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PubMed1997

Comparison of long-term effects of ovariectomy versus ovariohysterectomy in bitches.

Although ovariectomy is less invasive and less time-consuming than ovariohysterectomy, most surgical textbooks recommend ovariohysterectomy for routine neutering of bitches. This advice is probably based on concerns about the development of uterine disease after ovariectomy. However, there is no evidence that conditions such as cystic endometrial hyperplasia (CEH)-endometritis develop in the ovariectomized bitch, unless progestagens are administered. The purpose of this study was therefore to compare the long-term effects of ovariectomy and ovariohysterectomy, including the incidence of urinary incontinence. Questionnaires were sent to 264 owners of bitches, in which ovariectomy (126) or ovariohysterectomy (138) had been performed as a routine neutering procedure 8-11 years earlier. Complete data were available for 69 bitches of the ovariectomy group and for 66 bitches from the ovariohysterectomy group. There were no indications that endometritis had developed in bitches of the ovariectomy group. None of the bitches was sexually attractive to male dogs after neutering. The occurrence of a clear to white vaginal discharge was reported in two bitches of each group, but none of these four bitches appeared to be ill during the periods when the discharge was present. Furthermore, with the exception of urinary incontinence, no problems were reported that could be related to the surgical neutering. Six of the ovariectomized bitches and nine of the ovariohysterectomized bitches eventually developed urinary incontinence. Of these 15 bitches (11%), 12 weighed more than 20 kg. Bouvier des Flandres bitches were at a higher risk of developing urinary incontinence than were those of the other breeds. The possibility that the urinary incontinence was due at least in part to other conditions must be considered, since eight of the bitches were 9 years or older before urinary incontinence occurred and seven of the incontinent bitches also had polyuria or polydipsia. There were no significant differences in the incidence of urogenital problems listed above between the bitches of the ovariectomy and ovariohysterectomy group. It is hypothesized that a uterine disease such as CEH-endometritis cannot develop after complete ovariectomy, unless progestagens are administered. The results of this study indicate that ovariectomy does not increase the risk of CEH-endometritis or other complications in comparison with ovariohysterectomy. It is concluded that there is no indication for removing the uterus during routine neutering in healthy bitches. On the contrary, ovariectomy should be considered the procedure of choice.

Animals↗

PubMed1990

Variable effect of unilateral or bilateral ovariectomy performed in young or adult animals on tissue plasminogen activator activity, plasminogen activator inhibition and plasmin inhibition.

Unilateral or bilateral ovariectomy was performed in young and adult rats. Mainly bilateral ovariectomy induced variable changes of plasminogen activator activity (PAA), plasminogen activator inhibition (PAI) and plasmin inhibition (PI) in key organs (brain, lungs, heart, aorta and kidneys). The most remarkable changes were induced after bilateral ovariectomy performed in young animals and mostly after two and three months of ovariectomy. Therefore, the effect of ovariectomy on tissue PAA, PAI or PI was variable and dependent on the extent of the ovariectomy (unilateral or bilateral), the age of the animal at ovariectomy (young or adult), the time after ovariectomy, and the organ. An additional interesting finding was the dissociation in the response of tissue anti-t-PA and anti-u-PA activities to ovariectomy in some of the organs studied.

Animals↗

PubMed1998

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.

Animals↗

PubMed2004

Ovariectomy is sufficient to accelerate spontaneous skin ageing and to stimulate ultraviolet irradiation-induced photoageing of murine skin.

BACKGROUND: Wrinkling and sagging of the skin during photoageing is physiologically associated with diminished elasticity, which can be attributed to increased fibroblast-derived elastase activity. This degrades the dermal elastic fibres needed to maintain the three-dimensional structure of the skin. We previously reported that ovariectomy accelerates ultraviolet (UV)B-induced wrinkle formation in rat hind limb skin by altering the three-dimensional structure of elastic fibres. OBJECTIVES: In this study, we used hairless mice to assess the effects of ovariectomy with or without chronic UVA or UVB radiation on sagging and wrinkling of skin, on the elasticity of skin, as well as on matrix metalloproteinase activities in the skin. METHODS: Ovariectomies or sham operations were performed on 6-week-old female ICR/HR hairless mice. RESULTS: Even in the ovariectomy group without UV irradiation, the skin elasticity was significantly decreased during the 3-13 weeks after ovariectomy, which was accompanied by a significant increase in elastase activity in the skin. After UVA or UVB irradiation, skin elasticity was significantly decreased to a greater extent in the ovariectomy group than in the sham operation group, and this was accompanied by a reciprocal increase in elastase activity but not in the activities of collagenases I or IV in the skin. Consistent with the decreased skin elasticity, UVA irradiation for 12 weeks elicited more marked sagging in the ovariectomy group than in the sham operation group. UVB irradiation for 12 weeks also induced more marked wrinkle formation in the ovariectomy group than in the sham operation group. CONCLUSIONS: These results suggest that ovariectomy alone is sufficient to accelerate skin ageing and to increase UV sensitivity, which results in the further deterioration of the skin and photoageing, and may account for the accelerated skin ageing seen in postmenopausal women.

Animals↗

PubMedDate not supplied

Effect of ovariectomy on histological change and protein expression in female mouse reproductive tracts.

Proliferation of the vagina and uterus in rodents is stimulated by ovarian estrogen, and ovariectomy induces regression of these tracts. In mouse, reproductive tracts, organ weights, vaginal epithelial thickness, the number of epithelial cell layers, and uterine epithelial cell height were significantly reduced 1 to 20 days after ovariectomy when compared with those of intact, mice taken at the estrous stage. No significant differences in those parameters were found between ovariectomized mice implanted with estradiol and intact estrous mice. Vaginal epithelium at estrus was composed of 10-15 layers of epithelial cells with superficial keratinized layers, however, the vaginal epithelium began to regress one day after ovariectomy. Infiltration of leukocytes was encountered in the vaginal epithelium 2-3 days after ovariectomy. Protein expression in the regressing vagina and uterus after ovariectomy was examined by two-dimensional polyacrylamide gel electrophoresis. After ovariectomy, new proteins appeared in the regressing vagina, but not in the regressing uterus. Expressions of 7 and 6 proteins in the vagina and uterus, respectively, reached peak levels 2-3 days after ovariectomy. The expression of ovariectomy-specific proteins and infiltration of leukocytes in vaginal epithelium was inhibited by the injection of cycloheximide, an inhibitor of protein synthesis. These results suggest that some proteins participate in the regression of mouse reproductive tracts after estrogen withdrawal induced by ovariectomy.

Animals↗

PubMed1998

Ovariectomy and estrogen-induced alterations in myocardial contractility in female rabbits: role of the L-type calcium channel.

The effects of ovariectomy and estrogen replacement on myocardial contractility were examined in female rabbits. Ovariectomy failed to alter left ventricular mass, papillary muscle cross-sectional area or isometric force. Estrogen replacement after ovariectomy (0.15 microg/kg/day i.m. 17beta-estradiol acetate for 7 days) increased left ventricular mass and papillary muscle mass, and reduced isometric force compared to control and ovariectomy groups. Ovariectomy did not alter increased isometric force with isoproterenol, but decreased the ED50 for Bay K8644 (compared to control and estrogen groups). Estrogen replacement increased the ED50 for isoproterenol- and Bay K8644-induced isometric force compared to control and ovariectomy groups. Ovariectomy increased and estrogen replacement decreased isometric force associated with increased Ca++o. Acute exposure to 17beta-estradiol or diethylstilbesterol (10(-7) M, 10(-6) M) failed to alter isometric force in control papillary muscles. Estrogen replacement reduced the number, but not the dissociation constant for 3H-nitrendipine binding in plasma membrane preparations (compared to ovariectomy and control groups). Peak L-type calcium currents in isolated ventricular myocytes from the three treatment groups were not significantly different. The data are consistent with an ovariectomy-induced increase and estrogen-induced decrease in L-type calcium channel density in rabbit myocardium. Estrogen-induced alterations in L-type calcium channel expression and contractility are subsequently modified by estrogen-induced cardiac hypertrophy.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗

PubMed1990

Effect of ovariectomy and prednisolone on bone mineral content in rats: evaluation by single photon absorptiometry and radiogrammetry.

The effects of ovariectomy and prednisolone were studied for 9 months in 3-month-old rats on a moderately low calcium diet. Measurements were made by single photon absorptiometry of the femur at cortical and trabecular bone sites. Radiogrammetry was performed at the midshaft of the femur. During growth, body weight, bone size, and bone mineral content (BMC) increased in male rats more than in females. After ovariectomy, body weight increase was more pronounced, but bone mineral increase was lower than in controls. At the distal end of the femur, bone mineral density decreased after 3 months, and at the midshaft of the femur, medullary width increased significantly from 6 months on. Prednisolone in a dose of 0.5 mg/kg/day did not influence BMC. However, prednisolone treatment after ovariectomy induced a more pronounced effect on bone than ovariectomy alone. BMC increase was lower than in ovariectomy, and bone mineral density decreased significantly, especially at the distal end of the femur. After correction for differences in body weight, globally the same results were found. We conclude that (1) the combination of single photon absorptiometry and radiogrammetry allows the evaluation of growth and the effect of ovariectomy and prednisolone treatment in rats; (2) ovariectomy results in bone loss first at the distal end and later in the midshaft of the femur; (3) prednisolone in a dose of 0.5 mg/kg/day alone did not affect bone mass; and (4) prednisolone profoundly enhanced the effects of ovariectomy.

Absorptiometry, Photon↗

PubMed1995

Ovariectomy decreases plasma triglyceride levels in analbuminaemic rats by lowering hepatic triglyceride secretion.

In mutant analbuminaemic rats (NAR), females demonstrate a more marked hypertriglyceridaemia than males. Ovariectomy decreases triglyceride levels in female NAR. We measured triglyceride secretion rates in vivo as well as the activity of acetyl CoA carboxylase (ACC) and fatty acid synthase (FAS) in hepatic cytosol obtained from female control Sprague-Dawley (SD) rats and NAR with or without ovariectomy. NAR were severely hyperlipidaemic, and triglyceride, cholesterol, apolipoprotein A-I and plasma protein concentrations levels were decreased (all P < 0.01) by ovariectomy. Only triglyceride levels were decreased by ovariectomy in the SD rats (P < 0.05). Oestradiol treatment in ovariectomized NAR restored plasma protein and triglyceride concentrations to levels similar to those observed in intact female NAR and caused a marked increase in plasma cholesterol. Ovariectomy in NAR reduced lipoprotein triglycerides and cholesterol in VLDL, IDL and LDL1, but had little effect on the triglyceride-cholesterol ratio of these particles. Both ACC and FAS activities were markedly increased in NAR vs. SD rats (P < 0.01). This increase was partially corrected by ovariectomy. There was no significant effect of ovariectomy on ACC or FAS activity in the SD rats. Triglyceride secretion rates were significantly increased in NAR vs. SD rats (135 +/- 10 vs. 103 +/- 12 nmol/min per 100 g body weight; P < 0.05). Ovariectomy markedly decreased triglyceride secretion rate in NAR to 69 +/- 6 (P < 0.01), but not in SD rats (92 +/- 8 nmol/min per 100 g body weight, NS). Oestradiol treatment in ovariectomized SD rats restored triglyceride levels but had no significant effect on triglyceride secretion rate (106 +/- 23 nmol/min per 100 g).(ABSTRACT TRUNCATED AT 250 WORDS)

Acetyl-CoA Carboxylase↗

PubMed2004

Tob deficiency superenhances osteoblastic activity after ovariectomy to block estrogen deficiency-induced osteoporosis.

Tob (transducer of erbB2) is a member of antiproliferative family proteins and acts as a bone morphogenic protein inhibitor as well as a suppressor of proliferation in T cells, which have been implicated in postmenopausal bone loss. To determine the effect of Tob deficiency on estrogen deficiency-induced bone loss, we analyzed bone metabolism after ovariectomy or sham operation in Tob-deficient mice. Ovariectomy in WT mice decreased trabecular bone volume and bone mineral density (BMD) as expected. In Tob-deficient mice, ovariectomy reduced bone volume and BMD. However, even after ovariectomy, both trabecular bone volume and BMD levels in Tob-deficient bone were comparable to those in sham-operated WT bones. Bone formation parameters (mineral apposition rate and bone formation rate) in the ovariectomized Tob-deficient mice were significantly higher than those in the ovariectomized WT mice. In contrast, the ovariectomy-induced increase in the bone resorption parameters, osteoclast surface, and osteoclast number was similar between Tob-deficient mice and WT mice. Furthermore, in ex vivo nodule formation assay, ovariectomy-induced enhancement of nodule formation was significantly higher in the bone marrow cells from Tob-deficient mice than in the bone marrow cells from ovariectomized WT mice. Both Tob and estrogen signalings converge at bone morphogenic protein activation of alkaline phosphatase and GCCG-reporter gene expression in osteoblasts, revealing interaction between the two signals. These data indicate that Tob deficiency prevents ovariectomy-induced bone loss through the superenhancement of osteoblastic activities in bone and that this results in further augmentation in the bone formation rate and the mineral apposition rate after ovariectomy in vivo.

3T3 Cells↗

PubMed1996

Effect of ovariectomy on the in vitro and in vivo activation of carcinogenic N-2-fluorenylhydroxamic acids by rat mammary gland and liver.

N-Hydroxy-N-2-fluorenylacetamide (N-OH-2-FAA) and its benzamide analogue N-OH-2-FBA are mammary gland carcinogens in the female Sprague-Dawley rat. Ovariectomy inhibits tumorigenicity of topically applied N-OH-2-FAA suggesting modulation of carcinogen-activating enzymes in the gland. This study concerned the activation of N-OH-2-FAA and N-OH-2-FBA by the mammary gland and liver, a chief site of metabolism, from 50-day-old female rats and effects on the activation of ovariectomy performed at 22 days of age. The levels of N-debenzolyation of N-OH-2-FBA to N-hydroxy-N-2-fluorenamine (N-OH-2-FA), catalyzed by microsomal carboxylesterases in mammary gland and liver were similar and increased 1.5- and 1.7-fold, respectively, by ovariectomy. N-Debenzoylating activity in cytosols of both tissues appeared to be partially of microsomal origin. Mammary gland cytosol contained N-, O- and N,O-acyltransferase activities at levels 40-50% those of liver. N-Acyltransferase activity was determined via acetyl coenzyme A (AcCoA)-dependent acetylation of 2-FA and a new assay, N-OH-2-FAA-dependent acetylation of 9-oxo-2-FA. The latter activity was decreased in mammary gland by ovariectomy. Microsomal N-acyltransferase activities were <36% those of cytosols. AcCoA-dependent binding of N-OH-2-[ring-[3H]FBA to DNA, catalyzed by cytosol, was consistent with a two-step activation of N-OH-2-FBA involving esterase-catalyzed N-debenzoylation to N-OH-2-FA and its O-acyltransferase-catalyzed acetylation to the electrophilic N-acetoxy-2-FA. O-Acetyltransfer by mammary gland appeared to be rate-limiting since ovariectomy-dependent increases in N-debenzoylation did not increase binding with S9 fraction. Little or no sulfotransferase-catalyzed binding of N-OH-2-[ring-3H]FBA-derived N-OH-2-[ring-3H]FA was detected in the liver or mammary gland cytosol, respectively. The level of binding of N-OH-2-[ring-3H]FAA to DNA catalyzed by cytosolic N,O-acyltransferase was decreased approximately 23% in mammary gland and increased 1.2-fold in liver by ovariectomy. 32P-Postlabeling analyses indicated a single adduct N-(deoxyguanosin-8-yl)-2-fluorenamine in DNA of both tissues 24 h after one intraperitoneal injection of N-OH-2-FBA or N-OH-2-FAA. Respective levels were 3.6- and 5.5-fold greater in liver than mammary gland. After ovariectomy, the adduct levels from N-OH-2-FBA increased 1.8-fold in mammary gland and from N-OH-2-FAA decreased approximately 50% in both tissues. Thus, the ovariectomy-dependent changes in levels of enzymes activating N-OH-2-FBA and N-OH-2-FAA were consistent with in vivo DNA adduct levels in the target mammary gland, but not in the liver.

Acetylation↗

PubMed1994

Interaction between dietary intake and ovariectomy on concentrations of insulin-like growth factor-I, GH and LH in plasma of heifers.

The objective of this study was to determine if alterations in dietary intake and(or) ovariectomy influence plasma concentrations of IGF-I, GH and LH in heifers. Cyclic heifers (n = 23) were individually fed for 10 wk either 1) 1.8% of body weight in dry matter per day (GAIN; n = 7) 2) 1.1% of body weight in dry matter per day (MAINT; n = 8); or 3) 0.7% of body weight in dry matter per day (LOSE; n = 8). After 10 wk of dietary treatment, heifers were ovariectomized 36 to 40 h following the second injection of prostaglandin F2alpha analog (2 injections 11 d apart). Heifers weighed 444 +/- 13, 387 +/- 8, and 349 +/- 9 kg in the GAIN, MAINT and LOSE groups, respectively, at the time of ovariectomy; the average daily weight gains during the 10-wk period were 0.96, 0.17 and -0.31 kg, respectively (P < 0.001), for the 3 groups. Blood plasma was collected for 6 h at 15-min intervals 1 d before and 2 wk after ovariectomy. The MAINT group of heifers had greater IGF-I concentrations than either the LOSE or GAIN groups; IGF-I decreased (P < 0.05) by 23 and 35% after ovariectomy in the MAINT and GAIN groups, respectively, but did not change (P > 0.10) in the LOSE groups. Dietary restriction tended to increase (P < 0.10) GH pulse frequency and mean GH. Ovariectomy had no effect (P > 0.10) on mean GH or GH pulse frequency but increased (P < 0.05) GH pulse amplitude in the GAIN groups. Dietary treatment had no effect (P > 0.10) on mean LH, or LH pulse amplitude and frequency. However, across dietary treatments, ovariectomy increased mean LH and LH pulse frequency but did not affect (P > 0.10) LH pulse amplitude. In summary, dietary restriction increased GH secretion while ovariectomy increased LH secretion. There appears to be a dichotomy of response between GH and IGF-I in the way heifers respond to dietary treatment and(or) ovariectomy.

Journal Article↗

PubMed1985

Changes in pulsatile LH secretion after ovariectomy in Ile-de-France ewes in two seasons.

Two experiments were conducted in Ile-de-France ewes to study changes in pulsatile LH secretion in ewes ovariectomized during anoestrus or during the midluteal phase of the oestrous cycle. In Exp. 1, blood samples were taken every 20 min for 12 h the day before ovariectomy (Day 0). After ovariectomy, samples were taken every 10 min for 6 h (10 ewes per group), on Days 1, 3, 7 and 15. In Exp. 2 samples were taken every 10 min for 6 h (10 ewes per group) on Days 7, 15, 30, 60, 90, 120, 150 and 180 after ovariectomy. Further samples were taken (5 ewes per group) at 9 and 12 months after ovariectomy. There were significant interactions between season and day of sampling for the interval between LH pulses in both experiments. LH pulse frequency increased within 1 day of ovariectomy and the increase was more rapid during the breeding season. There were clear seasonal differences in pulse frequency in Exp. 2. Compared with ewes ovariectomized in anoestrus, pulse frequency was significantly higher for ewes ovariectomized in the breeding season, from Day 7 until Day 120. Once pulse frequency had increased in ewes about the time of the normal breeding season, pulse frequency remained high and subsequent seasonal changes were greatly reduced. Pulse amplitude increased immediately after ovariectomy to reach a maximum on Day 7 and there were no differences between season of ovariectomy in the initial changes in amplitude. In Exp. 2, changes in amplitude followed changes in pulse interval and there was a significant interaction between season and day of sampling. There were no significant effects of season on nadir LH concentrations which increased throughout the duration of the experiments. These results show that, in ovariectomized ewes, LH pulse frequency observed on a given day depends on time after ovariectomy, season at the time of sampling and on previous exposure of ewes to stimulatory effects of season. The direct effects of season on LH pulse frequency and seasonal changes in sensitivity to steroid feedback may contribute to control of the breeding season and their relative contributions to the beginning and end of the breeding season may differ.

Animals↗

PubMed1989

Long-term ovariectomy and hormone-induced sexual behavior, progestin receptors, and hypothalamic morphology in female rats.

Long-term ovariectomy reduces the ability of estradiol and progesterone treatment to induce sexual receptivity in female rats. Previous researchers suggested that this effect may be due to a decreased induction of neural progestin receptors by estradiol in the long-term ovariectomized rats. The present study was designed to replicate and extend this finding, and to search for neuroanatomical correlates by measuring the volume of the ventromedial nucleus (VMN) of the hypothalamus, a putative site of action of estradiol and progesterone for the induction of female sexual behavior. Long-term ovariectomy (5 to 6 weeks) as compared to short-term ovariectomy (1 week) reduced the ability of estradiol-17 beta and progesterone treatment to induce sexually receptive and proceptive behaviors. Consistent with previous reports, our data show that the reduced levels of cytosol progestin receptors after long-term ovariectomy and estradiol treatment are related to a reduced ability of estradiol to induce the receptors. Long-term ovariectomy did not affect the concentration of cytosol progestin receptors in the preoptic area, suggesting a neuroanatomical specificity to this effect. Contrary to our predictions, long-term ovariectomy did not affect the volume of the VMN. In fact, estradiol treatment, while blocking the effect of long-term ovariectomy on sexual behavior, decreased the volume of the VMN. Therefore, the measurement of the volume of the VMN is not a good predictor of the responsiveness to steroid hormone induction of sexual behavior.

Animals↗

PubMed1994

The effects of ovariectomy and progesterone on peripheral aromatization in the female rhesus monkey.

We investigated the acute effects of surgery, i.e. ovariectomy, the long-term effects of ovariectomy, and the effects of progesterone on the peripheral aromatization of androstenedione in rhesus monkeys (Macaca mulatta). For the acute effects of surgery, 7 rhesus monkeys were given a pulse of [3H]androstenedione/[14C]estrone 2 weeks before and immediately after ovariectomy. In each case all urine was collected for 4 days and analyzed for radioactivity as estrone glucuronide and the peripheral aromatization calculated from the isotope ratios. Similarly, 5 monkeys were studied before and 18 months after ovariectomy. The acute effects of surgery resulted in a significant decrease in the peripheral aromatization of androstenedione to estrone from a mean +/- SE of 0.94 +/- 0.26 to 0.61 +/- 0.19%, P = 0.0452. Conversely, the long-term effects of ovariectomy resulted in a significant increase in peripheral aromatization from 0.38 +/- 0.06 to 0.67 +/- 0.12%, P = 0.0207. In 7 monkeys the peripheral aromatization was measured before and 10 days after the administration of progesterone, 100 mg in oil. There was no difference in peripheral aromatization before, 0.62 +/- 0.04% and after progesterone, 0.58 +/- 0.05%, P = 0.10. We conclude that the acute stress of ovariectomy, or possibly the loss of ovarian aromatizing tissue, results in a decline in peripheral aromatization, but ovariectomy will have the long-term effect of an increase in aromatization, and that the presence or absence of progesterone does not play a role.

Androstenedione↗

PubMed1991

Effect of early ovariectomy and steroid hormone replacement of embryo transport, development and implantation in mice.

Bilateral ovariectomy on Day 1 of pregnancy increased abnormal embryo numbers on Day 4 and delayed passage of embryos to the uterus. Progestins given on Day 1 reversed these effects; given on Day 3 they reduced numbers of abnormal embryos, but did not restore normal transport. Oestrogen given alone after ovariectomy increased embryo loss, but restored preimplantation embryo development to normal when given on Day 3 after progestins on Day 1. The results suggested that both oestrogen and progesterone were necessary for normal preimplantation embryo development in vivo. However, although Day-1 progestins produced the greatest improvement in embryo transport and preimplantation development, they supported only low implantation rates compared with progestins starting on Day 3, and no progestin treatment returned implantation rates to normal. Sham ovariectomy on Day 1 also reduced implantation rate, suggesting that surgical stress of Day-1 ovariectomy had major adverse effects on embryo viability. This view was supported by experiments involving unilateral ovariectomy, which produced abnormalities in embryo transport, development and implantation, but only on the operated side. Furthermore, the major abnormality induced in embryo development by unilateral and bilateral ovariectomy, viz embryonic autolysis, was not increased in experiments in which pregnancy was blocked by non-surgical antagonism of progesterone. It is concluded that abnormalities in embryo development induced by early ovariectomy are not caused by a deficit of endogenous hormones, but result largely from effects of surgical trauma on oviduct function which can be reversed by treatment with exogenous hormones.

Animals↗

PubMed1998

Multicenter randomized clinical trial of goserelin versus surgical ovariectomy in premenopausal patients with receptor-positive metastatic breast cancer: an intergroup study.

PURPOSE: To compare failure-free survival (FFS) and overall survival (OS) for patients with metastatic breast cancer treated with the gonadotropin-releasing hormone (GN-RH) agonist, goserelin versus surgical ovariectomy. PATIENTS AND METHODS: Between August 1, 1987 and July 15, 1995 138 (136 eligible) premenopausal patients with estrogen receptor (ER)- and/or progesterone receptor (PgR)-positive metastatic breast cancer were entered by the Southwest Oncology Group (SWOG), North Central Cancer Treatment Group (NCCTG), and Eastern Cooperative Oncology Group (ECOG). Prior chemotherapy or hormone therapy for metastatic disease was not allowed. Patients were randomly assigned to goserelin (3.6 mg subcutaneously every 4 weeks; (n = 69) versus surgical ovariectomy (n = 67). The study was initially designed as an equivalence trial with 80% power to rule out a 50% improvement in survival due to ovariectomy. However, accrual was slow and the study was terminated early, which resulted in a final power of 60% for the alternative hypothesis of equal survival distributions. RESULTS: FFS and OS were similar for goserelin and ovariectomy. The goserelin/ovariectomy death hazards ratio was .80 and the associated 95% confidence interval (CI) was .53 to 1.20. The test of 50% improvement in survival due to ovariectomy was rejected at P = .006. Goserelin lowered serum estradiol to postmenopausal levels. Hot flashes (75% v 46%) and tumor flare (16% v 3%) were more common with goserelin. CONCLUSION: Goserelin and ovariectomy resulted in similar FFS and OS. We can rule out a moderate advantage for ovariectomy. Goserelin was safe and well tolerated.

Adult↗

PubMed1997

Effect of ovariectomy in the early first half of the diestrus on induction or maintenance of canine deciduoma.

The effect of ovariectomy in the early first half of the diestrus was examined on the induction or maintenance of suture-induced canine deciduoma. Ovariectomy immediately, or some days, after the insertion of suture had no effect on the induction or maintenance of deciduoma. Even when ovariectomy was performed within 4 days before insertion, deciduoma could be induced in spite of there being no ovary. However, when ovariectomy was done 4 or more days before suture insertion, the rate of deciduoma was decreased or no deciduoma was induced. These results indicate that the influence of the ovary on the endometrium may persist for at least 4 days after ovariectomy. Ovariectomy after the suture insertion had few effects. It is suggested that canine uterine glands in the early first half of the diestrus maintain a certain degree of self-proliferative ability even after ovariectomy, and thus canine deciduoma is not as dependent on the ovary that of the rodentia.

Animals↗

PubMed2002

Is leptin a key factor which develops obesity by ovariectomy?

Withdrawal of estrogen by ovariectomy increases adiposity, but decreases the circulating levels of the ob gene product, leptin, which inhibits food intake. The reduction of circulating leptin levels may thus play an important role in the induction of obesity by ovariectomy. To examine this hypothesis, body weight change by ovariectomy was investigated in leptin-deficient genetically obese (ob/ob) mice with leptin supplement. Prior to the operation, obese (ob/ob) female mice were treated with intraperitoneal administration of recombinant mouse leptin (1.0 microg/g body weight/day) for 8 days. Then, half of the leptin-treated mice and their lean littermates were bilaterally ovariectomized and their body weight changes were observed for 56 days. From 16 days after the operation, a significant increase in body weight by ovariectomy was observed only in lean mice without leptin treatment. From 44 days, a significant body weight gain by ovariectomy was observed in leptin-treated obese mice. Ovariectomy significantly increased retroperitoneal white adipose tissue weight in their lean littermates, but not in leptin-treated obese mice. It was suggested that the reduction of circulating leptin levels may play an important role in the increases of acute phase body weight gain by ovariectomy, but during static phase, the direct effects of estrogen withdrawal may appear independent of leptin-mediated effects.

Adipose Tissue↗