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or lhrh in perifused pituitary glands from neonatally estrogenized female rats
-84 LH AND FSH SECRETION IN CHRONICALLY RESTRAINED MALE RATS. ROLE OF THE TESTIS. Arianavarreta, C; Calder6n, M.D; Velasco, C; L6pez-Calder6n,A. Dept. of Physiology. Faculty of Medicine. Complutensis University. 28040 Madrid. SPAIN. Chronic stress inhibits testicular and gonadotropin secretion. The aim of this work was to study gonadotropin secretion during chronic stress in intact or orchidectomizedrats. Adult male Wistar rats were orchidectomizedor SHAM operated. Ten days after surgery half of each group of animals were restrained six hours daily (from 10 a.m. to 4 p.m.) during four days, and the rest remained undisturbed to serve as controls. After the last stress period all groups were decapitated. Plasma corticosterone,LH and FSH as well as pituitary gonadotropin content were determined. In intact animals chronic stress reduced plasma LH (from 38.3 + 1.5 in control rats to 23.8 + 1.8 ng/ml, mean + s.e.m., ~(0.01) and plasma FSH (from 254 + 15 70 164 + 12 ng/ml, p(O.017, whereas their pituitary contents were not modified. In gonadectomizedFats submitted to chronic stress, LH and FSH pituitary contents remained unchanged. Plasma LH levels were reduced as compared to controls but no plasma FSH modification could be observed.Castration increased plasma corticosterone levels in unrestrained rats from 14.5 + 2.3 to 22.4 + 2pg/dl, but corticosterone responses to stress were similar in intact or orchiiectomizedrats. These results suggest that: 1) Chronic stress inhibits pituitary LH and FSH release in intact animals; 2) FSH decrease after stress seems to be testicular dependent. This work was in part supported by Grant n Q 0371/8d from CAICYT. NIADDK provided the RIA reagents used for measurements ofrat LH and FSM.
85 mOLACTINRL)iESPONSE TO ESTRADIOL AND/OR LHRH IN PERIFUSED PITUITARY GLANDS FROM NEONATALLY ESTROGENIZED FEMALE RATS; Fernandes-Galas,C; Rodriguez, P; Vaticdn, M.D; Tejero, A. Dept. of Physiology; Faculty of Medicine: Complutense University; 28040 Madrid; SPAIN. Adult ovariectomized female rats neonatally treated with estradiol benzoate (E) exhibit a greater PRL response to estrogen stimulation than control rats CC), whereas the administration of LHRH to E produces a decrease in PRL levels, unobserved in the C group (*). To study if those presumptive actions are exerted at the pituitary level and the possible interrelationbetween both stimuli a perifusion system was used. The pituitaries were superfusad with the buffer, either alone or containing estradiol 10m7 M over a period of 200 min. Both at 112 and 144 min twc 4-min stimuli of LHRH (2ng/ml) or medium only were pumped through the perifusion chambers. Results show: a) estradiol prevented the decline of basal PRL secretion (~(0.01) bo,thin E and C groups, b) LHRH fails to alter PRL secretion at a dose and exposure time that is effective on LH release (LH increments over basal values amounting no less than 280 %) and c) treatment of pituitaries with both estradiol and LHRH do not modify the above secretion patterns of both hormones. Although only estrogens have been shown to affect PRL secretion directly at the level of pituitary no differences were found between C and E animals, thus other experimental approaches must be sought to explain the different effects obtained "in viva" for both stimuli upon the estrogenized female rat. (*) Vatic6n M.D., Aguilar E., FernBndez-GalazC., Tejero A.- Rev. Esp. Fisiol. 36: 371-376, 1980 Supported by CAICYT Grant nQ 0641/81. The NIADDK provided the RIA reagents used for measurements of rat LH and PRL.
86 EFFECT OF ESTROGEN AND PROGESTOGEN PRIMING UPON LH AMD FSH SECBBTION IN GnBB STIMULATED MALE RAT PITUITARY CELL CULTDBE. Mendoza, M.E.*j Ranano, M.; Menjivar, M. and Garza-Flores, J. Depto. de Fisiologia. Centro de Investigacign y de Estudios Avanzadoe de1 IPN. Apdo. Postal 14-740, Mgxico, D.F. 07000 y Departamento de Biologfa de la Reproduccidn de1 Instituto National de la Nutrici& Salvador Zubirgn, Mexico, D.F. 14000. The modulatory effect of estrogens and progestogens upon the hypotalamic-pituitaryunithas baen extensively studied in the female rat. liowever, not much information is available regarding the influences of these steroid hormones on the pituitary of the male rat, particularly in the primary cell culture. We have investigated the effects of178 estradiol (E2), progesterone(P)and the synthetic progestogen noretinisterone(NET) on the basal and GnRH stimulated gonadotrophin secretion by the cultured pituitary cells obtained from adult male rats. The cells were maintained,during 48 hs in a medium containing Dulbecco MBM plus 15% fetal bovine serum. After 49 hs of culture, the pituitary cells were incubated for 4 hs in Dulbecco MBM in the presence or absence of the different steroids. (E2 10.6, P 47.7 and NET 44.8 Ml). At the end of this period the medium was replaced by Dulbecco MBM with or without GnRB (2.0~10'~#)'and the cells were incubated for 2 additional hs. LB and FSH were determined in the medium by specific radioinununoassays. The results disclosed that the baseline LH secretion was not modified by the E2, P, or NET priming. However the simultaneous addition of E2 and P increased by 100% the stimulated LH secretion. This effect was not observed when E2 and NET were added together. The basal and stimulated FSH secretion were increased by E2 or NET priming but not with P. When E2 WAS used simultaneously with NET or P the effect of GnPB was significantly increased (p
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85 mOLACTINRL)iESPONSE TO ESTRADIOL AND/OR LHRH IN PERIFUSED PITUITARY GLANDS FROM NEONATALLY ESTROGENIZED FEMALE RATS; Fernandes-Galas,C; Rodriguez, P; Vaticdn, M.D; Tejero, A. Dept. of Physiology; Faculty of Medicine: Complutense University; 28040 Madrid; SPAIN. Adult ovariectomized female rats neonatally treated with estradiol benzoate (E) exhibit a greater PRL response to estrogen stimulation than control rats CC), whereas the administration of LHRH to E produces a decrease in PRL levels, unobserved in the C group (*). To study if those presumptive actions are exerted at the pituitary level and the possible interrelationbetween both stimuli a perifusion system was used. The pituitaries were superfusad with the buffer, either alone or containing estradiol 10m7 M over a period of 200 min. Both at 112 and 144 min twc 4-min stimuli of LHRH (2ng/ml) or medium only were pumped through the perifusion chambers. Results show: a) estradiol prevented the decline of basal PRL secretion (~(0.01) bo,thin E and C groups, b) LHRH fails to alter PRL secretion at a dose and exposure time that is effective on LH release (LH increments over basal values amounting no less than 280 %) and c) treatment of pituitaries with both estradiol and LHRH do not modify the above secretion patterns of both hormones. Although only estrogens have been shown to affect PRL secretion directly at the level of pituitary no differences were found between C and E animals, thus other experimental approaches must be sought to explain the different effects obtained "in viva" for both stimuli upon the estrogenized female rat. (*) Vatic6n M.D., Aguilar E., FernBndez-GalazC., Tejero A.- Rev. Esp. Fisiol. 36: 371-376, 1980 Supported by CAICYT Grant nQ 0641/81. The NIADDK provided the RIA reagents used for measurements of rat LH and PRL.
86 EFFECT OF ESTROGEN AND PROGESTOGEN PRIMING UPON LH AMD FSH SECBBTION IN GnBB STIMULATED MALE RAT PITUITARY CELL CULTDBE. Mendoza, M.E.*j Ranano, M.; Menjivar, M. and Garza-Flores, J. Depto. de Fisiologia. Centro de Investigacign y de Estudios Avanzadoe de1 IPN. Apdo. Postal 14-740, Mgxico, D.F. 07000 y Departamento de Biologfa de la Reproduccidn de1 Instituto National de la Nutrici& Salvador Zubirgn, Mexico, D.F. 14000. The modulatory effect of estrogens and progestogens upon the hypotalamic-pituitaryunithas baen extensively studied in the female rat. liowever, not much information is available regarding the influences of these steroid hormones on the pituitary of the male rat, particularly in the primary cell culture. We have investigated the effects of178 estradiol (E2), progesterone(P)and the synthetic progestogen noretinisterone(NET) on the basal and GnRH stimulated gonadotrophin secretion by the cultured pituitary cells obtained from adult male rats. The cells were maintained,during 48 hs in a medium containing Dulbecco MBM plus 15% fetal bovine serum. After 49 hs of culture, the pituitary cells were incubated for 4 hs in Dulbecco MBM in the presence or absence of the different steroids. (E2 10.6, P 47.7 and NET 44.8 Ml). At the end of this period the medium was replaced by Dulbecco MBM with or without GnRB (2.0~10'~#)'and the cells were incubated for 2 additional hs. LB and FSH were determined in the medium by specific radioinununoassays. The results disclosed that the baseline LH secretion was not modified by the E2, P, or NET priming. However the simultaneous addition of E2 and P increased by 100% the stimulated LH secretion. This effect was not observed when E2 and NET were added together. The basal and stimulated FSH secretion were increased by E2 or NET priming but not with P. When E2 WAS used simultaneously with NET or P the effect of GnPB was significantly increased (p
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