selective ovarian sympathectomy in the rabbit.

Evidence implicates the ovarian nerves in the regulation of hormonal and ovulatory functions. A technique for selectively denervating the in situ rabbit ovary is therefore of considerable investigative value. The ovarian artery was stripped of its adventitia and nerve bundles. Three weeks later, fluorescent histochemistry confirmed the complete absence of adrenergic nerves in the vessel walls and ovarian stroma of the experimental ovary, as compared to the abundant fluorescent structures present in the contralateral control ovary. The surgically treated ovaries demonstrated no significant ischemic or trophic change on gross and routine histologic examination.

Animals↗
PubMed1975

Studies on the function of the denervated rabbit ovary: human chorionic gonadotropin-induced ovulation.

The described method for selective sympathetic denervation of the in vivo rabbit ovary involved stripping the ovarian artery of its nerve bundles and adventitial tissue. The ovary was then entirely free of fluorescent-staining adrenergic nerves. This technique was used to study the effects of ovarian denervation on HCG-induced ovulation. After HCG was administered to 22 rabbits which had previously undergone unilateral ovarian denervation, the ovaries were observed for follicular maturation and rupture. Control ovaries demonstrated a mean of 5.6 stimulated follicles/ovary; denervated ovaries had a mean of 5.4. An average of 3.5 follicles/control ovary ruptured; an average of 3.1 follicles/denervated ovary ruptured. Furthermore, the time course of ovulation after HCG did not differ between denervated and intact ovaries. These results indicate that HCG-induced ovulation in the rabbit is not interrupted by ovarian denervation.

Animals↗
PubMed1975

Influence of estrogen and progesterone treatment on ovarian contractility in the monkey.

Five female rhesus monkeys were treated with natural estrogens, 5 mg/day for three weeks, after which ovarian contractility was studied in vitro in one of the ovaries. Estrogen treatment was followed by progesterone, 25 mg/day for three weeks, after which the contractility of the remaining ovary was similarly measured. Responses to autonomic agents and prostaglandins were studied in both groups. Spontaneous ovarian contractility and ovarian contractile responsiveness to prostaglandins and norepinephrine were found to be enhanced after progesterone treatment. Cholinergic agonists had a stimulatory effect after progesterone and an inhibitory effect after estrogens. Our results suggest that ovarian contractile responsiveness is modified by the local steroid environment, perhaps through intracellular changes in cyclic AMP.

Animals↗