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C Perreau

Publications and source records attributed to C Perreau.

48 records · Page 3Linked to original sources
PubMed1982

Effect of cryptorchidism in the ram: changes in the concentrations of testosterone and estradiol and receptors for LH and FSH in the testis, and its histology.

Cryptorchidism was induced in 5 pre-pubertal lambs and 7 adult rams, 5 months after surgery, testicular weight and membrane protein content were 4-fold lower than in the control. The total number of Leydig cells per testis was markedly decreased but their size was not changed. In contrast, the total number of Sertoli cells per testis was not affected but their nuclear size was smaller. Induced cryptorchidism had no effect on the length of seminiferous tubules; blood vessel volume was reduced; and the production of germ cells was completely disrupted. The number of LH receptors estimated per Leydig cell was not changed in pre-pubertal lambs but decreased 4-fold in adult rams. The number of FSH receptors calculated per Sertoli cell was reduced by 95% in both pre-pubertal and adult animals. No effect on the binding affinities of LH (Ka = 1 X 10(10) M-1) and FSH (Ka = 4.5 X 10(9) M-1) to their testicular receptors was observed. Although testicular concentrations of testosterone and estradiol-17 beta were increased, the total content of testosterone within the testis was increased only in pre-pubertal lambs. The estimated ratio of testosterone per Leydig cell was higher in cryptorchid animals than in controls, suggesting that, despite their reduction in number and the decrease of LH receptors, the Leydig cells of cryptorchid rams have an enhanced steroidogenic capacity. This study also confirms the important dysfunction of the Sertoli cells in cryptorchid rams.

Animals↗
PubMed1982

Effects of induced hypoprolactinaemia in the ram: plasma gonadotrophin levels, LH and FSH receptors and histology of the testis.

In order to investigate the effects of induced hypoprolactinaemia on gonadotrophin levels and testicular function in the ram, CB 154 was administered either in summer under natural photoperiod or in winter combined with a light regime stimulating prolactin release. Under natural photoperiod in summer, plasma FSH levels increased from 2.5 to 4 ng/ml in controls and from 2.5 to 8 ng/ml in CB 154-treated rams. Control and treated groups differed significantly (P less than 0.05) from the second week of treatment onwards. In the animals photostimulated in winter, treatment with CB 154 did not change plasma FSH levels; no effect of CB 154 on plasma LH levels was detected in either experiment. Treatment with CB 154 in summer led to an increase in the volumes of peritubular blood vessels and interstitial tissue. The number of Leydig cells per testis was significantly (P less than 0.05) increased in CB 154-treated rams. However, at the time of measurement, there was no change in the structure of the seminiferous tubules or in the production of germ cells. In winter in photostimulated animals, no effect of treatment with CB 154 was detected either on the structure of intestitial and tubular compartments or on spermatogenesis. The change in prolactin levels affected neither the number of LH receptors, expressed per Leydig cell, nor the number of FSH receptors, expressed per Sertoli cell, in the experiments. It is concluded that induced hypoprolactinaemia can modify the release of FSH in the ram and change the structure of the intertubular tissue but that it does not affect the number of LH and FSH receptors or impair spermatogenesis.

Animals↗
PubMedDate not supplied

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. Neither Sertoli cell number, Sertoli cell nuclear volume nor testicular FSH receptor number were affected by E2 immunization, but testis weight, Sertoli cell nuclear area, FSH receptor number and LH receptor number were significantly greater in autumn than in spring. A positive effect of E2 immunization on testicular LH receptors was evident in spring but not in autumn. Testicular androgen receptors were suppressed by E2 immunization but were not affected by season. It was concluded that E2 immunization results in moderate stimulation of the ovine testis to increase testosterone secretion and to enhance total daily spermatid production. This effect appears to result from a change in E2 negative feedback and increased pituitary gonadotropin secretion.

Androgen-Binding Protein↗
PubMedDate not supplied

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. Moreover, only one third of the graft was occupied by testicular tissue, in which the relative proportions of intertubular tissue and sex cords were not altered when compared with those of normal foetal testes. The remainder of the graft was occupied by teratoma. The total number of Leydig (-80%) cells, Sertoli (-66%) cells, gonocytes (-90%) and the total length of sex cords (-63%) per grafted testis were always significantly reduced (P < 0.02), whereas the sex cords were significantly increased in diameter (+36%; P = 0.02) as compared to those of non-grafted 60-day-old foetuses. However, in seven out of the nine testes, type A spermatogonia were obtained and in two of the seven a few type B or leptotene primary spermatocytes could be observed. The grafting of foetal testis in an adult scrotum induces differentiation of gonocytes into spermatogonia, independently of proliferation of Sertoli and Leydig cells.

Animals↗
PubMedDate not supplied

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 = 0.05); but their testis masses of their total contents of somatic (Leydig or Sertoli) cells did not differ significantly whatever the fetal age. At 100 and 140 days of gestation, testis and body masses were significantly correlated without difference between BB and ++ genotypes. In conclusion, the presence or absence of homozygous gene FecBB does not induce significant differences in somatic or germ cell composition of the testis between 60 and 140 days of gestation.

Animals↗
PubMedDate not supplied

Birth of piglets after OPS vitrification and transfer of compacted morula stage embryos with intact zona pellucida.

In swine, five to six days post-insemination, morulae and blastocysts are collected together after uterine flushing. The purpose of this study was to vitrify zona pellucida-intact morulae with Open Pulled Straw (OPS) technology and obtain piglets after transfer. Morulae (200) were vitrified after a two-step equilibration in ethylene glycol, dimethyl sulfoxide and sucrose in Hepes-buffered TCM199 + 20% NBCS medium (TCM). 2-6 morulae were loaded into OPS and plunged into liquid nitrogen. At embryo warming, a three-step dilution with decreasing concentrations of sucrose was applied. In each of 10 recipients, 20 morulae were transferred surgically. Day 25, gestation rate and the farrowing rate were 80% and 70%, respectively. The pregnant recipients farrowed from 1 to 8 piglets and the survival of total transferred embryos was 13%. Although survival rates are still compromised, OPS technology is therefore appropriate to cryopreserve porcine morulae with intact zona pellucida.

Animals↗
PubMedDate not supplied

Effects of supplementation with impuberal or adult testicular protein extracts on genital tract and testicular histology as well as hormonal levels in adult busulfan treated rats.

24 adult Wistar rats received one SC injection of busulfan (10 mg/kg BW) on day 0. They were injected daily from day 1 to day 10 either with BSA (1 and 2 mg/rat, n = 5 respectively), with acetonic extract of adult ram testicular cytosol (2 mg/rat, n = 10) or with acetonic extract of impuberal calf testicular cytosol (2 mg/rat, n = 4). 10 animals served as control. Animals were killed on day 17. Busulfan treatment induced decrease of total volumes of intertubular tissue and of Leydig cells per testis, of accessory glands, and of germ cells from type A spermatogonia to zygotene spermatocytes. Supplementation with adult testicular extract did not modify accessory glands but increased Leydig cell total volume, individual cellular and nuclear areas and Sertoli cell nuclear areas. It decreased further the germ cells from A spermatogonia to zygotene primary spermatocytes. Supplementation with impuberal testicular extract did not modify accessory glands, Leydig cell total volume, individual cellular and nuclear areas or Sertoli cell nuclear area. It increased the germ cells from A spermatogonia to zygotene primary spermatocytes to values intermediate between those of control and busulfan treated rats.

Animals↗
PubMedDate not supplied

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. Serum concentrations of FSH, LH and testosterone were compared at 20, 40 and 110 days of age. Histological analyses of Sertoli and germ cells in the seminiferous tubules and of Leydig cells in the intertubular tissue were performed before puberty and at adulthood. Testosterone serum concentrations were depleted in both models starting at 40 days of age and more in busulfan-treated rats. Both FSH and LH levels were increased from 20 days onwards in experimental rats. Additional cryptorchidism in busulfan-treated rats depressed the serum testosterone concentration. At 17 days of age, the cryptorchidism do not modify somatic or germ cell populations while busulfan treatment has induced a decrease of both these populations. Conversely, the cross sectional area of the somatic testicular cells was not affected whatever the treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMedDate not supplied

Effects of experimental cryptorchidism and subsequent orchidopexy on seminiferous tubule functions in the lamb.

The reversibility of damage caused by cryptorchidism to the seminiferous tubules of the lamb was investigated at various ages. Lambs were made bilaterally cryptorchid either at birth or at 2 months of age. Then orchidopexy was performed at either 2 or 4 months of age. In permanently cryptorchid lambs, spermatogenesis stopped completely, and Sertoli cell function, as measured by FSH receptors, androgen receptors and ABP, was much reduced (-96%, -86% and -81%, respectively). Orchidopexy allowed the cryptorchid seminiferous epithelium to grow again, but the more differentiated the germ cells, the less they were capable of restoration. Even in 0- to 2- and 0- to 4-month-old temporarily cryptorchid lambs that had recovered normal Sertoli cell function, 16 to 49% of the tubules still were empty. It was concluded that cryptorchidism irreversibly damages the seminiferous tubules at a level other than the hormone receptors.

Age Factors↗