Characterization of the fertility of Kit haplodeficient male mice.

The role of the proto-oncogene Kit expression during gonadal development, then in differentiated spermatogonia has been thoroughly established. The present study was designed to investigate the consequences of a partial defect in Kit gene expression on sperm fertilizing ability, using Kit haplodeficient mice (kitW-lacZ/+). Same inbred mice (kit+/+) were used as controls.

Apoptosis, onset and maintenance of spermatogenesis: evidence for the involvement of Kit in Kit-haplodeficient mice.

Kit/stem cell factor (SCF ) has been reported to be involved in survival and proliferation of male differentiating spermatogonial cells. This kinetics study was designed to assess the role of Kit/SCF during spermatogenesis in mice, and the extent of male programmed germ cell death was measured between 8 and 150 days of age. For this purpose, 129/Sv inbred mice in which one Kit allele was inactivated by an nlslacZ sequence insertion (Kit(W-lacZ/+)) were compared with 129/Sv inbred mice with wild-type alleles at the Kit locus.

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.

Effects of the Booroola gene FecBB on somatic and germ cells of the fetal testis.

The present study was conducted to compare in homozygous FecBBFecBB(BB) Booroola and ++ male fetuses, the body and the testicular growths and the tissular and cellular compositions of the testis between 60 and 140 days of gestation. To eliminate differences in growth due to uterine environment, single embryos have been transferred in recipient Mérinos d' Arles ewes. At 60 and 100 days of gestation, the body masses of BB fetuses were significantly lower than those of ++ foetuses (11 and 13%; P = 0.

Proliferation and differentiation of porcine inner cell mass and epiblast in vitro.

The proliferation rate and differentiation state were investigated in porcine inner cell masses (ICMs) and epiblasts in vitro. ICMs isolated from early blastocysts (Day 7 of pregnancy) and epiblasts isolated from preelongated blastocysts (Day 11 of pregnancy) were cultured for up to 5 days in the presence of human leukemia inhibitory factor (hLIF) (1000 U/ml). The proliferation rate was evaluated by determination of the percentage of cells in S-phase.

Induced differentiation of ovine foetal gonocytes after grafting in the scrotum of nude mice.

This work was designed to elucidate, in foetal ovine testis, whether the reason why gonocytes do not differentiate into spermatogonia and do not initiate spermatogenesis is due to inadequate foetal environment (temperature and/or hormonal balance) or if somatic testicular cell proliferation is a prerequisite for initiation of male meiosis. The development and differentiation of gonocytes were analysed by grafting 60-day-old foetal ovine tests into the scrotum of immunotolerant adult Nude mice. Forty days after grafting, nine of the ten grafted testes had survived but had not increased in weight as compared to 60-day-old tests.

Evidence for germ cell control of Sertoli cell function in three models of germ cell depletion in adult rat.

In order to clarify the role of germ cells in the regulation of Sertoli cell secretions, three experimental models of germ cell depletion were used: hypodactyl rat mutation (testis weight [TW]: 55% less than controls), in utero busulfan treatment (TW: 88% less than controls), and neonatal experimental cryptorchidism (TW: 72% less than controls). The aim of this work was to compare the numbers of Leydig and Sertoli cells and the production of germ cells in each experimental model to the in vitro secretions of Leydig and Sertoli cells in conditioned media and to the hormonal serum profiles of the same animal in vivo. In the three models, serum levels of hypophyseal and testosterone hormones were significantly increased and decreased, respectively.

Evolution of somatic and germ cell populations after busulfan treatment in utero or neonatal cryptorchidism in the rat.

In order to elucidate the respective effects of depletion of germ cells and of increase in testicular temperature, rats of the same Wistar strain were rendered experimentally bicryptorchid or sterilized by a busulfan injection in utero and compared to control animals. In both models, germ cells were depleted but numeric evolution and functions of somatic cells differed. The aim of that work was to compare the numeric evolutions of testicular somatic and germ cells to their respective functions in each model before puberty and in adult rats of the same strain.

Effect of short photoperiodic cycles on male genital tract and testicular parameters in male goats (Capra hircus).

This study was performed in adult male goats in which seasonal variations were abolished by rapid alternations of long days and short days. These treatments have been shown previously to prevent seasonal changes in the hypothalamo-pituitary axis and to maintain testis weight and sperm production at a high level. The experimental groups were exposed for 3 years to an alternation of either a 1 month short (16 h dark; 8 h light) and 1 month long (16 L; 8 D) photoperiod (2 month cycle; n = 5) or of a 2 month short and 2 month long photoperiod (4 month cycle; n = 4).

Ontogenesis of somatic and germ cells in sheep fetal testis.

Testicular development of sheep fetuses was studied between day 42 of gestation and birth. Testis mass and the total number of testicular cells increased curvilinearly with fetal age and a positive linear relationship was established between the logarithmic values of age and testis mass, sex cord total length, total number of Sertoli cells, germ cells and Leydig cells per testis. The mean number of gonocytes per unit length of sex cord, the Sertoli cell nuclear cross-sectional area and the Leydig cell cross-sectional area decreased linearly with age between day 42 of gestation and birth.

Effects of a single brief period of moderate heating of the testes on seminiferous tubules in hypophysectomized rams treated with pituitary extract.

An experiment was conducted to examine the appearance of the seminiferous tubule 20 days after a single exposure of the testes of rams to a scrotal temperature of about 42 degrees C for 45 min. Ten of the animals were surgically hypophysectomized and five were simultaneously heated; these rams were treated twice a day with ovine pituitary extract to avoid modifications in the negative feedback from the testes to the pituitary and consequent changes in gonadotrophin secretion. Six intact rams (three heated and three unheated) were also studied.

[Pathogenic effects of Trypanosoma congolense on the testis of Baoulé bulls: quantitative and morphometric histology].

The effect of Trypanosoma congolense on testis was studied in 53 trypano-resistant "Baoulé" bulls by quantitative histology and morphometry. The daily spermatozoa production per testis of control groups (n = 45) was 382 +/- 334 x 10(6) (m +/- sd) and the epididymis contained 0.6 +/- 1 x 10(9) spermatozoa in the caput, 0.

In vitro culture of embryonic disc cells from porcine blastocysts.

The aim of the present study was to define the conditions of preparation and in vitro culture of embryonic discs allowing proliferation of ES-like cells. G5-6 porcine blastocysts (G0 = day of AI) were cultured in toto; in G10-11 blastocysts, trophectoderm and primitive endoderm were microsurgically removed from embryonic discs (ED) which were cultured either on plastic or on a feeder layer. Feeder cells were foetal G30 porcine fibroblasts which had been previously irradiated.

Germ cell-Sertoli cell interactions and production of testosterone by purified Leydig cells from mature rat.

The addition of seminiferous tubule (ST) culture medium (STM) prepared from testes of either busulfan-treated (Bus) or cryptorchid (Cryp) or genetically sterile (hd) rats, to Percoll purified Leydig cells leads to a further increase of LH-stimulated testosterone (T) output (26, 43 and 14%, respectively). Taking into account that the Sertoli cell number per cm of ST is 2.6, 1.

Effect of a 2-month light cycle regimen on testicular parameters of adult Ile-de-France rams.

This experiment was conducted in Ile-de-France adult rams to examine the target point of a 2-month light cycle regimen on seminiferous tubule functions, on intertubular compartment and on Leydig cell parameters. Eight rams were subjected to a 2-month light cycle regimen and were compared to sexually active or inactive rams. In light-treated rams, testis weight was maintained equal or was higher than that of sexually active rams.

The form and function of the Leydig cells in hypophysectomized rams treated with pituitary extract when spermatogenesis is disrupted by heating the testes.

The morphology and in-vivo function of the Leydig cells were studied in rams when spermatogenesis had been disrupted by a single exposure of the testes 20 days earlier to a temperature of about 42 degrees C for 45 min. To avoid complications due to changed negative feedback from the testes to the pituitary with consequent changes in the degree of gonadotrophic stimulation, ten of the animals (five heated and five unheated) were surgically hypophysectomized when the testes were heated and then treated twice daily with pituitary extract. Six intact rams (three heated and three unheated) were also studied.

Age-related changes in the function of the pituitary-gonadal axis in a sterile male rat mutant (hd/hd).

Testicular growth is depressed in the genetically sterile male rat (hd/hd) relative to its LE phenotype littermates (by 50% and 73% at 27 and 90 days of age, respectively). Within the hd/hd testis, both the tubular and seminiferous tubule tissues are affected by the mutation. In addition, there is significantly less germ cell production from the primary spermatocyte stage of spermatogenesis onwards and the total number of Sertoli cells observed is less.

Evidence for LH-inhibiting activity in ovine peripheral and testicular blood.

Intracellular cyclic AMP and testosterone productions by purified mature rat Leydig cells were stimulated by oLH (25 micrograms/l) 18- and 12-fold, respectively, after a 5-h incubation period. The replacement of the incubation medium by charcoal-treated testicular venous plasma (40%, v/v) from adult rams in the breeding season induced an inhibition of cyclic AMP and testosterone productions (82 and 66%, respectively, of oLH-stimulated values). Testicular arterial plasma is less effective than testicular venous plasma, even when it originates from non-breeding season rams; in that case, testicular venous and arterial plasma strongly inhibit testosterone productions (84 and 67%, respectively of oLH-stimulated values), which probably indicates that the inhibitory activity is higher in the non-breeding season.

Comparisons of endocrinological and testis parameters in 18-month-old Ile de France and Romanov rams.

Endocrinological and testis parameters of adult 18-month-old Ile de France (IF) and Romanov (Ro) rams were compared during sexual season. Testis weights, total volumes of intertubular tissue, and of blood and lymph vessels, total seminiferous tubule length, rete testis flow rate and daily production of germ cells were significantly higher in IF than in Ro rams. These variations originated from differences in Sertoli cell numbers, which were established before puberty.

[Demonstration of LH inhibitor(s) in sheep and human sera].

In mature rat Leydig cells, the testosterone output (24 ng/10(6) Leydig cells/4hrs.) is increased 10 fold by LH; the addition of serum from either control or castrated or hypophysectomized rams inhibits (60%) the LH-stimulated testosterone production. Similarly, the incubation of immature rat Leydig cells with sera from hypophysectomized patients leads to a diminution (70 and 30% respectively) of both basal (0.

Changes in androgen binding protein (ABP) production following continuous low dose gamma irradiation (IR) of adult rat.

Continuous low dose gamma irradiation induces a progressive degeneration of germ cells with a concomittant increase in blood FSH; however, the Sertoli cell function is not too much altered since serum ABP level is normal and it is likely that the decrease of epididymal ABP content is the consequence of a reduction in seminiferous tubule fluid excretion. Obviously, spermatids seems to be involved in the regulation of Sertoli cell ABP synthesis.

Endocrine parameters, hormone receptors, and functions of the testicular interstitium and seminiferous epithelium in estradiol-immunized Ile-de-France rams.

The testicular response of Ile-de-France rams actively immunized against estradiol (E2) was evaluated during both the ovine nonbreeding season (spring) and breeding season (autumn). Plasma concentrations of LH, FSH and testosterone were elevated in E2-immunized rams during both spring and autumn when compared with BSA-immunized controls. Testis weights were significantly elevated by E2 immunization and were characterized by greater interstitial cell volume, including Leydig cells, blood and lymph vessels, greater seminiferous tubule length, and greater numbers of leptotene spermatocytes and round spermatids.

Effect of continuous low-dose gamma-irradiation on rat Sertoli cell function.

Continuous low-dose gamma-irradiation of mature rats induced a progressive degeneration of the germ cells. Blood FSH increased by 127, 176 and 214%, respectively, after 55, 70 and 85 days of treatment when compared to FSH levels in control rats (8.50 +/- 0.

[Comparison of plasma levels of the gonadotropic hormone FSH, during the first 3 months of life, in male lambs, carrying or not carrying the "F" gene of proliferation].

We have found evidence in the male lambs, Booroola x Mérinos d'Arles and Booroola x -Romanov, during the first three months of life, for the expression of the "F" prolificacy gene. More FSH at the peripheral plasma levels is observed in males carrying one copy of the "F" gene as compared to non carriers of the same crosses in the same environment. However the difference is of too small amplitude to be utilised to discriminate male lambs carrying the "F" gene.