Common bean protein hydrolysate modulates lipid metabolism and prevents endothelial dysfunction in BALB/c mice fed an atherogenic diet.

BACKGROUND AND AIMS: Common beans (Phaseolus vulgaris L.) protein hydrolysate is a source of bioactive peptides with known health benefits. The aim of this study was to evaluate the effect of common bean protein hydrolysate on lipid metabolism and endothelial function in male adult BALB/c mice fed an atherogenic diet for nine weeks. METHODS AND RESULTS: Male adult mice were divided into three experimental groups (n = 12) and fed with normal control diet; atherogenic diet and atherogenic diet added with bean protein hydrolysate (700 mg/kg/day) for nine weeks. Food intake, weight gain, lipid profile, Atherogenic Index of Plasma, inflammation biomarkers and endothelial function were evaluated. APH group presented reduced feed intake, weight gain, lipid profile, tumor necrosis factor-α, angiotensin II (94% and 79%, respectively) and increased endothelial nitric oxide synthase (62%). CONCLUSIONS: Protein hydrolysate showed hypocholesterolemic activity preventing inflammation and dysfunction of vascular endothelium, in addition to decreasing oxidative stress, indicating an adjuvant effect on reducing atherogenic risk.

Effects of the Booroola Fec gene on ovarian follicular populations in superovulated Romanov ewes pretreated with a GnRH antagonist.

Endocrine control of follicular growth was studied in mature Romanov ewes carrying (RF+) or not carrying (R+2) the Booroola Fec gene during an oestrous cycle after gonadotrophin-dependent follicles were suppressed by treatment with an antagonist of GnRH (Antarelix, 0.5 mg per day) and superovulatory treatment was administered. The left ovary was removed after 10 days of treatment (saline or Antarelix) and the right ovary was removed at the end of the superovulatory treatment. Ewes of both genotypes treated with Antarelix had lower plasma LH concentrations than did controls from day 0 to day 10. The inhibitory effect of Antarelix on LH concentration increased with day of treatment. The variability in FSH concentrations during the initial 10 days was reduced by Antarelix treatment in both genotypes. Plasma FSH concentrations were higher in RF+ ewes than in R+2 ewes. In both genotypes, FSH concentrations varied significantly with day of treatment, with the lowest concentrations at day 8 and the highest concentrations at day 5. RF+ ewes had a greater total and atretic number of antral follicles 0.62-1.12, 1.12-2.00 and 2.00-3.00 mm in diameter (classes 2, 3 and 4) than did R+2 ewes before and after superovulatory treatment. After superovulatory treatment, the total number of atretic and non-atretic follicles > 3.00 mm in diameter (class 5) increased in both genotypes. Superovulatory treatment also increased the number of total and atretic class 4 follicles in RF+ only. Conversely, superovulatory treatment decreased the mean number of class 3 follicles in both genotypes, while the number of atretic follicles was decreased only in R+2 ewes. Antarelix treatment significantly reduced the percentage of follicles > 2.00 mm in diameter in RF+ but not in R+2 ewes. Antarelix treatment before superovulatory treatment increased the total number of class 4 follicles in both genotypes but the increase was more significant in RF+ than in R+2 ewes. These results indicate that Antarelix pretreatment favours a greater superovulatory response in Romanov ewes carrying the Fec gene because ovulatory follicles are recruited from a wider range of follicular size classes.

Anastomosis of the ovarian vein to the hepatic portal vein in sheep induces ovarian hyperstimulation associated with increased LH pulsatility, but only in the absence of the contralateral ovary.

In this study, two experiments were performed, the first of which examined the ovarian response in ewes that were subject to unilateral ovariectomy (ULO) at different intervals (0-14 days) after surgical anastomosis (AN) of the ovarian vein to the mesenteric vein (n=7 ewes), or sham operation (SO; n=4 ewes). Hypertrophy and development of multiple follicular and luteal structures on AN ovaries were observed after ULO, while SO ovaries remained of normal size and appearance after ULO. The second experiment involving 11 ewes (five AN; six SO) aimed to clarify the mechanism by which AN following ULO-induced ovarian hypertrophy and increased follicle development. The results confirmed that there were more large (>5 mm) follicles on AN compared with SO ovaries; however, their rate of atresia was similar. Oestradiol and progesterone concentrations in follicular fluid of class 1 follicles (5-9 mm) were higher in AN ovaries than those in control follicles of the same size collected in the late follicular phase of an induced oestrous cycle. In AN ewes, intrafollicular progesterone concentrations increased while follicular aromatase activity and intrafollicular oestradiol, inhibin A, follistatin and activin A concentrations all decreased as follicle size increased. Oestradiol and progesterone concentrations were substantially higher in ovarian venous blood than in hepatic venous blood, both in AN and SO ewes, whereas inhibin A levels were not significantly modified by passage through the liver in either group. Mean plasma LH concentration, and LH pulse frequency and amplitude increased markedly after AN but were not affected by SO. Plasma FSH showed only a small transient increase after AN, presumably due to the maintenance of inhibin feedback. Injection of prostaglandin F(2)(alpha) 4 days later did not further modify LH or FSH secretion in either group. Full ovariectomy (FO) 9-14 days after AN or SO increased LH secretion markedly in SO ewes but to a lesser degree in AN ewes; FO induced a large and rapid increase in FSH levels in both groups. In conclusion, AN of the ovary to the liver via the mesenteric vein provides a useful model for studying the feedback between the ovary and the hypothalamo-pituitary system and the mechanisms controlling follicle development. The present results indicate that the pattern of LH secretion is an important factor controlling the terminal phase of follicle development in the ewe.

The effect of a GnRH agonist on follicular dynamics and response to FSH stimulation in prepubertal calves.

Endocrine control of follicular growth was determined by observing the left ovary of prepubertal calves previously treated with a potent GnRH agonist for 13 days. The ovarian response to hormonal stimulation was determined using the right ovaries of the same animals. Three-month-old crossbred calves were assigned to one of the two following treatment groups: 1) saline control for 13 days, with purified porcine FSH for the last 3 days (n = 5); and 2) GnRHa for 13 days, with purified porcine FSH for the final 3 days (n = 5). The left ovaries were removed from all calves after 10 days, and the right ovaries were removed at the end of treatment. Plasma concentrations of FSH, LH and oestradiol-17 beta were followed up during the GnRHa and pFSH treatments. The maximum macroscopic diameter of the F1 follicle, as determined by daily ultrasonography, did not differ between GnRHa-treated calves (from 6.6 to 10.4 mm) and the saline control calves (from 6.7 to 10.3 mm). Histological analysis of the ovaries showed that the number of follicles > 0.40 mm in diameter varied greatly for calves of the two groups (from 11 to 220 at 10 days). GnRHa significantly increased the mean number of follicles (total and nonatretic) of size class > 5.4 mm as compared to saline control calves (P < 0.05). The FSH treatment significantly increased the mean number of follicles 3.00-5.4 and > 5.4 mm in diameter (P < 0.05), with no change in the number of follicles smaller than 3.00 mm. The rate of atresia of large follicles (3.01-5.40 mm) was significantly reduced by purified porcine FSH treatment in both groups (P < 0.05). In no case did the GnRHa induce ovulation or luteinization of follicles. The LH and FSH concentrations increased transiently after GnRHa treatment on the first day, but afterwards, both hormones increased to only one sixth of what was observed after the initial GnRHa injection treatment. This increase in LH and FSH was observed 1 h after GnRHa treatment on each consecutive day of the experiment and were significantly different in the control group (0 h versus 1 h versus 2 h x saline control versus GnRH agonists groups; P < 0.01). During the superovulatory treatment, FSH concentrations peaked at around 0.70 ng.mL-1 in both saline- and GnRHa-treated groups on the first day but on the last day of surovulatory treatment, FSH concentrations were higher in GnRHa agonist-treated calves than in the control calves (day 11 versus day 12 versus day 13 x saline control versus GnRH agonist treatment groups; P < 0.01). LH profiles were unchanged by surovulatory treatment. Concentrations of oestradiol-17 beta increased significantly over the three days (P < 0.001) of the superovulatory treatments in both groups (P < 0.01). These results indicate that GnRH agonist treatment allows recruited antral follicles to pursue their growth during the early selection process via sustained FSH and LH secretion allowing more than a single large follicle to maintain their growth without going to atresia.

Reduction of the developmental competence of sheep oocytes by inhibition of LH pulses during the follicular phase with a GnRH antagonist.

A GnRH antagonist (Antarelix) treatment was used during the breeding season of Romanov ewes, to investigate whether LH pulses are required the day before the preovulatory surge for normal early embryo development in vivo (Expt 1) and in vitro (Expt 2). In Expt 1, at the onset of oestrus after removal of a fluorogestone acetate sponge, group A0.5 (n = 22) received a subcutaneous injection of 0.5 mg Antarelix, and ovulation was induced with an intravenous injection of 3 mg pig LH 24 h later. The control group (group C, n = 20) were untreated. All ewes were mated naturally at 36 and 48 h after oestrus and embryos were recovered 8 days after sponge removal. There were significant differences in the decrease in LH and in the increase in FSH concentration after Antarelix treatment between treated and control groups. The ovulation rate and embryo recovery rate were not significantly different between the two groups but the blastocyst rate was lower (P < 0.0001) in group A0.5 than in group C, with more unfertilized or degenerated oocytes in group A0.5 (69.2%). In Expt 2, 24 h after sponge removal, group A (n = 10) and group B (n = 10) received one subcutaneous injection of 0.5 mg Antarelix. The control group (group C, n = 10) was left untreated. LH pulsatility was re-established in group B with hourly intravenous injections of 5 micrograms ovine LH for 24 h. Oocytes were collected by flushing the oviducts 28 h after the LH surge, and were fertilized and cultured in vitro for 7 days. Ovulation and cleavage rates were not significantly different among the three groups but a higher rate of blastocysts (P < 0.01) was obtained after Antarelix treatment when LH pulsatility was re-established (group B). Oestradiol concentration was strongly depressed (P < 0.0003) after Antarelix treatment in group A, but was maintained after injection of LH pulses in group B, although at a lower value than before the preovulatory surge in the control group. In conclusion, inhibition of endogenous LH pulses 1 day before the preovulatory surge was not essential for ovulation and in vitro fertilization but was associated with a decrease in plasma oestradiol concentrations and inferior embryo development both in vivo and in vitro. When LH pulsatility was re-established, oestradiol concentrations increased and embryo development was restored.

Immunization of sheep against GnRH early in life: effects on gonadotropins, follicular growth and responsiveness of granulosa cells to FSH and IGF-I in two breeds of sheep with different prolificacy (Romanov and Ile-de-France).

The profile Romanov (R, ovulation rate = 3) and non-prolific Ile-de-France (IF, ovulation rate = 1) breeds were compared for their ovarian sensitivity to gonadotropins and IGF-I before puberty. For this purpose, the effects of in vivo immunization against GnRH on populations of ovarian follicles and in vitro sensitivity of granulosa cells to FSH and IGF-I were studied in prepuberal lambs from both breeds. Seventeen prepuberal lambs of each breed were actively immunized against GnRH between 3 wk and 6 mo of age. Relative to untreated lambs, FSH levels at 4, 5, and 6 mo of age were (respectively) 41%, 25% and 29% for IF, and 43%, 24%, and 36% for R lambs. In a first experiment, histological analysis of ovaries was performed. Immunization treatment decreased the number of small (100-390 microns in diameter) and large size follicles (< 1500 microns) in both breeds at 6 mo of age. In both breeds, gonadotropin (FSH-LH-hCG) treatment increased the number of large size follicles (< 1500 microns in diameter) and induced the formation of preovulatory follicles in immunized as well as untreated lambs. The ovulation rate was less in immunized animals, but it was not different between breeds. In a second experiment, the effects of FSH and IGF-I were studied on granulosa cells from follicles between 1000 and 2000 microns in diameter. In both breeds, IGF-I increased granulosa cell proliferation, but enhanced progesterone secretion was observed only in R lambs after FSH and IGF-I stimulation. Granulosa cell response to FSH treatment was lost by immunization, whereas response to IGF-I remained unchanged in both breeds. These results indicate that long-term immunization of prepuberal lambs against GnRH reduced systemic concentrations of FSH, follicular development, and response to gonadotropins in vivo, similarly in the prolific R and the non-prolific IF breed. However, granulosa cells from R lambs had higher steroidogenic capacities and were more responsive to FSH. In addition, these results suggest that IGF-I could play an important role in regulating growth of small follicles both in immunized and non-immunized lambs.

Anastomosis between ovarian and mesenteric veins in sheep: induction of a physiological hyperstimulation of the ovary.

Progesterone (P4) and estradiol 17 beta are essential for the dialogue between the ovary and the hypothalamohypophysial system. Immunization against steroids, although a valuable tool, displays limits. We propose a straightforward method to suppress steroids from the peripheral circulation by using the liver to catabolize steroids, through an anastomosis of the ovary to the mesenteric vein. Twelve mature cycling Ile-de-France ewes were unilaterally ovariectomized during the breeding season and subsequently randomly assigned to be anastomosed (n = 6; A) or sham-operated (n = 6; SO) on Day 10 of a synchronized estrous cycle. The ovarian vein was anastomosed to the superior mesenteric vein and all collateral veins to the ovarian vein were ligatured. Sham-operated ewes had only their collateral vein ligatured without anastomosis. Four days following surgery, ewes from both treatments were injected with PGF-2 alpha and autopsied between 9 and 14 days following surgery. Blood progesterone and estradiol 17 beta were measured daily from Day 4 before surgery until 7 days after castration. Estradiol levels measured at the level of the ovarian vein indicated that anastomosis allowed normal ovarian activity in all but 1 ewe in which collateral veins to the ovarian duct had developed. In the 5 A ewes, progesterone in peripheral blood decreased to low levels the day following surgery but this fall was not accompanied by an increase in estradiol. Estradiol levels measured at the output of the liver from hepatic vein were lower in A ewes (46.6 pg/ml) than in the ovarian vein of SO ewes (334.1 pg/ml). Ovarian hypertrophy was observed in 5 A ewes in which numerous large follicles were observed. These results indicate that the experimental model is functional and permits the study of the stimulation and hyperstimulation of the ovary and the control of the terminal follicular growth in the endocrine environment of the animal itself.

Follicular growth and ovarian dynamics in mammals.

General characteristics of female reproductive activity, such as seasonality, cyclicity and triggering of ovulation differ widely among mammals, but common mechanisms underlie ovarian function. In all mammals, follicles begin to grow from a pool of primordial follicles constituted early in life, continuously throughout the life of the female. Follicular development involves two phases. In a first phase (basal follicular growth), follicles grow slowly and follicular growth rate is tightly related to proliferation of granulosa cells. Basal follicular growth is mainly under the control of growth factors of paracrine origin. In these follicles, FSH may exert an indirect mitogenic effect on granulosa cells by enhancing expression of growth factors or growth factor receptors. In a second phase (terminal follicular growth), follicular growth is rapid and occurs by enlargement of the antrum. In addition, it is accompanied by important changes in differentiation of follicular cells. Terminal follicular development is strictly dependent on gonadotrophins. FSH plays determinant roles in enhancing granulosa cell differentiation and survival. These actions are mediated or modulated in an important way by paracrine factors, particularly steroids and growth factors. LH stimulates steroidogenesis in theca cells and sustains terminal maturation of granulosa cells in preovulatory follicles. Follicular growth, atresia and ovulation are accompanied by important tissue remodelling processes, which are under the fine control of proteinases and inhibitors of proteinases. In particular matrix metalloproteinases and their inhibitors are probably involved in the control of rapid terminal follicular growth and regression of atretic follicles as well as in follicular rupture at ovulation.

Hormonal induction of ovulation stimulates atresia of antral follicles in gilts.

Two breeds of prepubertal gilts known to differ in their ovarian development were used to compare the effect of hormonally stimulated ovulation on follicle numbers and proportion of follicular atresia in size classes other than preovulatory follicles. Hormonal treatments (hCG or eCG-hCG) were given to Meishan gilts (n = 36) at 3, 2, and 1 standard deviations (SD) before the mean age of puberty (51, 64, and 77 days of age) and to Large White gilts (n = 24) at 3 and 1 SD before the mean age of puberty (140 and 166 days of age). Ovarian follicle populations determined in the right ovaries 18 h after hCG injection alone (hCG) or 72 h after eCG injection (eCG-hCG) were compared with those in the left ovaries, which had been removed prior to injections. Follicles with dispersed cumulus cells around the oocytes (expected ovulations) observed after hormonal treatments (right ovaries) were considered for follicular measures and categorized into specific size classes according to their diameter. Human CG alone did not affect any follicular parameters measured at any age in either of the two breeds studied. The overall population of nonatretic follicles was significantly reduced by the eCFG-hCG treatment in the Large White breed when imposed at either 3 or 1 SD before the mean age of puberty (262.6 vs. 158.8; p < 0.01). Among the various follicle size classes studied, eCG-hCG treatment significantly decreased the mean number of follicles in size classes 2 (1.13-2.00 mm in diameter) and 3 (2.01-3.56 mm in diameter) at either 3 or 1 SD before the mean age of puberty in the Large White gilts (p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Comparative follicular development in Meishan and Large White gilts during prepubertal periods and its relation to hormonal stimulation.

Changes in follicular development in the left ovary and ovarian response to hormonal injections (hCG or eCG and hCG) in the right ovary were studied in Meishan gilts (n = 36) at 3, 2, and 1 standard deviations (SD) before the mean age of puberty (51, 64, and 77 days of age) and in Large White gilts (n = 24) at 3 and 1 SD (140 and 166 days of age). Left ovaries were removed at the time of hormonal treatments and the remaining ovaries were removed 18 h after hCG was injected alone (hCG) or 72 h after eCG was injected (eCG-hCG). Both nonatretic and atretic (> 4 pyknotic bodies) antral follicles > 0.6 mm in diameter were identified in the left ovaries by histological techniques. LH-sensitive follicles were identified in the right ovaries by counting follicles with dispersed cumulus cells around the oocytes. All large White gilts showed the presence of antral follicles at both 3 and 1 SD before puberty while 6, 7, and 12 Meishan gilts had antral follicles > 0.6 mm at 3, 2, and 1 SD before puberty, respectively. In Large White gilts, the mean number of nonatretic antral follicles > 0.6 mm remained constant at 3 and 1 SD before puberty, while in Meishan gilts, the mean number increased as gilts got older. Mean percentage of class 1 nonatretic follicles (0.6-1.12 mm) of the total number of nonatretic follicles increased significantly with age in Meishan gilts (p < 0.02), while those of class 3 (2.01-3.56 mm) decreased significantly (p < 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

[Control of terminal follicular maturation during the follicular phase in domestic mammals]. / Contrôle de la maturation terminale des follicules au cours de la phase folliculaire chez les mammifères domestiques.

Terminal follicular maturation in the ovine and the bovine species involves growth and differentiation processes in follicles between 1-2 mm diameter and the preovulatory stage. During this maturation, the follicle acquires the ability to ovulate and the oocyte becomes able to be fertilized and to develop after fertilization. Selection of ovulatory follicles results from the integration of different parameters such as the circulating levels of gonadotropins, the structure of follicular populations and the sensitivity of the hypothalamo-pituitary axis to ovarian hormones. Differences between follicles for FSH and LH responsiveness can be amplified by paracrine intrafollicular regulations. These mechanisms are probably determinant for selection of ovulatory follicles.

Proliferation of follicular cells and the effect of FSH on the onset of follicular growth in the ovary of 30-day old rabbits studied by continuous labelling with 3H-thymidine.

The ovary of the 30-d-old rabbit contains only small follicles with, at most, 3 or 4 layers of cells. We have estimated the labelling index of the follicular cells only from follicles having at least one labelled cell and using a zero truncated binomial distribution. The labelling index of the follicular cells of such follicles was weak and enlarged with the number of cells. It never exceeded 20%. Repeated injections of tritiated thymidine up to 8 times entailed a significant increase of the labelling index even for the smallest follicles. The labelling index of follicles was significantly increased 30 h after 1 injection of FSH (2 mg P-FSH). These results confirmed that the fraction of follicular cells that proliferate was low in the young rabbit ovary and the doubling time of the cells was large and that at this age, FSH increased the proliferation of cells.

Trichostrongylus colubriformis: epithelial cell migration in the proximal and distal small intestine of infected rabbits.

In Trichostrongylus colubriformis-infected rabbits, epithelial cell migration rates and cell transit times along the villi were compared by radioautography on histological slides to normal values from noninfected small intestine. Regions of gut with high (upper jejunum) and low (ileum) burdens of worms were both examined. In the control rabbits, the estimated values for the cell migration rates in the proximal and distal parts of gut were respectively 5.8 and 2.8 microns/hr. Seventy-two hours after the thymidine injection, the labeled epithelial cells were near the tip of the villi in the jejunum whereas only 60% of the villous length was labeled in the ileum. In the infected rabbits, the presence of T. colubriformis was associated with a two-fold increase of the cell velocity, in the main site of infection. Although less prominent than in the proximal region, a significant acceleration in the cell migration was also noticed in the ileum. The cell transit time was markedly reduced in the parasitized jejunum, but no variation of this parameter was found in the distal part of gut. These changes in the dynamics of epithelial cells in both regions of the gut appeared to underlie the morphological and enzymological changes of the parasitized mucosa. They particularly contribute to create an adaptive region in the small intestine beyond the main site of infection.

[Effect of genotype, age and season on preovulatory follicles in the rabbit 8 hours after mating]. / Effet du génotype, de l'âge et de la saison sur les follicules préovulatories de la lapine 8 heures après la saillie.

The purpose of this study was to compare the population of preovulatory follicles in two INRA strains of rabbits of different natural ovulation rates. The two strains chosen were the Californian (A1066) with an ovulation rate of 13 and the New Zealand (A1077) with an ovulation rate of 11. Nulliparous, primiparous and multiparous does were followed during the four seasons. Eight hours after mating the right ovaries of 154 of these animals were collected. The following data were recorded : the number of follicles with an area equal to or more than 5.10(5) micron 2 (diameter : 0.8 mm), the area of that section of the follicle containing the oocyte, and the presence of pyknotic cells with granulosa. The higher ovulation rate of Californian does was due to a significantly higher number of healthy follicles. The mean size of these follicles, their area (between 5.10(5) micron 2 and 3.10(6) micron 2) distribution and rate of atresia were similar in the two strains. Environmental factors led to changes in the number and size of healthy follicles which were responsible for the number of ovulations, while the rate of atresia remained constant. The seasonal effect was most marked in November by a definite reduction in follicle size, particularly in multiparous does. Follicle number and size increased with parity number; this seemed to be due to an acceleration of the growth rate and to the increasing number of large-sized follicles. As there were no interactions between genotype and environmental factors, it can be concluded that the latter modified follicular growth parameters in the same way in both strains and that these strains can be identified in all cases on the basis of their ovarian characteristics. About 1/3 of the does exhibited almost exclusively healthy follicles, while in the remaining 2/3 both healthy and atretic follicles were seen. These proportions were the same in both female genotypes. Those possessing only healthy follicles also had the largest ones. It is suggested that atresia could be a regulatory factor of ovulation rate along with the preovulatory level of FSH. 23% of the does accepting the buck showed no oocytes in meiosis, even though their follicle size exceeded 5.10(5) micron 2. Th mean number of these follicles was the same as that of does with oocytes in meiosis, but they were half as large. It is suggested that the follicle oestrogen secretion of these does was not high enough to induce ovulatory release of LH at mating.

Ovarian follicular growth during the oestrous cycle in two breeds of ewes of different ovulation rate, the D'Man and the Timahdite.

The population of growing follicles of diameter greater than 60 micron was studied in 24 D'Man and 24 Timahdite ewes aged 2-2.5 years. The ovaries of each ewe were removed on Days 1, 2, 3, 4, 5, 7, 9, 11, 13, 15 or 17 of the oestrous cycle. Two ewes from each breed were ovariectomized. The mean ovulation rate was 2.9 in D'Man and 1.1 in Timahdite ewes and the mean numbers of normal follicles were 276 and 230 respectively. The distribution of the various sizes of follicles did not differ significantly between the two breeds. However, the number of follicles of diameter 118 to 462 micron (follicles beginning to develop an antrum) and the number of follicles of diameter greater than 1285 micron (large follicles possessing an antrum) were significantly greater in the D'Man than in the Timahdite ewes (136 and 106, and 7.1 and 4.5, respectively). The mean number of atretic follicles was similar for the two breeds (13.3 in the D'Man; 12.2 in the Timahdite), but in the D'Man there was a lower rate of atresia (54.9 compared with 66.7%) for follicles of 1084-2141 micron diameter. During the first days of the cycle there was a significant decrease in both breeds in the number of follicles of 60-118 micron diameter. During this same period there was a significant decline in the number of follicles of diameter 119 to 462 micron but in the D'Man ewes only. Therefore, the higher ovulation rate of the D'Man breed is due to the greater number of those follicles from which ovulatory follicles are recruited.

FSH, LH and prolactin levels, ovarian follicular development and ovarian responsiveness to FSH in the Snell dwarf mouse.

The homozygous Snell dwarf mouse is sterile. It has been shown that pituitary hormone levels are low in 3 month old animals except for FSH and LH whose pituitary contents and plasma concentrations are normal. In this study, the pituitary FSH, LH and prolactin (Prl) content, the FSH plasma concentration and the ovarian follicular development of the Snell dwarf mouse were studied at 18, 20, 24, 40 and 80 days of age. Normal mice were also studied at the same age and served as controls. Pituitary FSH was significantly lower in dwarf mice compared with controls during the period days 18 to 30, while plasma FSH was significantly lower during the period days 20 to 80. Pituitary LH was significantly lower in dwarf mice during the period days 18 to 40. In normal mice, pituitary Prl increased with age, but remained consistently low in dwarf mice. The normal number of growing follicles was similar in dwarf mice and controls up to day 30, but thereafter the total number of growing follicles was greater in the controls. In the dwarf mice, the production of antral follicles was low and there were no ovulations. The rates of atresia were similar in the two genotypes. The responsiveness of the dwarf mouse ovary to FSH was then examined. When dwarf and control mice were supplemented with FSH for 5 days starting at 24 days of age, the ovarian and uterine weights increase 6- and 5-fold, respectively, in the dwarf mice, and 2- to 3-fold in the normal mice.(ABSTRACT TRUNCATED AT 250 WORDS)

Action of PMSG on follicular populations in the heifer.

The short-term action of PMSG on the population of growing follicles in cattle was studied using histological methods. On Day 7 of a synchronized oestrous cycle 10 Friesian heifers were unilaterally ovariectomized. The remaining ovary was immediately stimulated by an injection of PMSG (2000 i.u.) and was removed 48 h after the preovulatory discharge of LH. Control animals did not receive any injection of PMSG. In all ovaries, follicles greater than 70 micron diameter were counted, measured and checked for atresia. The mitotic index in granulosa cells of follicles of different sizes was estimated in both ovaries of all the PMSG-injected animals. Unilateral ovariectomy alone had no significant effect on follicular populations. In the interval between PMSG injection and removal of the second ovary (148 +/- 22.7 h), PMSG significantly increased the number of normal preantral follicles but did not change the number of normal antral follicles. The mitotic index doubled in preantral and early antral follicles but remained unchanged in large antral follicles. PMSG stimulated slightly the growth of the antrum in large antral follicles but did not stimulate its formation in preantral follicles. The incidence of atresia among antral follicles, particularly the largest ones (diam. greater than 1.7 mm), was significantly reduced after PMSG, suggesting some 'rescue' of follicles from atresia.

Hormonal levels after ovarian X-irradiation of ewes.

This paper reports the effects of X-irradiation on ovulation rate, cyclicity and progesterone and FSH levels in Ile-de-France ewes (4 control and 16 irradiated) after they were treated during the breeding season. The doses used (800 and 2 400 R) destroyed 50% of all size classes of the follicular population. Ovulation occurred in 87% of the treated ewes (ovulation rate = 1) when they were irradiated 24 h after luteolysis; 78% of the corpora lutea resulting from these ovulations were normal as to length and progesterone production. FSH in treated ewes started to increase 20 h after treatment and remained higher than in the controls until ovulation time. Later, while these levels were similar between groups on the day of ovulation, high ovulatory levels persisted in irradiated ewes. In the next cycles, the length of the follicular phases, ovulation rate and progesterone and FSH levels were similar between groups.

Seasonal effects on ovarian follicular development in pony mares.

To define ovarian follicular kinetics in the equine ovary during anestrus and the breeding season, the follicular population of pony mares was investigated at mid-anestrus and at the beginning and end of the breeding season. There was a clear effect of season on the exit of reserve (primordial and initiated) follicles since at the beginning of the breeding season we noticed a higher mitotic index for the smaller preantral follicles, leading to an accumulation of small and medium antral follicles. In contrast, the ovaries sampled during anestrus or at the end of the breeding season were very similar; only preovulatory development was lacking in anestrous ovaries. However, atresia was unaffected by season.

Anomalies in ovarian function of peulh ewes.

The ovarian activity of 8 Niger Peulh ewes was followed for 2 1 2 years by assaying the levels of progesterone in blood plasma sampled daily and by endoscopic observation. Although the ewes did not experience seasonal anestrus, their cycles were not regular. Most animals had persistent corpora lutea at some stage, but particularly in June. This resulted in cycles averaging 49.9+/-6.8 days in length instead of the normal 16.9+/-0.1 days. Intervals between successive luteal phases lasted 4-15 days as compared with 2.3+/-0.06 days seen in normal cycles. This occurred in most ewes at least once during the period from December to April. In these cases, the preovulatory discharge of LH was delayed until 7.5+/-1.8 days after the fall in the level of progesterone. The incidence of these anomalies suggests that the ewes had 69% of the ovulations and 56% of the behavioral estrus as compared to ewes that cycled regularly.