Browsing by Author "ROBLERO, L"
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- ItemEFFECT OF EXOGENOUS SEX STEROIDS UPON THE NUMBER OF GERM-CELLS AND THE GROWTH OF FETAL OVARIES GRAFTED UNDER THE KIDNEY CAPSULE OF ADULT OVARIECTOMIZED HAMSTERS(1983) ARRAU, J; ROBLERO, L; CURY, M; GONZALEZ, REffect of estradiol (E), progesterone (P) and testosterone propionate (T) upon growth and germ cell population of fetal ovaries transplanted under the kidney capsule of adult ovariectomized hamsters was examined. Fetal ovaries were obtained 15 days postcoitum and the host received daily s.c. injections of E (1 .mu.g/day), P (5 mg/day), T (500 .mu.g/day) or E + P in 0.1 ml oil for 25 days beginning 5 days before grafting. One day after the last injection, the size of the ovary, the germ cell population and plasma steroid levels were assessed. Results of hormone assays indicate that daily steroid administration was able to maintain continuously elevated plasma levels of the corresponding hormone. Interconversions or steroid secretion by the graft, if any, were not reflected in the peripheral circulation. Growth of the graft was stimulated by T and inhibited by P, in comparison with E and oil-treated controls. All germ cells were at the stage of primary-oocyte-forming part of a primordial or growing follicle. Their absolute number was significantly increased by T and E and significantly decreased by P and E + P. The number of oocytes per mm3 of ovary was increased 80, 48 and 40% with E, T and E + P, respectively. In the hamster, exogenous sex steroids given to the host can exert specific effects upon the growth and oocyte population of a grafted fetal ovary. Whether or not the action of steroids upon the graft is a direct one and whether they influenced oogonial mitosis, the evolution of the meiotic prophase or atresia of primary oocytes remains to be determined.
- ItemHIGH POTASSIUM CONCENTRATION IMPROVES THE RATE OF ACROSOME REACTION IN HUMAN-SPERMATOZOA(1988) ROBLERO, L; FERNANDEZ, E; GUADARRAMA, A; ZEGERSHOCHSCHILD, F; ORTIZ, MEProgressively motile spermatozoa recovered by swim-up method from semen of two fertile men were inoculated for 24 hours in culture media containing either 4.7, 15, or 25 mM of potassium (K). Aliquots of each culture condition were obtained at 0, 1, 5, 10, and 24 hours of incubation for the assessment of progressive motility, percentage of dead spermatozoa, and percentage of acrosome reaction (AR), as measured by triple-stain technique. A total of ten experiments including each K concentration were analyzed. The results of this study showed no effect of K concentration on the percentage of progressively motile spermatozoa, irrespective of the time of incubation. The percentage of live spermatozoa was significantly greater in culture medium containing 25 mM K (P < 0.05). There was a greater percentage of reacted spermatozoa with 25 mM K, as compared with 4.7 and 15 mM (P < 0.05). Furthermore, the time taken to acheive 20% of AR was 2 hours at 25 mM K compared with 10.9 hours at 4.7 mM K.
- ItemMETHOD FOR THE INVIVO EXPERIMENTAL-STUDY OF MEIOTIC PROPHASE IN THE GOLDEN-HAMSTER (MESOCRICETUS-AURATUS)(1979) ARRAU, J; ROBLERO, L
- ItemNEW OBSERVATIONS ON THE ONSET AND DURATION OF THE MEIOTIC PROPHASE IN THE FEMALE GOLDEN-HAMSTER (MESOCRICETUS-AURATUS)(1981) ARRAU, J; ROBLERO, L; CURY, M