The effect of serum on in vitro maturation, in vitro fertilization and steroidogenesis of bovine oocytes co-cultured with granulosa cells

The influence of fetal calf serum alone (fcs) or associated with proestrous (FCS + PCS), ESTROUS (FCS + ECS) or metaestrous (FCS + MCS) cow serum added to the culture medium and of the steroids produced by co-cultured granulosa cells were evaluated in terms of the in vitro maturation (IVM) and fertilization (IVF) of bovine oocytes. Supplementation of the medium with 9FCS + ECS and FCS + MCS resulted in higher proportions of oocytes that reached metaphase II (96.0 per cent and 93.3 per cent, respectively) and in higher proportion of embryos that reached the four- and eight-cell/morula stages (51.9 per cent and 65.6 per cent, respectively), whereas the supplementation with FCS and FCS + pcs resulted in only 79.2 per cent and 67.5 per cent, respectively, of matured oocytes nd 26.7 per cent and 34.4 per cent, respectively, of cleaved embryos. These findings show that the best IVM and IVF were obtained at lower concentrations of estradiol produced by co-cultured granulosa cells (supplementation with FCS + ECS: 10.3 ng/ml and FCS + MCS: 2.1 ng/ml), whereas the worst results in IVM and IVF occurred at higher concentrations of estradiol that were obtained with FCS (33.1 ng/ml) and FCS + PCS (19.9 ng/ml) supplementation. These data suggest an inhibitory effect of estradiol on resumption of oocyte meiosis in vitro

Effect of an LH-RH analog on cat testis and adrenal cortex function

The LH-RH analog-LH-RH-A (des-Gly10, [D-Trp6]-LH-RH ethylamide) was administerd in pharmacological doses (20 µg/Kg, sc) to adult male cats for 15 days and its effect on testis and adrenal function was determined. Dayly adminitration of the analog promoted a 3-fold increase in plasma testosterone levels after 7 days, indicating stimulatory effect of LH-RH-A (mean ñ SD for 6 treated cats, 1.88 ñ 0.35 vs 0.51 ñ 0.08ng/ml for 6 control cats). After 15 days the LH-RH-A-treated group exhibited a similar plasma testosterone concentration as the control group (mean ñ SD, 0.96 ñ 0.35 ng/ml vs 0.88 ñ 0.39 ng/ml, respectively), similar testicular and adrenal weights and no significant differences in the spermatogenic process. However, semiquantitative analysis of the zona fasciculata of the adrenals from the LH-RH-A treated group showed a significant accumulation of a substance not stained by hematoxylin-eosin or Schiff periodic acid (mean ñ SD of index of accumulation was 3.50 ñ 0.4 for treated cats vs 2.20 ñ 0.3 for control cats). The present results show that pharmacological doses of LH-RH-A have an effect on the adrenal cortex of cats without modifying spermatogenesis or plasma testosterone levels

The effects of guanethidine induce denervation of the peripheral sympathetic nervous system on the onset of puberty in female rats

Intraperitoneal injection of guanethidine (50 mg Kg-1 day-1) in newborn rats produeces complete and permanent sympathectomy. The present study was performed to evaluate the effect of this form of denervation on the onset of puberty in female rats. Treatment began 7 days after birth and was maiantained for 3 weeks. In the 45th day, animals were killed by decaptation and plasma LH and FSH levels wee measured. Based on the day of vaginal opening (puberty index), the results show that guanethidine induces a delay in the onset of puberty. The concentrations of LH and FSH in the plasma were not statistically different from those in control rats

Histochemical and histological analysis of the leydig cells of cats treated with a supraphysiological dose of LH-RH analog

An LH-RH analog (des-Gly10, [D-Trp6]-LH-RH A) was administered to adult male cats for 67 days (20 microng/Kg,sc) in order to study its inhibitory effects on the structure of Leydig cells, as deter,mined by histological and histochemical-morphometric techniques. Histological examination showed that LH-RH A promotes a decrease in the volume of the interstitial tissue. In addition, Leydig cell nuclei exhibited marked structural alterations. Morphometric analyses utilizing histochemistry of the enzyme 3-ß-hydroxysteroid dehydrogenase (3-ß-HOST-D) as a marker of Leydig cells also demostrated a signifcant decrease of the relative volume occupied by the Leydig cells isn the testis