Changes in plasma concentrations of gonadotropin, 17β-estradiol, testosterone, and 17α-hydroxy-20β-dihydroprogesterone during spontaneous and brain lesion induced ovulation in goldfish

1983 ◽  
Vol 61 (12) ◽  
pp. 2646-2652 ◽  
Author(s):  
N. E. Stacey ◽  
R. E. Peter ◽  
A. F. Cook ◽  
B. Truscott ◽  
J. M. Walsh ◽  
...  
Keyword(s):  
Plasma Concentrations ◽  
Brain Lesion ◽  
Time Of Day ◽  
Plasma Testosterone ◽  
Anterior Portion ◽  
Potent Inducer ◽  
Induced Ovulation ◽  
Goldfish Carassius Auratus ◽  
Final Maturation ◽  
17Β Estradiol

Female goldfish (Carassius auratus) were held at 20–21 °C and ovulation was triggered by radiofrequency lesion of the anterior portion of the nucleus preopticus periventricularis (NPP) as in previous studies. NPP lesions induced a rapid and dramatic increase in blood gonadotropin (GtH) which reached peak levels between 9 and 15 h postlesioning and persisted for at least 48 h postlesioning. Unlike spontaneous ovulation, which is synchronized with photoperiod, NPP lesion-induced ovulation at 20–21 °C occurs 10–14 h postlesioning regardless of the time of day the operation is performed. 17α-hydroxy-20β-dihydroprogesterone, a potent inducer of oocyte final maturation in goldfish, could be detected in plasma of lesioned fish only at 5 h after the operation, Plasma testosterone levels peaked 2.5 h postlesioning (about 10 h prior to ovulation) and tended to decrease at subsequent sampling times. In contrast, peak levels of estradiol were not seen until 15 h postlesioning (several hours after ovulation). Pre- and post-ovulatory samples from spontaneously ovulating fish demonstrated a similar pattern of decreasing testosterone and increasing estradiol.

Conservation, Ecology, and Management of Catfish: The Second International Symposium

2011 ◽  
Keyword(s):  
Gonadosomatic Index ◽  
Gonadal Development ◽  
Reproductive Hormones ◽  
Wild Fish ◽  
Spawning Season ◽  
Plasma Testosterone ◽  
Anterior Portion ◽  
In Captivity ◽  
17Β Estradiol ◽  
Epaxial Muscles

<em>Abstract</em>.—Captive spawning is a strategy to bolster populations of rare madtoms <em>Noturus</em> spp., but very little is known regarding their reproductive development in captivity. The primary goal of this research was to develop methods to stimulate gonadal maturation of captive madtoms. We used the nonimperiled margined madtom <em>N. insignis</em> as a model species to investigate the effects of photothermal regimes on gonadal development and reproductive hormones. We also evaluated testicular development of madtoms injected with common carp <em>Cyprinus carpio</em> pituitary extract (CPE). Changing photoperiod, but not temperature, was required to induce oocyte maturation in a high percentage of captive female margined madtoms. Gonadosomatic index (GSI) values of captive females were similar to those of gravid wild fish collected during or just prior to the spawning season with the time to maturation of oocytes shortened by as much as 3 months. Many of the captive males developed large, square-shaped heads with swollen cephalic epaxial muscles as spawning conditions approached, but their GSI values were not different from those of fish sampled at other times of the year. Injections of CPE increased the GSI value and vascularization of testes but not the number of spermatozoa. In general, sperm production in mature male madtoms was enigmatic in captive and wild fish, inasmuch as motile sperm were observed only once. The heads of margined madtom spermatozoa are slightly ovate (4.3 0.2 μm long and 3.6 0.2 μm wide). The tails are centrally attached to the head and are more than 112.5 μm long. A pronounced, collar-like midpiece encircles the posterior portion of the head and anterior portion of the tail. Plasma testosterone concentrations in males peaked just prior to the spawning season at 6.5 ng/mL, but levels were not correlated with male GSI values. Plasma 17β-estradiol levels in females peaked just prior to the spawning season at 15 ng/mL and were correlated with gonadosomatic values.

TESTICULAR FUNCTION IN STRAINS OF MICE SELECTED FOR DIFFERENCES IN GONADOTROPHIN-INDUCED OVULATION RATE

1981 ◽  
Vol 90 (3) ◽  
pp. 367-373 ◽  
Author(s):  
H. G. WOLFE ◽  
A. BARTKE ◽  
A. AMADOR ◽  
MARY VAN SICKLE ◽  
SUSAN DALTERIO ◽  
...  
Keyword(s):  
Binding Sites ◽  
Plasma Concentrations ◽  
Ovulation Rate ◽  
Plasma Testosterone ◽  
Induced Ovulation ◽  
Testicular Weight ◽  
Seminal Vesicle Weight ◽  
Selection For ◽  
Pregnant Mare Serum Gonadotrophin

Mice were selected on the basis of ovulatory responses to injections of pregnant mare serum gonadotrophin (PMSG) and human chorionic gonadotrophin (hCG). Various parameters of pituitary and gonadal function as well as responsiveness to exogenous gonadotrophins were examined in males from high induced-ovulation rate (HIOV) and low induced-ovulation rate (LIOV) lines. Testicular weight, seminal vesicle weight and plasma LH levels were lower in HIOV than in LIOV males, while plasma concentrations of FSH and testosterone did not differ. Binding of FSH, but not of LH, in the testes was significantly higher in HIOV mice. Twenty-four hours after administration of hCG, plasma testosterone levels were higher and testicular LH binding sites appeared more depleted in HIOV than in LIOV males. Production of testosterone by decapsulated testes in vitro was significantly higher in HIOV than in LIOV mice under basal conditions, as well as in the presence of LH, FSH, hCG or PMSG. It was concluded that selection for differences in gonadotrophin-induced ovulation rate produced correlated differences in the steroidogenic response of the testes to gonadotrophins and that these differences may be due to divergence in the number of gonadal FSH binding sites.

17α,20β-Dihydroxy-4-pregnen-3-one: a steroidal primer pheromone increasing milt volume in the goldfish, Carassius auratus

1986 ◽  
Vol 64 (11) ◽  
pp. 2412-2417 ◽  
Author(s):  
N. E. Stacey ◽  
P. W. Sorensen
Keyword(s):  
Carassius Auratus ◽  
Primer Pheromone ◽  
Goldfish Carassius Auratus ◽  
Final Maturation ◽  
17Β Estradiol ◽  
Releaser Pheromone

The volume of milt that could be stripped from male goldfish, Carassius auratus, increased dramatically when fish were exposed overnight to water with concentrations of 17α,20β-dihydroxy-4-pregnen-3-one (17,20P) as low as 10−10 M. A variety of free steroids (pregnenolone, androstenedione, testosterone, 11-ketotestosterone, 17β-estradiol) and glucuronated steroids (etiocholanolone glucuronide, testosterone glucuronide, 17β-estradiol glucuronide), suggested by others to function as pheromones in fish, failed to increase milt volume at a concentration of 5 × 10−9 M. The milt response appears to be specific to 17,20P and progesterone precursors (17α-hydroxyprogesterone, progesterone), but is most sensitive to 17.20P. Because bilateral section of the olfactory tracts completely blocked the milt response to 17.20P, it is believed to be a pheromone. Selective sectioning of the lateral and medial subdivisions of the olfactory tracts demonstrated that the milt response to 17,20P is dependent on the medial tract. Increases in milt in response to 17,20P are not affected by interaction with conspecifics; exposure to 17,20P induced equivalent responses in males held in isolation, paired with a male, or paired with a female. It is proposed that 17,20P, which is produced during oocyte final maturation in the female, is a "primer" pheromone released to the water and that it increases milt volume in the male. This effect is discussed in relation to releaser pheromone effects previously demonstrated in goldfish.

INFLUENCE OF METYRAPONE ON PLASMA CONCENTRATIONS OF TESTOSTERONE AND ANDROSTENEDIONE IN MAN

1971 ◽  
Vol 68 (3) ◽  
pp. 576-584 ◽  
Author(s):  
K. O. Nilsson ◽  
B. Hökfelt
Keyword(s):  
Body Weight ◽  
Male Patient ◽  
Gradual Increase ◽  
Plasma Concentrations ◽  
Plasma Testosterone ◽  
Testosterone Levels ◽  
Basal Plasma ◽  
Normal Males ◽  
A Minor ◽  
Secondary Hypogonadism

ABSTRACT Metyrapone was administered either orally, 750 mg every four h, in a total of six doses, or intravenously 30 mg per kg body weight as a four h infusion. In three males with normal endocrine functions, metyrapone given orally or intravenously induced a fall in plasma testosterone and an elevation of androstenedione within 2–8 h. When metyrapone was administered to a patient given dexamethasone to suppress endogenous ACTH production, the androstenedione levels did not alter whereas the testosterone levels showed a slight, transient decrease. In two normal females metyrapone administration was followed by a marked increase in plasma androstenedione whereas testosterone showed only a minor, gradual increase. In one male patient with Addison's disease the basal plasma testosterone was normal whereas the level of androstenedione was low. Following metyrapone intravenously, there was a slight suppression of plasma testosterone but no change in the androstenedione concentration. In one patient with primary hypogonadism, two with secondary hypogonadism and two with Klinefelter's syndrome the plasma testosterone was low under basal conditions and did not change following metyrapone. Basal plasma androstenedione was within the range for normal males and increased markedly following metyrapone in all the cases.

Pituitary and gonadal responses to the long-term pulsatile administration of gonadotrophin-releasing hormone in fetal fetal sheep

1997 ◽  
Vol 153 (3) ◽  
pp. 385-391 ◽  
Author(s):  
G B Thomas ◽  
A N Brooks
Keyword(s):  
Plasma Concentrations ◽  
Reproductive Function ◽  
Inverse Correlation ◽  
Experimental Period ◽  
Immediate Release ◽  
Late Gestation ◽  
Plasma Testosterone ◽  
Fetal Sheep ◽  
Pulsatile Administration

Abstract The fetal hypothalamo–pituitary–gonadal axis reaches a peak in activity at mid-gestation and this is followed by a period of suppression which persists until the onset of puberty. The decline in gonadotrophic activity during late gestation is thought to reflect the maturation of central and peripheral feedback signals. In order to establish if sustained pituitary responsiveness is rate limiting to the reinstatement of reproductive function, we have examined the endocrine consequences of repeated pulsatile GnRH administration to male and fetal sheep during late gestation. Beginning on day 121 of gestation (term=145 days) chronically catheterized fetal sheep were given i.v. pulses of either 500 ng GnRH or saline every 2 h for 14 days. Pituitary and gonadal responses were assessed by measuring changes in plasma concentrations of LH, FSH, inhibin and testosterone (in male fetuses) in response to the first pulse of GnRH on day 1 and to the corresponding pulse on days 4, 7, 10 and 14. In response to the first pulse of GnRH there was an immediate release of LH, with the peak response being significantly (P<0·01) greater than on subsequent days. In male fetuses each pulse of LH was followed by a rise in plasma testosterone concentrations within 40–60 min. The amplitude of these testosterone responses increased significantly (P<0·01) after 9 days of treatment despite a decline in the plasma LH response. Basal FSH concentrations increased progressively (P<0·05) during pituitary stimulation with GnRH in both male and female fetuses. Immunoreactive inhibin concentrations were significantly (P<0·05) higher in males than in females, and there was a gradual increase throughout the experimental period irrespective of treatment. We observed no inverse correlation between inhibin and FSH concentrations. These data show that pulsatile administration of GnRH to fetal sheep during late gestation results in sustained re-activation of pituitary–gonadal function. The decline in fetal gonadotrophins, which is a characteristic feature of late gestation, is therefore likely to result from inadequate GnRH secretion from the fetal hypothalamus rather than an inhibition of pituitary function by peripheral feedback signals. Journal of Endocrinology (1997) 153, 385–391

scholarly journals The reproductive hormone cycle of adult female American alligators from a barrier island population

Reproduction ◽  
2014 ◽  
Vol 147 (6) ◽  
pp. 855-863 ◽  
Author(s):  
Heather J Hamlin ◽  
Russell H Lowers ◽  
Satomi Kohno ◽  
Naoko Mitsui-Watanabe ◽  
Haruna Amano ◽  
...  
Keyword(s):  
Adult Female ◽  
Plasma Concentrations ◽  
Barrier Island ◽  
Reproductive Activity ◽  
Plasma Testosterone ◽  
Island Population ◽  
Moderate Increase ◽  
Random Intervals ◽  
American Alligators ◽  
Kennedy Space

Comparatively, little data are available detailing the geographic variation that exists in the reproductive endocrinology of adult alligators, especially those living in barrier islands. The Merritt Island National Wildlife Refuge (MI) is a unique barrier island environment and home to the Kennedy Space Center (FL, USA). Seasonal patterns of sex steroids were assessed in adult female American alligators from MI monthly from 2008 to 2009, with additional samples collected at more random intervals in 2006, 2007, and 2010. Plasma 17β-estradiol and vitellogenin concentrations peaked in April, coincident with courtship and mating, and showed patterns similar to those observed in adult female alligators in other regions. Plasma concentrations of progesterone, however, showed patterns distinctly different than those reported for alligator populations in other regions and remained relatively constant throughout the year. Plasma DHEA peaked in July around the time of oviposition, decreased in August, and then remained constant for the remaining months, except for a moderate increase in October. Circulating concentrations of DHEA have not been previously assessed in a female crocodilian, and plasma concentrations coincident with reproductive activity suggest a reproductive and/or behavioral role. Interestingly, plasma testosterone concentrations peaked in May of 2008, as has been shown in female alligator populations in other regions, but showed no peak in 2009, demonstrating dramatic variability from year to year. Surveys showed 2009 to be particularly depauperate of alligator nests in MI, and it is possible that testosterone could serve as a strong indicator of breeding success.

scholarly journals Inhibin is an important factor in the regulation of FSH secretion in the adult male hamster

2000 ◽  
Vol 278 (4) ◽  
pp. E744-E751 ◽  
Author(s):  
Hisashi Kishi ◽  
Mariko Itoh ◽  
Sachiko Wada ◽  
Yoko Yukinari ◽  
Yumiko Tanaka ◽  
...  
Keyword(s):  
Adult Male ◽  
Leydig Cells ◽  
Initial Level ◽  
Plasma Concentrations ◽  
Plasma Testosterone ◽  
Gonadotropin Secretion ◽  
Α Subunit ◽  
Male Golden Hamsters ◽  
Lh Secretion

We investigated the importance of inhibin and testosterone in the regulation of gonadotropin secretion in adult male golden hamsters ( Mesocricetus auratus). After castration, plasma concentrations of inhibin and testosterone were reduced to undetectable, whereas plasma follicle-stimulating hormone (FSH) and luteinizing hormone (LH) were increased. After hemicastration, plasma FSH and LH increased moderately and plasma inhibin decreased to one-half its initial level. Plasma testosterone levels in hemicastrated animals decreased 3 h after hemicastration but returned to those in sham-operated animals at 6 h. Plasma LH in the castrated hamster declined comparably to intact animals with testosterone treatment; plasma FSH also decreased but still remained at levels higher than those in intact animals. After treatment with inhibin in long-term-castrated animals, plasma FSH decreased, whereas plasma LH was not altered. Intact males treated with flutamide, an anti-androgen, showed a significant increase in plasma LH but not in FSH. On the other hand, treatment with anti-inhibin serum induced a significant elevation in plasma FSH, but not in LH. Using immunohistochemistry, we showed that the inhibin α-subunit was localized to both Sertoli and Leydig cells. The present study in adult male hamsters indicates that FSH secretion is regulated mainly by inhibin, presumably from Sertoli and Leydig cells, and that LH secretion is controlled primarily by androgens produced from the Leydig cells. This situation is more similar to that of primates than of rats.

The relationship between plasma testosterone concentrations and the seasonal variation in voluntary feed intake in fallow bucks (Dama dama)

1998 ◽  
Vol 130 (3) ◽  
pp. 357-366 ◽  
Author(s):  
R. E. NEWMAN ◽  
S. J. McCONNELL ◽  
R. H. WESTON ◽  
M. REEVES ◽  
C. BERNASCONI ◽  
...  
Keyword(s):  
Feed Intake ◽  
Plasma Concentrations ◽  
Plasma Free Fatty Acid ◽  
Reproductive Behaviour ◽  
Fallow Deer ◽  
Plasma Testosterone ◽  
Control Group ◽  
Voluntary Feed Intake ◽  
Natural Photoperiod ◽  
The Relationship

In two experiments conducted at Badgery's Creek, NSW (Latitude 34°S) the roles of testosterone and the thyroid hormones triiodothyronine (T3) and thyroxine (T4) as possible initiators of the change in voluntary feed intake (VFI) associated with the seasonal reproductive behaviour (rut) in male fallow deer were investigated.In Expt 1, the association between changes in these hormones with the onset of the rut was assessed in deer in which the timing of this event was manipulated by changing the photoperiod, or by melatonin administration. Groups were maintained under either natural photoperiod (n=6; control), a constant long daylength (16 h light[ratio ]8 h dark; n=9; LD group) or a constant long daylength and implanted with melatonin capsules (n=5; LD+M group) for 7 months from December until the following July. Blood samples were obtained weekly and VFI recorded.Feed intake decreased by 94% from the last week of March for 3 weeks in the control group. Changes of a similar magnitude were measured in the LD and LD+M groups but these changes were advanced by 1 and 9 weeks respectively in these groups. In all groups, circulating testosterone concentrations increased markedly at a time corresponding with the decrease in VFI. The concentrations returned to basal levels with the resumption in VFI. A distinct decrease in plasma concentrations of T3 and T4 in all three groups was associated with the decrease in VFI, however, the relationship with T3 was less apparent.In Expt 2, the role of testosterone in the regulation of the decline in VFI was investigated. Fallow bucks were treated with testosterone enanthate every 4 or 5 days for 28 days up to 6 weeks prior to the expected onset of the rut. Plasma testosterone concentrations, which were increased 13-fold, resulted in a decline in VFI which was comparable to that observed in the subsequent rut. Plasma free fatty acid concentrations were correlated negatively with the decline in VFI.Thus, the seasonal increase in circulating testosterone concentrations plays an important role in initiating the fall in VFI associated with the rut. As the rut was still apparent in animals maintained under an extended photoperiod, it is possible that factors other than decreasing daylength act as the cue for the timing of the rut.

Plasma steriod hormone concentrations in relation to reproductive cycle of the sweep Scorpis lineolatus (Kyphosidae) caught from the wild

1992 ◽  
Vol 43 (4) ◽  
pp. 753 ◽  
Author(s):  
M Deual ◽  
NW Pankhurst
Keyword(s):  
Steroid Hormones ◽  
Reproductive Cycle ◽  
Gonadosomatic Index ◽  
Plasma Concentrations ◽  
Plasma Testosterone ◽  
Hepatosomatic Index ◽  
Spawning Period ◽  
Testosterone Concentration ◽  
Low Concentrations ◽  
Advanced Stages

Changes in gonadosomatic index (GSI), hepatosomatic index (HSI), oocyte development and plasma levels of steroid hormones were studied during the reproductive cycle of the sweep Scorpis lineolatus. GSI values for both sexes were maximal in March and April. During this period the size distribution of oocytes showed a predominance of advanced stages of vitellogenesis, whereas males were completing spermatogenesis. However, staging data suggest that spawning may not begin until April. HSI was maximal 2 months prior to the beginning of gametogenesis in both sexes. Plasma concentrations of oestradiol-17β in females increased rapidly from February, reached a peak (2.3 ng mL-1) in association with the end of vitellogenesis in March, and returned to low concentrations in May and June. Plasma concentrations of 17α,20α-dihydroxy-4-pregnen-3-one (17,20βP) also peaked in March in females, but 17,20βP was generally not detectable in males. Plasma testosterone concentration peaked along with other steroids in March in females but showed no significant change in males. Plasma ll-ketotestosterone (1 1KT) concentration was maximal in males before spawning (February), but was not elevated during the spawning period itself. Changes in oestradiol-17β and testosterone in association with vitellogenensis in females are consistent with those reported for other teleosts, whereas changes in 17,20βP, testosterone and 11-ketotestosterone in males are different from those previously reported.

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