Anti-Müllerian hormone (AMH) secretion in prepubertal and adult rams.

The aim of the present analysis was to determine whether anti-Müllerian hormone concentrations in prepubertal plasma or adult rete testis fluid are related to the number or function of Sertoli cells in rams or to the presence of the FecB Booroola gene. Twenty rams from two Booroola crosses, differing in their testicular masses were analysed; in each cross, half of the animals were heterozygous carriers of the FecB gene. The data from rams, during prepuberty and at adulthood during the non-sexual season, were analysed by two-way ANOVA and residual correlations.

Localization and quantification of melatonin receptors in the diencephalon and posterior telencephalon of the sheep brain.

In an attempt to better understand the mechanisms by which melatonin controls neuroendocrine activity, we tried to define with accuracy the brain areas where the density of melatonin receptors is the highest in sheep and to establish their characteristics. The specific labelling of 125I-melatonin was first revealed by autoradiography on brain sections of the posterior telencephalon and diencephalon in three ewes. The extent and position of the five structures where the binding was found to be the highest (i.

Effects of an LH-RH agonist on reproductive responses and endocrinological parameters in landais ganders.

Semen quantitative (sperm production) and qualitative parameters (percentage of live and normal spermatozoa, sperm motility, egg fertility and hatchability), as well as hormonal parameters (LH and testosterone plasma concentrations) were compared for landais ganders, which were treated or not, with an LH-RH agonist prior to being sexually active. Treatment with the LH-RH agonist at this physiological stage delayed the onset of sperm production in some of the treated males. Although, comparable data were obtained during the first half of the reproductive period, treatment with the LH-RH agonist maintained sperm output at higher levels during its second half.

Changes in LHbeta-gene and FSHbeta-gene expression in the ram pars tuberalis according to season and castration.

Luteinizing hormone beta (LHbeta) and follicle stimulating hormone beta (FSHbeta) subunits and their mRNAs were studied in the ram pars tuberalis following different seasonal (winter vs summer) and experimental (intact vs castrated animals) conditions. Hormone-containing cells were identified by immunohistochemistry, using homologous double-stranded 35S-cDNAs. The labelling was quantified by image analysis.

Effect of thyroxine on testicular function, circulating luteinising hormone and pituitary sensitivity to luteinising hormone-releasing hormone in the cockerel (Gallus domesticus).

1. The effect of thyroxine (T4) on reproductive function in the adult cockerel was followed for 11 weeks. Broiler cockerels aged 96 weeks were fed on diets containing either 0, 2 or 5 mg T4/kg for 4 weeks.

Induced moulting in cockerels: effects on sperm production, plasma concentrations of luteinising hormone, testosterone and thyroxine, and on pituitary sensitivity to luteinising hormone-releasing hormone.

1. The ability of a moult-inducing procedure to restore high levels of sperm production was assessed, in two experiments, using cockerels with reduced sperm production. The moulting procedure consisted of a period of food and light restriction for 6 weeks.

Comparison of various characteristics of duration of fertility in hens.

1. Maximum duration (Dm, number of days post-insemination until last fertile egg) and efficient duration (De, number of days post-insemination until first infertile egg) of fertility, number of fertile eggs (F), dead embryos and hatched chicks (H) during the 21 d following the latter of two intravaginal inseminations (with 125 x 10(6) spermatozoa) on two consecutive days were measured in a total of 2549 layer-type hens at three ages (starting at 30, 44 and 55 weeks of age). 2.

Effect of different fractions of seminal plasma on the fertilizing ability of fowl spermatozoa stored in vitro.

This paper describes the effects of whole seminal plasma and of dialysed seminal plasma on the fertilizing ability of fowl spermatozoa stored for 24 h at 4 degrees C. The fertilizing ability of fowl semen diluted 1:1 with Beltsville Poultry Semen Extender and stored for 24 h at 4 degrees C was enhanced after replacement of the homologous seminal plasma by the diluent (89 versus 77% fertilization rate). Better results were obtained with seminal plasma dialysed against water before sperm storage to discard the less than 1 kDa or the less than 50 kDa fractions.

Localization of luteinizing hormone beta-mRNA by in situ hybridization in the sheep pars tuberalis.

The localization of luteinizing hormone beta (LH beta)-mRNA was studied by in situ hybridization in the pars tuberalis of sheep using a homologous sheep double-stranded 32P- or 35S-cDNA. The labelled cDNA probe detected one mRNA sequence in the pars tuberalis by Northern blot analysis; this sequence was similar to that detected in the pituitary. In situ, the labelling of LH beta-mRNA in the horizontal and sagittal tissue sections was found throughout the pars tuberalis.

Melatonin binding sites in the brain of sheep exposed to light or pinealectomized.

The binding sites of [125I]melatonin were identified in the sheep brain using a specific and sensitive autoradiographical method. Rams were either untreated (controls) or exposed to light before slaughter or pinealectomized (px). In all animals labelling was intense in the pars tuberalis (PT) and absent in the suprachiasmatic nucleus (SCN).

Characterization of melatonin receptors in the ram pars tuberalis: influence of light.

The present study was conducted to assess the binding of [125I]melatonin to frozen unfixed sections of pars tuberalis/median eminence tissue from Ile-de-France rams exposed or not exposed to light before slaughter. The specificity of [125I]melatonin binding to the pars tuberalis tissue was revealed by autoradiography and the magnitude of binding as related to the pars tuberalis area was determined after incubation and counting of pars tuberalis/median eminence sections. Subsequent studies with sections incubated with [125I]melatonin indicated that 1.

The sheep pars tuberalis: an immunohistochemical study. Demonstration of the presence of glycoprotein and lipotropin hormones.

Using indirect immunofluorescence with fourteen different antisera raised against pituitary hormones and peptides, we characterized immunochemically the cells of the sheep pars tuberalis. The presence of LH- and FSH-containing cells, shown in previous studies, was also observed in the present investigation. In addition, we found TSH-containing cells, never observed in sheep, and beta LPH-containing cells.

Melatonin binding sites in the sheep pars tuberalis.

The localization of [125I]melatonin binding sites has been studied by autoradiography on frozen unfixed sections of the pituitary stalk, the suprachiasmatic area, the pineal and the pituitary glands in sheep. Dense specific labelling has been found exclusively in the pars tuberalis of the pituitary stalk but not in the part of the median eminence surrounded by the pars tuberalis. The labelling was completely excluded by a 200-fold excess of cold melatonin.

Expression of several traits of fertility in young and old dwarf broiler breeder hens inseminated with duplicate doses of semen.

One hundred sixty-two dwarf broiler breeder females were each inseminated at 4-wk intervals with either 30, 60, or 120 million spermatozoa repeated on 2 consecutive days. The experiment was conducted at two age periods, i.e.

Quantitative autoradiographic study of FSH binding sites in prepubertal ovaries of three strains of rats.

Iodinated FSH was injected to 18- and 36-day-old rats of 3 strains (03, 04 and 12) with different sensitivity to FSH (12 less than 03 less than 04) and autoradiography was performed on histological sections of the labelled ovaries. Specific labelling was quantified by microphotometry on histological slides, on granulosa cells of individual follicles with different sizes (greater than 80 micron diameter) and qualities. In small preantral follicles (less than 160 micron diameter) the labelling was low and homogeneous within the granulosa; it increased between 18 and 36 days of age in the 3 strains.

Sequential effects of FSH on the first stages of ovarian follicular development in normal and dwarf Snell mice.

The population of small growing ovarian follicles was divided into 4 classes according to the number of granulosa cells (from 15 to 95) surrounding the oocyte, and a comparison was made of normal and dwarf mice. Follicular cell proliferation was estimated by tritiated thymidine incorporation. In normal mice, most follicles in classes 1 (15 to 35 granulosa cells in their largest cross-section) and 2 (36 to 55 cells) were labelled (86 and 95%, respectively); FSH treatment increased the labelling index (L.

Testicular growth and hormonal parameters in the male Snell dwarf mouse.

Dwarf mice show delayed testicular growth and their adult testis weights are half the normal value. The aims of the present work were firstly, to compare the developmental profiles of plasma gonadotropins and of testicular cell multiplication and differentiation in dwarf vs normal mice and secondly, to determine the effect of hMG supplementation on dwarf mice. In the dwarf mice no pubertal rise in plasma FSH was observed, and the adult values remained very low when compared with those of normal mice; plasma LH decreased after 40 days of age and remained equal to half the normal values.

Hemiovariectomy and follicular growth in the immature rat.

Female rats were hemiovariectomized on day 1 (T2) or day 10 (T3) after birth. The population of growing follicles in the remaining ovary and the plasma levels of FSH an LH were compared to controls (T1) on post-natal days 20, 30 and 38. There was a non significant trend towards higher FSH and LH levels in hemicastrates.

Quick freezing of rat embryos.

Quick freezing of rat morulae and blastocysts was attempted after they were dehydrated at room temperature. Combined solutions of 2.8 M glycerol and 0.

Testis development and daily sperm output in guineas submitted to progressively increasing daily photoperiods at different ages.

Four hundred and eighty guineas were raised under short days (7L:17D) from 3 weeks of age, then subjected to increasing light at 8, 16, 20, or 24 weeks of age. After receiving 7 additional hours of light (+ 1 hr per week) for each of 7 consecutive weeks, each group was then maintained on long days (14L:10D) until 70 weeks of age. No significant differences were observed between photoschedules for growth rate or adult body weight; however, the age at which the daylengths were increased greatly influenced the development of the testes and daily sperm output (DSO).

[Partial abolition of seasonal variations of testicular weight in rams by decreasing the photoperiod].

Under moderate latitudes all breeds of rams undergo seasonal variations in testicular weight with a maximum during summer under decreasing daylength ([1]-[4]). Similarly, in rams submitted to a 6-month artificial light regime [5] or to an alternation of long (16L:8D) and short (8L:16D) days [6] an increase in testicular weight occurred following a decrease in daylength and vice versa. However this effect is transitory, a phenomenon which can be referred as photorefractoriness.

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.

[Biological control of the brucellin INRA in sensitized guinea pigs: a guide for the statistical analysis of results].

Brucellin INRA is a new allergen used for the screening of brucellosis. It shows, by a delayed-type skin hypersensitivity reaction, the sensitization induced in animals by a brucella infection. The biological potency of each batch must be compared to that of a standard allergen.

Diurnal variation in release of LH and testosterone in the ram.

The time of appearance of plasma LH and testosterone peaks through the day determined in 75 Préalpes du Sud and 41 Ile-de-France rams in December and in 44 Préalpes du Sud and 11 Ile-de-France rams in June. The distribution of peaks throughout the day was non-random for the two hormones in the two breeds and for both times of the year (P less than 0.01 at least on each occasion; P less than 0.

Seasonal variation in LH and testosterone release in rams of two breeds.

Blood was collected hourly for 24 h in December, February, April, June and September from Préalpes du sud and Ile-de-France rams. Coincidence of the LH and testosterone peaks was found for 96.4% of a total of 670 LH peaks and 647 testosterone peaks.