Laparoscopic ovariectomy in standing cows

The main objective of this study was to evaluate laparoscopic ovariectomy and to develop an optimal surgical technique for this procedure in standing cattle.Eight cows underwent laparoscopic ovariectomy. In two cows, a bilateral flank approach was used and in six cows, both ovaries were removed via a left flank approach.An important prerequisite for ensuring sufficient intrabdominal space for instrumentation, optimal endoscopic orientation and easy access to the ovaries and uterus was withholding feed for at least 36 h prior to surgery. The cows were sedated with xylazine and the portal sites infiltrated with lidocaine. The portal for the laparoscope was at the ventral angle of the left paralumbar fossa, approximately 10 cm cranioventral to the tuber coxae. The instruments were inserted through two portals approximately 20 cm and 30 cm ventral to the tuber coxae. After abdominal insufflation with carbon dioxide, the left ovary was grasped and local anesthetic was injected into the mesovarium and mesosalpinx. The mesovarium was transected using bipolar cauterization and the ovary removed through an extended instrument portal. The right ovary was removed in the same way. The incisions were closed with single interrupted absorbable sutures in the musculature and single interrupted non-absorbable sutures in the skin. The procedure lasted 120–150 min.Bilateral laparoscopic ovariectomy via left flank approach in standing cows is feasible. This procedure involves special instrumentation, but is minimally invasive and allows optimal visualization of the ovaries and uterus.     

Laparoscopic ovariectomy in standing donkeys by using a new instrument

Bilateral laparoscopic ovariectomy was performed in six female donkeys. Laparoscopic ovariectomy was performed in standing position by using a new laparoscopic instrument which was developed by the authors. We used the instrument for isolation, coagulation and cutting of mesovarium. One laparoscope portal and two instrument portals were located in each paralumbar fossa. The ovary was removed through an enlarged second portal. The contralateral ovary was removed through the opposite paralumbar fossa. Hemostasis, coagulation and cutting of the mesovarium were achieved successfully using the new laparoscopic instrument. The time required for removal of each ovary was between 2 and 4 min (average 2.8 min). While the total time of unilateral ovariectomy was between 10 and 15 min (average 12 min). No additional ligature was required in all operations. There was no complication, hemorrhage or oozing of blood from the mesovarium during or after the operations. In conclusion, laparoscopic ovariectomy in donkeys by using this new instrument was safe and effective. The new instrument reduced the time of operation and provided a viable hemostasis and coagulation for blood vessels within the mesovarium. Also cutting of the mesovarium was very easy.     

腹腔镜下联合垂体后叶素行卵巢巧克力囊肿剥除术的 临床分析

目的:探讨腹腔镜下联合垂体后叶素行卵巢巧克力囊肿剥除的可行性及治疗效果。方法:腹腔镜下治疗60例卵巢巧克力囊肿患者(A组),予垂体后叶素12μ注射于子宫体及卵巢系膜,再行囊肿剥除手术,并与腹腔镜下常规行卵巢巧克力囊肿剥除术的患者60例(B组)比较,分析手术时间、术中出血量、术后体温恢复正常时间、术后排气时间及术后住院时间等临床指标。结果:A组手术时间和术中出血量明显少于B组,两组比较差异有显著性(P<0.01);A组术后体温恢复正常时间小于B组,两组比较差异有统计学意义(P<0.05);A、B两组术后排气时间及术后住院时间差异无统计学意义(P>0.05)。结论:腹腔镜下联合应用垂体后叶素行卵巢巧克力囊肿剥除术可有效的减少术中出血,缩短手术操作时间,进而保护卵巢功能。     

Follicle stimulating hormone secretion and compensatory ovarian hypertrophy in prepubertal ewes

A study was conducted to determine the effect of unilateral ovariectomy (ULO) on follicle stimulating hormone (FSH) secretion and compensatory ovarian hypertrophy in prepubertal ewes. Thirty-three ewe lambs were allotted according to age and weight to a control (C) or ULO group. In the C group, a sham ovariectomy was performed on day 0 and both ovaries were removed on day 7. In the ULO group, one ovary was removed on day 0 and the remaining ovary was removed on day 7. Blood samples were collected from the jugular vein via venipuncture at 0, 6, 12 and 24 hours after the time of sham surgery or ULO (day 0). Subsequent samples were collected daily until day 7, and all samples were assayed for FSH and LH. Unilateral ovariectomy increased (P<0.01) ovarian weight and follicular fluid weight; however, lyophilized ovarian weight was similar for both groups. Within the ULO group, removal of the ovary having the largest follicle(s) did not prevent an increase in ovarian weight or follicular fluid weight of the remaining ovary. Unilateral ovariectomy had no effect on the total number of follicles (1 to 6 mm) per ovary; however, the number of large (5 to 6 mm) follicles per ovary was increased (P<0.05) following ULO. By 12 hours after ULO there was a transient increase (P<0.05) in the circulating concentrations of FSH. Circulating concentrations of luteinizing hormone (LH) were either low or undetectable in these prepubertal ewes and no LH response was observed following ULO. These results indicate that compensatory ovarian hypertrophy in ULO prepubertal ewes is accompanied by a transient rise in circulating FSH concentrations.     

Gonadotropin releasing hormone treatment of dairy cows with ovarian cysts. I. Gross ovarian morphology and endocrinology

Dairy cows diagnosed as having ovarian cysts were assigned to receive either sterile water or 100 mug GnRH (5 cows/group). Immediately prior to treatment and three days post-treatment, ovaries were observed via paralumbar laparotomy, photographed and visible structures and ovarian size recorded. Nine to thirteen days post-treatment, ovaries were removed. Blood plasma was collected for hormone determinations prior to each surgery, 1.5 and 3.0 hours and 1, 5 and 9 days post-treatment. Although concentrations were similar between groups prior to treatment, concentrations of progesterone were higher and LH and estradiol-17beta lower for GnRH treated cows than control cows, immediately prior to ovariectomy. A layer of luteal tissue approximately 5 mm thick was present around the periphery of the cystic structure at ovariectomy in 4 of 5 GnRH treated cows, but in only one control cow. The thickness of the luteal layer around the periphery of the ovarian cysts was correlated -.82, .78 and -.63 with estradiol-17beta, progesterone and LH, respectively. In summary, response to GnRH treatment in cows with ovarian cysts appears to be characterized in most cases by luteinization of the cystic structures.     

Inequality in function of the right and left ovaries and uterine horns of the mouse

Inequality in function of the left and right ovaries and uterine horns of mice was evaluated in three separate experiments. In Exp. 1, the effect of position in the reproductive tract on various reproductive characteristics was evaluated in 158 pregnant hybrid mice. Ovulation rate, number of fetuses, total fetal weight and total placental weight were higher (P less than 0.05) on the right than the left on Day 18 of pregnancy (vaginal plug = Day 1). In Exp. 2, the effect of previous sham or unilateral ovariectomy (right or left) in mated Swiss-Webster mice was compared with unoperated mated controls (N = 17-24/treatment). In control mice, ovulation rate, total fetal weight and ovarian weight were higher (P less than 0.05) on the right than left side. Surgery (sham or unilateral, ovariectomy) decreased (P less than 0.005) ovulation rates, number of fetuses, ovarian weights, total fetal weight and total placental weight on Day 18 of pregnancy. Unilateral ovariectomy decreased (P less than 0.05) ovulation rates and ovarian weights more than did sham operation. Ovulation rates were higher (P less than 0.01) when the left ovary was manipulated or removed rather than the right ovary. For Exp. 3, pairs of 8 hybrid mouse embryos each (morulae and blastocysts) were surgically transferred to the left and right uterine horns of the same (bilateral, N = 15) or different (unilateral, N = 28) Swiss-Webster recipients. In almost all incidences, embryo survival (to Day 18 of pregnancy) was twice as high (P less than 0.05) in right than left uterine horns. We conclude that the left and right ovaries and uterine horns are not equal in function in Swiss-Webster and a hybrid strain of mice.     

Auto and heterotransplantation of the ovary to the uterus or parotid region in beef cows and prepuberal heifers

Eighteen mature estrous cycling beef cows and 9 prepuberal heifers were stratified by breed, age and weight to determine the effect of ovary-transplantation to a proximal site (right uterine horn) (U) and distal site (parotid region) (P) upon ovarian activity. Active ovaries (AO), ovaries with the corpus luteum (CL), were autotransplanted to the myometrium of the U in 3 cows and to the muscles of the P in 2 cows and their inactive ovaries (IO), ovaries without a CL, remained. Active ovaries of 6 cows were removed and heterotransplanted to 6 prepuberal heifers and their 10 were heterotransplanted to the U or the parotid (3). Six heifers received either a mature AO in the U or in the parotid. Three heifers were ovariectomized and their ovaries were heterotransplanted to 6 cows, 3 per site. Cows and heifers were slaughtered randomly 2 months after surgery and their ovaries were collected for microscopic and histological analysis. The transplants were successfully accomplished in 94% of the cows and in 83% of the heifers. Both of the unsuccessful heterotransplantations were located in the uterus. More estrous activity was found (P<.025) in cows than in heifers with their own ovaries in situ . All prepuberal ovaries in situ showed follicular development when mature AO were transplanted to either the U or parotid. The same trend was found in prepuberal ovaries transplanted to mature cycling cows. Cows with an IO in situ and AO transplanted to either site had more estrous activity than did ovariectomized cows with an IO transplanted to either site. Pregnancy rates in mature cycling cows with an least one ovary in situ were higher (P<.005) in cows with an ovary in the parotid region than cows with an ovary transplanted to the uterus.     

Effects of unilateral ovariectomization on the numbers of sperm in the oviducts, uterus and cervix of rabbits

The experiment was designed to determine the effect of removing one of the rabbits' ovaries on the numbers of sperm in the oviducts, uterine horns and cervices. The possible relationship between the anatomical asymmetry of the two sides of the reproductive tract and the distribution of sperm within different segments of the tract was also studied. Fifteen female rabbits were used; five were kept intact as the control group, five were right ovariectomized and five were left ovariectomized. All rabbits were injected with 50 IU HCG to induce ovulation and then inseminated with 60x10(6) sperm in 0.25 ml semen. Does were inseminated one month after unilateral ovariectomy. Animals were sacrificed 10 hrs later and sperm was recovered from the right and left oviducts, uterine horns and cervices. Unilateral ovariectomy significantly reduced the total numbers of sperm recovered as compared with intact does. The total numbers of sperm recovered from each of the two sides of the tract were not affected by the site of the removed ovary. Sperm numbers were high in the cervices of all groups and then decreased gradually in the upper segments of the tract. Sperm numbers that reached the oviduct of the intact rabbits were greater than those of both unilateral ovariectomized groups of rabbits. Differences between the length of the left and right cervices and uterine horns were not significant, but the right oviduct was significantly longer than the left oviduct.     

Demonstration of a critical period of ovarian activity in the control of early receptivity induced by estrogen in the female rat with 4-day cycles]

A significant decrease in early receptivity during the night from dioestrus II to prooestrus was observed in estrogen-treated 4-day cyclic rats following bilateral ovariectomy on dioestrus II at 4-5 p.m. Early receptivity appeared then to be dependent on the presence of ovary at this stage of the cycle. The mechanism whereby the adrenals may compensate for the ovaries when removed on dioestrus I, at 10-11 a. m. (Roos et al. 1973), was not observed in the present experimental conditions.     

Selective immunocytochemical localisation of calretinin in the human ovary

 Calretinin is a calcium-binding protein which is primarily expressed by certain cells of the nervous system, both central and peripheral. Its presence in non-excitable cells has been little studied. Using a polyclonal antibody and paraffin sections we have analysed the presence of calretinin in the human ovary of different ages, and in polycystic ovaries. Our results revealed the selective presence of calretinin, specifically localised in the cells of the germinal epithelium, those of the theca interna and the theca lutein cells, in the cells of the neuro-vaso-epithelial association and of the canalicular structures of the mesovarium. Calretinin was also present in a few cells of the theca externa and some interstitial cells. No appreciable quantitative differences in the strength of the positive reaction were seen between the ovaries of different ages or between the normal and the polycystic ovaries. The presence of calretinin was confirmed by western blot analysis. The selective presence of calretinin in the human ovary, in androgenic cells and in the cells of the germinal epithelium is discussed in relation to its possible function as a Ca²⁺ buffer. Accepted: 2 June 1997     

Immunohistochemical detection of estrogen receptor alpha in the growing and regressing ovaries of newly hatched chicks

The aim of this study was to detect the presence of estrogen receptor alpha in different cell subpopulations of the growing left and regressing right ovaries from newly hatched chicks, by immunohistochemical methods, using an indirect immunoperoxidase technique. Newly hatched chicks were killed by decapitation and the growing left and regressing right ovaries were removed and processed for histological and immunohistochemical studies. The percentage of estrogen receptor alpha (ER) immunostained cells and the staining intensity were determined. Histological results demonstrated that the right ovary lacks cortex and is constituted by the medullary region, whereas the left ovary is composed by cortical and medullary compartments. The medullary region is similar in both ovaries and presents the same elements. Immunohistochemical analysis revealed ER-positive cells in the left ovary, located in the nucleus of all cell subpopulations; in contrast, in the right ovary, only epithelial cells of the lacunar channels depicted estrogen receptors. The present findings indicate a cell-specific localization of ER in left and right ovaries of newly hatched chick.     

Initiation and termination of host-seeking inhibition in Aedes aegypti during oöcyte maturation

The inhibition of host-seeking behaviour that accompanies vitellogenesis in the mosquito, Aedes aegypti, was examined by the removal and implantation of ovaries. Mosquitoes ovariectomized before a blood meal and between 1 and 6 hr after a blood meal responded to a host at 48 hr after a blood meal. However, when ovariectomy was delayed until 10 hr after the meal or later, most mosquitoes did not respond to the host. When a partial ovary was present for only the first 12 hr after a meal, there was no host-seeking inhibition at 48 hr, and only 58% of females with one complete ovary present during this time interval responded. Howver, these same amounts of ovarian tissue inhibited host-seeking when they remained for 48 hr after a meal. Vitellogenic ovaries from donors blood-fed 8–24 hr before, implanted into sugar-fed recipients, did not affect the host-seeking behaviour of these recipients. Ovaries removed and reimplanted before the blood meal inhibited host-seeking at 72 hr after the blood meal only in the absence of oviposition from intact ovaries. It is concluded that 2 humoral factors are involved in the promotion of host-seeking inhibition: the first factor is produced by the ovaries, and after reaching a critical threshold in the haemolymph, stimulates the release of a second factor that acts directly to inhibit mosquito behaviour. An ovary which retains 2 or fewer eggs after oviposition terminates the inhibition via nervous pathways. The role of 20-hydroxyecdysone in the behavioural inhibition is discussed.     

Ovarian contraction in various teleost families

Fishes from 12 species (a minimum of three fish of each species), representing nine families were examined for ovarian contraction. An ovary from each fish was removed, placed in a muscle bath and assessed for contractions using a force-displacement transducer. After at least 30 min of observation for spontaneous contractions, acetylcholine (ACh) was added to the muscle bath to assess the ovary's capacity for contraction. At least one third of the ovaries from each species contracted spontaneously or in response to 10⁻⁵ M ACh. Mean ± s . e . frequencies of spontaneous contractions ranged from 7·5 ± 2·0 h⁻¹ in the Atlantic silverside Menidia menidia to 380·3 ± 101·5 h⁻¹ in the sheepshead minnow Cyprinodon variegatus . Simultaneously tested ovaries from a single white perch Morone americana contracted at rates of 31·4 and 81·9 h⁻¹. This is consistent with independent generation of the contractile rhythm in the two ovaries. In three species (goldfish Carassius auratus , mummichog Fundulus heteroclitus and white perch), the tunica albuginea was removed from the ovary and found to be capable of independent contraction. This suggests that this membrane contributes to the observed contractions. The presence of ovarian contractions in this varied group of fish species indicates that the contractions play an important role in reproduction.     

Effects of unilateral ovariectomy on follicular development and ovulation in cattle

In a study of 4 cyclic dry cows (Trial I) and 6 cyclic puberal heifers (Trial II), unilateral ovariectomy increased the number of ovulatory follicles, did not alter the hormone profile, cycle length or the number of follicular waves. Ovarian follicular development in all 4 cows was monitored daily using transrectal ultrasonography until the day of ovulation, during which period daily blood samples were also taken from the tail vein for determination of plasma FSH, LH and P4 concentrations. Unilateral ovariectomy was performed on the day after ovulation and ovarian activity was again monitored daily (ultrasonography and blood sampling for FSH, LH and P4) for 2 consecutive cycles (8 cycles in all). Estrus in all 6 heifers was synchronized using 2 injections of PGF2 alpha given 12 d apart. Similarly, ovarian activity in the 6 puberal heifers was monitored daily using ultrasonography and blood sampling for 1 complete control cycle. Following estrus and ovulation the left ovary was removed in all the animals, and thereafter 1 complete cycle was followed. Mean cycle length, FSH, LH and P4 concentrations before and after unilateral ovariectomy were compared using paired sample t-test. The results show that unilateral ovariectomy neither altered the cycle length nor the number of follicular waves in the cows, but it increased the number of ovulatory follicles (2 follicles developed and ovulated in 6 of the 8 cycles). The mean diameter of the largest follicle was 16.1 +/- 0.9 mm and the second largest 12.5 +/- 0.9 mm. No significant (P > 0.05) differences were observed in FSH (0.72 +/- 0.09 vs 0.71 +/- 0.07), LH (0.42 +/- 0.1 vs 0.37 +/- 0.07) and P4 (2.8 +/- 0.6 vs 2.6 +/- 0.4) levels before and after unilateral ovariectomy. Of the 6 heifers, 5 had 2 waves and 1 heifer had 3 waves of follicular growth during the control cycle, and this pattern did not change after the procedure. Mean cycle length (20.7 +/- 0.9 vs 21 +/- 0.9) did not differ before and after unilateral ovariectomy, and 4 of the 6 heifers ovulated twin follicles following ovariectomy. The mean diameter of the largest follicle was 14.5 +/- 0.7 mm and second largest measured 12.1 +/- 0.8 mm. No significant (P > 0.05) differences were observed in FSH (0.16 +/- 0.09 vs 0.21 +/- 0.07), LH (0.11 +/- 0.1 vs 0.15 +/- 0.07) and P4 levels (3.6 +/- 0.26 vs 3.8 +/- 0.29) before and after unilateral ovariectomy. Based on these results, we conclude that unilateral ovariectomy is an ideal method for obtaining twin ovulations in cows and heifers.     

Relationship between concentrations of immunoreactive insulin-like growth factor-I in follicular fluid and various biochemical markers of differentiation in bovine antral follicles

Three experiments were conducted to determine the relationship between concentrations of insulin-like growth factor-I (IGF-I) in ovarian follicular fluid and various biochemical markers of follicular differentiation in bovine follicles. In Experiment I, ovaries were removed on Days 7, 14, 28, 42, or 56 after parturition from a total of 21 cows. In Experiment II, ovaries of 31 cows were removed between Days 20 and 30 postpartum after 48 or 96 h of either saline (0.9% NaCl, 5 ml) or luteinizing hormone-releasing hormone (LHRH, 500 ng/5 ml saline) injections given every 2 h via jugular cannulae. In Experiment III, ovaries of six cows were removed 48-50 h after a 35-mg injection of prostaglandin F2 alpha during the midluteal phase of an estrous cycle. In Experiments I and II, all follicles greater than or equal to 8.0 mm in diameter were removed from each ovary (n = 33 and 46, respectively). In Experiment III, fluid from all follicles greater than 4 mm in diameter were removed individually (n = 10), and fluid from follicles 1-4 mm in diameter were pooled for each cow. Follicles for each experiment were further categorized as either estrogen-active (E-A, concentration of estradiol greater than progesterone in follicular fluid) or estrogen-inactive (E-I, concentration of progesterone greater than estradiol in follicular fluid). Measurements of immunoreactive IGF-I (i-IGF-I) were made after separating IGFs from their binding proteins with an acid-ethanol extraction.(ABSTRACT TRUNCATED AT 250 WORDS)     

Histological investigation on the ovarian cycle of the bluefin tuna in the western and central Mediterranean

The histological analysis of eastern Atlantic bluefin tuna Thunnus thynnus ovaries caught from February to September 1999–2000, made it possible to distinguish the presence of seven oocyte developmental stages and allowed the characterization of six time-dependent ovary maturity stages. The ovaries of mature (fork length, L _F ≥ 110 cm) bluefin tuna were non-active from August (spent period) to March (quiescent period) when they contained only perinucleolar-stage oocytes. Ovary development started in April to early May (recrudescent period) with the appearance of oocytes at the lipid stage. Vitellogenesis appeared in mid-May (ripening period) and post-vitellogenesis occurred in late May to mid-June (pre-spawning period). In late June to early July, hydrated oocytes, a sign of imminent spawning, were found only in specimens caught in Balearic waters. Females ranging between 100 and 110 cm L _F, captured during the recrudescent and ripening periods, had the largest oocytes at the lipid stage, most of which were degenerating. An extensive vitellogenic atresia was observed in the ovaries of five females caught during the spawning period in non-spawning areas.     

The inter-ovarian distribution of dominant follicles is influenced by the location of the corpus luteum of pregnancy.

The objective was to characterise the distribution of dominant ovarian follicles in the early post-partum period in relation to the side of the preceding pregnancy and its relationship with the left and right ovaries. Primiparous cows were enrolled over a 2-year period (n = 33 in Year 1 and n = 28 in Year 2). Ovarian follicles were observed daily by trans-rectal ultrasonography commencing within 9 days of calving. Dominant follicles (DF) were described as occurring on the ovary ipsilateral to the CL of preceding pregnancy (ipsilateral ovary of pregnancy, IOP) or contralateral to the CL of the preceding pregnancy (contralateral ovary of pregnancy, COP), and as occurring on the left or right ovary. Results in Year 1 were analysed for the effect of breed (Friesian n = 15; Jersey n = 18). There was a bias towards the COP for the first DF post-partum in both breeds (DF1; 70%; p<0.05). A breed interaction was observed with the second DF post-partum with a bias towards the COP in the Friesian (93%; p<0.05); but not the Jersey animals (50%). In Year 2, all cows were Friesians, and there was again a biased distribution of the DF1 towards the COP (89%; p<0.05) and for the combined distribution of the first three DF post-partum (76%; p<0.05) as well as the first ovulatory follicle (71%; p<0.05). A comparison of the pooled data for the location of the DF1 from both years showed that only one DF1 was observed on a left ovary in the 29 cases where the preceding pregnancy was also on the left side. This study demonstrated a bias in the distribution of DL in the early post-partum period towards the ovary on the side opposite that of the preceding pregnancy as well as towards the right side.     

Detection of VHSV IVb within the gonads of Great Lakes fish using in situ hybridization

Viral haemorrhagic septicaemia virus (VHSV) genotype IVb was recently detected as the cause of numerous mortality events in Great Lakes fish. In situ hybridization was used to examine the gonads from 13 fish, including freshwater drum Aplodinotus grunniens and muskellunge Esox masquinongy that were infected naturally, as well as rainbow trout Oncorhynchus mykiss and fathead minnows Pimphales promelas, which were experimentally infected. Although the ovaries and testes of fish infected by VHSV IVb had few lesions, viral RNA was present in the ovaries of the rainbow trout and fathead minnow and was abundant in the gonads of muskellunge and in the ovaries of freshwater drum. Viral RNA was present mainly surrounding yolk vacuoles/granules or adjacent to the germinal vesicle, with lesser amounts found within the germinal vesicle, in the mesovarium and/or tunica albuginea and blood vessels of the ovary. Viral RNA was also found in and surrounding primary and secondary spermatocytes of the muskellunge.     

Unilateral ovariectomy restores ovulatory cyclicity in rats with a polycystic ovarian condition

An acyclic polycystic ovarian condition can be induced in adult rats with a single injection of estradiol valerate (EV). The ovaries are small and contain multiple cystic follicles and no new corpora lutea. In the early stages of the condition, both basal plasma luteinizing hormone (LH) and LH responses to luteinizing hormone-releasing hormone (LHRH) are attenuated. Plasma androgens are indistinguishable from normal controls. The present study examines the effect of unilateral ovariectomy (ULO) on this condition. Removal of one cystic ovary results in almost immediate resumption of vaginal cyclicity that persists for at least 3 wk. At 1 or 3 wk after ULO the remaining ovary contains fresh corpora lutea, appears histologically normal, and is significantly heavier than the cystic ovary removed at ULO, indicative of compensatory hypertrophy. Despite the resumption of apparently normal cyclic function, basal plasma LH concentrations and LH responses to LHRH are not significantly better than those in intact animals with polycystic ovaries. Thus, the previously polycystic ovary is fully capable of normal ovulatory function despite obvious impairments in the hypothalamo-pituitary axis. Since ovulatory function resumes on a background of continued poor pituitary responsiveness, the primary defect, which ULO corrects, is probably at the hypothalamic level. Finally, the cystic ovary clearly contributes to the hypothalamic aberration to which it subsequently responds.     

Ipsilateral vagotomy to unilaterally ovariectomized pre-pubertal rats modifies compensatory ovarian responses

The present study evaluates the participation of the vagus nerve in pre-pubertal rats with unilateral ovariectomy on puberty onset, and on progesterone, testosterone and estradiol serum levels, and the compensatory responses of the ovary. Unilateral vagotomy did not modify the onset of puberty in unilaterally ovariectomized rats. Ovulation rates of animals with the left vagus nerve sectioned and the left ovary in-situ was lower than in rats with only unilateral ovariectomy. Sectioning the left vagus to 32-day old rats with the left ovary in-situ resulted in lower compensatory ovarian hypertrophy than in rats with right unilateral ovariectomy. Twenty-eight or 32-day old animals with sectioning of the right vagus nerve and the right ovary in situ showed higher compensatory ovulation. Twenty-eight -day old rats with the right ovary in situ had higher progesterone and testosterone levels than animals of the same age with the left ovary in-situ. Compared to animals with the right ovary in situ, animals treated at 32-days of age, sectioning the ipsi-lateral vagus nerve resulted in higher progesterone levels. Higher progesterone levels were observed in 28- and 32 days old rats with the left ovary in situ and left vagus nerve sectioned. Thirty-two day old animals with the right ovary in situ and right vagus nerve sectioned had higher progesterone levels than rats of the same age with the left ovary in situ and left vagus nerve sectioned. Left vagotomy to 28-day old rats with the left ovary in situ resulted in higher testosterone levels, a reverse response to that observed in animals with sectioning of the right vagus and the right ovary in situ. Thirty-two day old rats with the left ovary in situ and left vagus nerve sectioned showed lower testosterone levels than animals without vagotomy and with the left ovary in situ.