Effect of progesterone and estradiol-17β on ovarian fluid secretion in the threespine stickleback, Gasterosteus aculeatus L., form trachurus

1979 ◽  
Vol 57 (2) ◽  
pp. 468-471 ◽  
Author(s):  
T. J. Lam ◽  
K. Chan ◽  
W. S. Hoar
Keyword(s):  
Gasterosteus Aculeatus ◽  
Fluid Secretion ◽  
Threespine Stickleback ◽  
Corpora Lutea ◽  
Fluid Accumulation ◽  
Ovarian Fluid ◽  
Estradiol 17Β ◽  
Ovarian Cavity ◽  
Stimulation Of

Immersion of postspawning sticklebacks in seawater containing 0.5 ppm progesterone for 5 days (medium changed daily) caused marked fluid accumulation in the ovarian cavity. A similar effect was obtained in overripe fish treated in the same way for 9 days; overripe fish have overripe ovulated eggs in the ovarian cavity with very little fluid. Estradiol-17β (1 ppm) also caused ovarian fluid secretion in some postspawning fish, but this may be related to its marked stimulation of ovarian recrudescence. The findings are discussed in relation to the possible role of the postovulatory corpora lutea in ovarian fluid secretion for the maintenance of ovulated eggs.

Flexibility of nuptial colouration in a unique ecotype of Threespine Stickleback (Gasterosteus aculeatus)

2021 ◽  
Author(s):  
Rachel Corney ◽  
Anne Haley ◽  
Laura Weir
Keyword(s):  
Breeding Season ◽  
Gasterosteus Aculeatus ◽  
Colour Change ◽  
Threespine Stickleback ◽  
Relative Role ◽  
Mate Quality ◽  
Breeding Seasons ◽  
Potential Signal ◽  
Intersexual Competition

Nuptial colouration in animals may serve as a signal of competitor and/or mate quality during breeding. In many temperate fishes, nuptial colouration develops during discrete breeding seasons and is a target of sexual selection. We examine nuptial colouration and behaviour of a unique ecotype of Threespine Stickleback (Gasterosteus aculeatus Linnaeus, 1758), wherein males turn from dull brown-grey to pearlescent white during the breeding season. The main goal of this work was to determine the relative role of white colouration in intersexual competition and mate choice. In a combination of a field and laboratory work, we found that males are brightest white when engaging in courtship activities in the presence of a female; this indicates that white colouration may be primarily related to enhancing signalling during mate attraction. White colouration intensity increased as the breeding season progressed and may be related to an influx of conspecifics. Colour change from cryptic grey to bright white occurred rapidly (< 90 seconds) and may be deployed to enhance behavioural signals. We conclude that bright white colouration in the white ecotype is a potential signal of mate quality and may have evolved from a previously existing capacity for colour plasticity in common Threespine Stickleback.

scholarly journals Role of Cyclooxygenase Enzymes in a Murine Model of Experimental Cholera

2003 ◽  
Vol 71 (11) ◽  
pp. 6234-6242 ◽  
Author(s):  
Deborah L. Gessell-Lee ◽  
Vsevolod L. Popov ◽  
Istvan Boldogh ◽  
Juan P. Olano ◽  
Johnny W. Peterson
Keyword(s):  
Oxidative Stress ◽  
Tissue Injury ◽  
Fluid Secretion ◽  
Fluid Accumulation ◽  
Acid Metabolites ◽  
Cox 2 ◽  
Small Intestinal ◽  
Cox 1 ◽  
Experimental Cholera

ABSTRACT Nonsteroidal anti-inflammatory drugs (e.g., indomethacin) inhibit and reduce the fluid secretion responses elicited by cholera toxin (CT), but it has not been conclusively determined which cyclooxygenase (COX) isoform is involved in CT's action. This study evaluated the role of the COX enzymes and their arachidonic acid metabolites in experimental cholera. Swiss-Webster mice were dosed with celecoxib and rofecoxib and challenged with CT in ligated small intestinal loops, and intestinal segments from mice deficient in COX-1 and COX-2 were challenged with CT. The effects of CT on fluid accumulation, prostaglandin E2 production, mucosal tissue injury, and markers of oxidative stress were measured. Celecoxib and rofecoxib given at 160 μg per mouse inhibited CT-induced fluid accumulation by 48% and 31%, respectively, but there was no significant difference among cox-1−/− and cox-2−/− mice in response to CT compared to wild-type controls. CT elevated tissue levels of oxidized glutathione and lipid peroxides and elicited small intestinal tissue injury in two of five cox-1−/− and four of five cox-2−/− mice. A role for COX-2 in CT's mechanism of action has previously been suggested by the effectiveness of COX-2 inhibitors in reducing CT-induced fluid secretion, but CT challenge of COX-1 and COX-2 knockout mice did not corroborate the pharmacological data. The results of this study show that CT induced oxidative stress in COX-deficient mice and suggest a tissue-protective role for arachidonic acid metabolites in the small intestine against oxidative stress.

SOME EFFECTS OF GONADOTROPIC HORMONES ON THE THREESPINE STICKLEBACK, GASTEROSTEUS ACULEATUS

1963 ◽  
Vol 41 (6) ◽  
pp. 1045-1053 ◽  
Author(s):  
S. Nazar Ahsan ◽  
William S. Hoar
Keyword(s):  
Gasterosteus Aculeatus ◽  
Late Summer ◽  
Reproductive Organs ◽  
Threespine Stickleback ◽  
Late Winter ◽  
Condition Characteristic ◽  
Mature Fish ◽  
Sexually Mature ◽  
Gonadotropic Hormones ◽  
Stimulation Of

Sticklebacks collected during the autumn and maintained under 8-hour daily photoperiods did not mature sexually; their gonads remained in the condition characteristic of late summer and autumn fish in nature and probably did not change after the fish were placed under controlled photoperiods. No stimulation of the gametogenetic and related tissues occurred when these fish were treated with purified mammalian FSH (Armour) but LH (Armour) produced a maturation of all gonads to stages characteristic of late winter and spring fish; with LH, 80% of the individuals attained the stages of sexually mature fish in nature. Chorionic gonadotropins (Organon) also had a stimulatory effect but were considerably less active than the LH; PMS was more effective than HCG. TSH (Parke Davis or Organon) had a marked gonadotropic action as well as the expected thyrotropic effect and stimulated the reproductive organs to about the same degree as the chorionic gonadotropins. Crude extracts of alcohol-preserved salmon pituitaries were only mildly active but stimulated all gonads to stages beyond those normally found in the late summer and autumn.

Phenotypic, genetic, and environmental integration of morphology in a stream population of the threespine stickleback, Gasterosteus aculeatus

1995 ◽  
Vol 52 (6) ◽  
pp. 1307-1317 ◽  
Author(s):  
Jeffrey V. Baumgartner
Keyword(s):  
Natural Selection ◽  
Gasterosteus Aculeatus ◽  
Genetic Factors ◽  
Threespine Stickleback ◽  
Morphometric Traits ◽  
Genetic Determination ◽  
Functional Phenotype ◽  
Pleiotropic Mutation

Phenotypic, genetic, and environmental variances and covariances for 33 morphometric traits were estimated for a population of threespine stickleback, Gasterosteus aculeatus, from the Brush Creek drainage, California, by sib analysis of laboratory-bred families. Heritabilities of the morphometric traits ranged from −0.28 to 0.78, and were moderately low (mean h2 = 0.26); the mean and range of heritabilities for five phenotypic eigenvectors were similar. The average coefficient of genetic determination of the traits and eigenvectors was high (0.57 and 0.63, respectively), indicating a substantial genotypic contribution to variation in body morphology. The defensive complex, a functional set of bony armor structures, was genetically and environmentally integrated: genetic factors (e.g., pleiotropy) are reinforced by environmental factors to produce a functional phenotype. Other components of morphology, including body form, were environmentally, but not genetically, integrated. Given the importance of genetic factors to evolutionary change under natural selection, these results implicate natural selection in the evolution of the defensive complex; the role of natural selection in the evolution of other components of morphology is equivocal. Genetic integration of functionally (phenotypically) independent traits suggests that stochastic processes or pleiotropic mutation also have played a role in the evolution of morphology in this population of sticklebacks.

Overripe eggs and postovulatory corpora lutea in the threespine stickleback, Gasterosteus aculeatus L., form trachurus

1978 ◽  
Vol 56 (9) ◽  
pp. 2029-2036 ◽  
Author(s):  
T. J. Lam ◽  
Y. Nagahama ◽  
K. Chan ◽  
W. S. Hoar
Keyword(s):  
Gasterosteus Aculeatus ◽  
Corpora Lutea ◽  
Animal Pole ◽  
Distended Abdomen ◽  
Threespine Sticklebacks ◽  
Active Condition ◽  
Percentage Water Content ◽  
Ovarian Cavity ◽  
Whole Ovaries ◽  
Bathing Fluid

Threespine sticklebacks (Gasterosteus aculeatus L., form trachurus) with overripe, ovulated eggs have a hard 'berried' abdomen, easily distinguishable from the soft, smoothly distended abdomen of fish with normal ovulated eggs. The 'berried' fish weigh less and have a smaller GSI than 'nonberried' ovulated fish but the percentage water of their whole ovaries is the same. In contrast with 'nonberried' fish, 'berried' fish do not respond to male courtship. Overripe eggs are typical of those in other species with aggregation of cytoplasm and oil droplets at the animal pole. However, in contrast with normal ovulated eggs, they are larger, more transparent, and have a higher percentage water content although surrounded by much less fluid within the ovarian cavity. Overripe eggs do not appear to form a perivitelline space in fresh water. In 'berried' fish both the postovulatory corpora lutea (follicles) and ovarian epithelium (lining of the ovarian cavity) show histological signs of regression, in contrast with the histologically active condition of these tissues in fish with normal ovulated eggs. It is suggested that postovulatory corpora lutea play a role in maintenance of ovulated eggs in the ovarian cavity through secretion of steroid(s) which in turn stimulate the ovarian epithelium to secrete the bathing fluid of the eggs.

ABSENCE OF COMPENSATORY OVARIAN HYPERTROPHY IN RATS WITH ANTERIOR HYPOTHALAMIC LESIONS

1961 ◽  
Vol 36 (2) ◽  
pp. 180-184 ◽  
Author(s):  
Béla Flerkó ◽  
Vera Bárdos
Keyword(s):  
Essential Role ◽  
Ovarian Tissue ◽  
Vaginal Smear ◽  
Corpora Lutea ◽  
Vaginal Smears ◽  
Hypothalamic Area ◽  
Unilateral Ovariectomy ◽  
Hypothalamic Lesions ◽  
Oestrogen Level ◽  
Stimulation Of

ABSTRACT Absence of compensatory ovarian hypertrophy in »constant oestrus rats« from lesions in the anterior hypothalamic area suggests that nervous elements localized in this region play an essential role in the stimulation of gonadotrophin output by diminution of the blood oestrogen level. The constant vaginal oestrus after unilateral ovariectomy in the majority of animals was, however, repeatedly interrupted by vaginal smears of a dioestrous type. The appearance of a dioestrous vaginal smear in the »hypothalamic constant oestrus rats« is often associated with some luteinisation. It is assumed that diminution of the blood oestrogen level by reduction of ovarian tissue in these animals may bring about a release of LH sufficient to cause formation of corpora lutea.

ZUR BEDEUTUNG DES HYPOPHYSÄREN LUTEINISIERUNGSHORMONS FÜR SCHWANGERSCHAFT, GEBURT UND LACTATION BEI DER RATTE

1970 ◽  
Vol 65 (3_Suppl) ◽  
pp. S5-S32 ◽  
Author(s):  
K. Loewit
Keyword(s):  
Luteinizing Hormone ◽  
Early Pregnancy ◽  
Hydroxysteroid Dehydrogenase ◽  
The State ◽  
Termination Of Pregnancy ◽  
Progesterone Level ◽  
Corpora Lutea ◽  
Regulatory Properties ◽  
Duration Of Pregnancy

ABSTRACT The role of luteinizing hormone (LH) for the maintenance of pregnancy, parturition and lactation was investigated by immunological and histochemical methods in the rat. Neutralisation of endogenous rat-LH with Rabbit-Anti-Bovine-LH-Serum (selective hypophysectomy) from days 7-12 of pregnancy resulted in reabsorption of the foetuses and the reappearance of strong 20α-hydroxysteroid-dehydrogenase (20α-OHSD) activity in the corpora lutea (CL) of pregnancy, which normally show no such activity at that time. This effect could be prevented in part by concurrent pregnenolone administration and fully by progesterone, but was not influenced by oestrogen or prolactin. It is concluded that in early pregnancy LH is the main luteotrophic hormone in the rat even though prolactin might act synergistically with it. Antiserum treatment after the 12th day of gestation had no influence on the state or duration of pregnancy or on parturition. LH-injections during the first half of pregnancy had no luteolytic effects i. e. they did not activate 20α-OHSD activity. After day 16 they advanced the reappearance of the enzyme, but delayed parturition or resulted in stillbirths. Neither LH nor antiserum seemed to alter lactation. Since progesterone prevented both the termination of pregnancy and the recurrence of 20α-OHSD activity, it should have some regulatory properties on the enzyme. It is discussed whether the gonadotrophin-dependent progesterone level could regulate the 20α-OHSD activity rather than result from it.

Stimulation of Ca(2+)-dependent exocytosis of the sperm acrosome by cAMP acting downstream of phospholipase A2

Reproduction ◽  
2000 ◽  
pp. 57-68 ◽  
Author(s):  
J Garde ◽  
ER Roldan
Keyword(s):  
Arachidonic Acid ◽  
Phospholipase A2 ◽  
Phospholipase C ◽  
Phosphodiesterase Inhibitors ◽  
Dibutyryl Camp ◽  
Camp Phosphodiesterase ◽  
Ram Sperm ◽  
Camp Formation ◽  
Stimulation Of

Spermatozoa undergo exocytosis in response to agonists that induce Ca2+ influx and, in turn, activation of phosphoinositidase C, phospholipase C, phospholipase A2, and cAMP formation. Since the role of cAMP downstream of Ca2+ influx is unknown, this study investigated whether cAMP modulates phospholipase C or phospholipase A2 using a ram sperm model stimulated with A23187 and Ca2+. Exposure to dibutyryl-cAMP, phosphodiesterase inhibitors or forskolin resulted in enhancement of exocytosis. However, the effect was not due to stimulation of phospholipase C or phospholipase A2: in spermatozoa prelabelled with [3H]palmitic acid or [14C]arachidonic acid, these reagents did not enhance [3H]diacylglycerol formation or [14C]arachidonic acid release. Spermatozoa were treated with the phospholipase A2 inhibitor aristolochic acid, and dibutyryl-cAMP to test whether cAMP acts downstream of phospholipase A2. Under these conditions, exocytosis did not occur in response to A23187 and Ca2+. However, inclusion of dibutyryl-cAMP and the phospholipase A2 metabolite lysophosphatidylcholine did result in exocytosis (at an extent similar to that seen when cells were treated with A23187/Ca2+ and without the inhibitor). Inclusion of lysophosphatidylcholine alone, without dibutyryl-cAMP, enhanced exocytosis to a lesser extent, demonstrating that cAMP requires a phospholipase A2 metabolite to stimulate the final stages of exocytosis. These results indicate that cAMP may act downstream of phospholipase A2, exerting a regulatory role in the exocytosis triggered by physiological agonists.

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