1,721,051 research outputs found
In vitro nitric oxide effects on basal and gonadotropin-releasing hormone-induced gonadotropin secretion by pituitary gland of male crested newt (Triturus carnifex) during the annual reproductive cycle
No full textThe objective of this study was to test the possible nitric oxide (NO) involvement in pituitary gonadotropin secretion in the male crested newt, Triturus carnifex. Pituitaries were incubated in vitro with medium alone, GnRH, NO donor (NOd, sodium nitroprusside), NO synthase inhibitor (NOSi, Nomega-nitro-L-arginine methyl ester), cGMP analogue (cGMPa, 8-bromo-cGMP), soluble guanylate cyclase inhibitor (sGCi, cystamine), GnRH plus NOSi, GnRH plus sGCi, and NOd plus sGCi during the annual reproductive cycle: pre-reproduction, reproduction (noncourtship and courtship), and the refractory, recovery, and estivation periods. To determine pituitary gonadotropin secretion indirectly, newt testes were superfused in vitro with preincubated pituitaries, and androgen release was determined. NO synthase (NOS) activity and cGMP levels were assessed in the preincubated pituitaries. Medium alone- and GnRH-preincubated pituitary increased androgen secretion during pre-reproduction, noncourtship, courtship, and recovery; the GnRH-induced increase was higher than the medium alone-induced increase during pre-reproduction, noncourtship, and recovery. NOd and cGMPa increased androgens in all reproductive phases considered except courtship; the NOd- and cGMP-induced increase was higher than the medium alone-induced increase during pre-reproduction, noncourtship, and recovery. NOS activity was highest during courtship and lowest during the refractory and estivation periods. GnRH increased NOS activity during pre-reproduction, noncourtship, and recovery. Cyclic GMP levels were highest during courtship and lowest during the refractory period and estivation. GnRH increased cGMP levels during pre-reproduction, noncourtship, and recovery, while NOd did so during all reproductive phases considered. These results suggest that basal and GnRH-induced gonadotropin secretion are up-regulated by NO in the pituitary gland of the male Triturus carnifex
Corrigendum to “Presence and function of kisspeptin/KISS1R system in swine ovarian follicles” (Theriogenology (2018) 115 (1–8), (S0093691X1830147X), (10.1016/j.theriogenology.2018.04.006))
No full textThe authors regret the following changes to the author group G. Basinia, F. Grassellia, S. Bussolatia, R. Ciccimarraa, M. Maranesib, A. Bufalarib, C. Dall'Agliob, F. Parilloc,#, M. Zeranib,c,*. a Dipartimento di Scienze Mediche Veterinarie, Università di Parma, 43126 Parma, Italy. b Dipartimento di Medicina Veterinaria, Università di Perugia, 06126 Perugia Italy. c Scuola di Bioscienze e Medicina Veterinaria, Università di Camerino, 62024 Matelica Italy. # Deceased. * Corresponding author: tel.: +39 0755857642; fax +39 0755857654. E-mail address: [email protected] (M. Zerani). And to the acknowledgements and figures
PGE2-ALPHA, PGE2, PROGESTERONE, AND ESTRADIOL-17-BETA, SECRETION BY THE CORPUS-LUTEUM OF THE OVIPAROUS LIZARD, PODARCIS-SICULA-SICULA - INVITRO STUDIES
No full textThe release in vitro of prostaglandin F2alpha (PGF2alpha), prostaglandin E2 (PGE2), progesterone, androgens and estradiol-17beta by the corpora lutea (CL) of the oviparous lizard, Podarcis s. sicula, was studied. In addition, the in vitro effects of PGF2alpha and PGE2 on sex steroid release by CL were evaluated. Corpora lutea were divided into four types, according to their different developmental stage: CL1 (unshelled eggs in the oviduct); CL2 (shelled eggs in the oviduct); CL3 (eggs laid 6 h previously); CL4 (eggs laid 48 h previously) and were placed into culture. PGF2alpha secretion was highest in CL4 incubated samples and lowest in CL2 and PGE2 was highest in CL1 and CL2. Progesterone secretion was highest in CL2 and lowest in CL4; androgens were not detectable and estradiol-17beta secretion was highest in CL2. PGF2alpha decreased progesterone secreted by CL1, CL2 and CL3, while it did not modify release of androgens and estradiol-17beta. PGE2 did not affect sex steroid release. These data suggest a role of PGF2alpha in inducing luteolysis, while PGE2 could be implied in the maintenance of CL. A role of progesterone during gestation of Podarcis s. sicula was also confirmed
PROSTAGLANDINS AND SEX STEROIDS FROM REPTILIAN (PODARCIS-SICULA-SICULA) OVARIAN FOLLICLES AT DIFFERENT DEVELOPMENTAL STAGES
No full textProstaglandin F2alpha (PGF2alpha), prostaglandin E2 (PGE2), progesterone, androgens, and estradiol-17beta in vitro basal release by follicles of the oviparous lizard, Podarcis s. sicula was studied; in addition, the in vitro effect of PGF2alpha and PGE2 on sex steroid release was evaluated. Follicles were divided according to the different vitellogenic developmental stages: pre-vitellogenic, early-vitellogenic, mid-vitellogenic and fully-grown. PGF2alpha and progesterone basal release was highest in fully-grown follicles; PGE2 and estradiol basal release was highest in early-vitellogenic follicles; androgens basal release was detectable in mid-vitellogenic and fully-grown vitellogenic follicles only. PGF2alpha increased progesterone release by fully-grown follicles; PGE2 increased estradiol release by all follicle types, except by early-vitellogenic ones. The present data suggest that PGF2alpha and PGE2 exert different roles on follicles: PGF2alpha seems to induce ovulation through the mediation of progesterone, while PGE2 seems to be implied in the start and the sustaining of oocyte vitellogenic development through the mediation of estradiol
Effects of aglepristone administration during the luteal phase of progesterone and LH concentrations of non pregnant bitches
No full textProstaglandin F2a in female water frog Rana esculenta: Plasma levels during the annual cycle and effects of exogenous PGF2a on circulating sex hormones.
No full textImmunopresence and enzymatic activity of nitric oxide synthases, cyclooxygenases and PGE2-9-ketoreductase and in vitro production of PGF2α, PGE2 and testosterone in the testis of adult and prepubertal alpaca (Lama pacos).
No full textThis study presents the first evidence for differences in COXs, PGE2-9-ketoreductase and NOSs immunopresence
and enzyme activity, and prostaglandin and testosterone production between the testes of adult
and prepubertal alpacas. The prepubertal testis immunohistochemical data revealed that COX1 was
expressed in spermatogonia and endothelial cells whereas COX2 was present only in the stromal cells.
In adult animals, COX2 immunosignals were evidenced in germ cells, as well as both COX1 and -2 in
Leydig and Sertoli cells. In adult testes, the spermatogonia, spermatocytes and round spermatids had
expression of e- and n-NOS only, whereas elongated spermatids exhibited immunopositivity for i- and
e-NOS and Sertoli cells expressed only n-NOS. In prepubertal alpacas, i-NOS was localized in spermatogonia,
e-NOS in Sertoli cells and all three NOS isoforms in Leydig cells. PGE2-9-ketoreductase immunopresence
was observed in spermatogonia nuclei and cytoplasm of prepubertal testis whereas they
were localized in spermatid acrosomal vesicle of adult. The enzymatic data indicated that COX1 activity
was higher than COX2 in adult alpaca testis whereas the activity of COX2 was greater than that of COX1
in prepubertal animals. Total NOS and PGE2-9-ketoreductase activities were more extensive in adult
alpacas. In vitro hormone production results showed that prepubertal testes released lower amounts of
testosterone and PGF2a while PGE2 synthesis was six times more elevated than in in vitro incubated
adult testes. Taken together, the data on COX2, i-NOS and PGE2 led us to hypothesize that development
in prepubertal male reproductive tissues utilizes a mechanism similar to that of inflammation
RELATIONSHIPS AMONG GNRH, SUBSTANCE-P, PROSTAGLANDINS, SEX STEROIDS AND AROMATASE-ACTIVITY IN THE BRAIN OF THE MALE LIZARD PODARCIS-SICULA-SICULA DURING REPRODUCTION
No full textThe release of PGF(2 alpha) and PGE(2), progesterone, androgens and oestradiol in vitro, and the aromatase activity in the brain of the male lizard Podarcis sicula sicula during three different phases of the reproductive period were evaluated. In addition, the effects of salmon GnRH, substance P, salmon GnRH antagonist, substance P antagonist, PGF(2 alpha), PGE(2) and acetylsalicylic acid on the release of prostaglandins and sex steroids and on aromatase activity in the brain were evaluated during the same three phases. PGF(2 alpha), oestradiol and aromatase activity were higher during the refractory phase, androgens during the fighting phase, and progesterone during the mating phase, while PGE, was lower during the refractory phase. Treatment with salmon GnRH increased PGF(2 alpha), oestradiol and aromatase activity, but decreased the amount of androgens released. Substance P decreased PGF(2 alpha), oestradiol and aromatase activity, but increased the amount of androgens released. PGF(2 alpha), increased oestradiol and aromatase activity, but decreased the amount of androgens released. Acetylsalicylic acid decreased PGF(2 alpha), oestradiol and aromatase activity, but increased the amount of androgens released. These data suggest that salmon GnRH and substance P have different roles in reproductive processes, with opposite mechanisms, in the central nervous system of this male lizard: salmon GnRH seems to be involved in regulating the refractory phase, while substance P plays a role in regulating the fighting phase
Nitric oxide synthase acutely regulates progesterone production by in vitro cultured rabbit corpora lutea
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