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Results for “luteinizing hormone”

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At least 19 recordsLinked to original sources
PubMed1976

Correlation between follicle stimulating hormone, luteinizing hormone, testosterone and 5-hydroxyindole acetic acid with sperm cell concentration.

Plasma follicle stimulating hormone, luteinizing hormone, testosterone, urinary 5-hydroxyindole acetic acid and 17-ketosteroids were measured in patients seen at an infertility clinic. Plasma follicle stimulating hormone and luteinizing hormone levels, and urinary 5-hydroxyindole acetic acid levels were increased in patients with sperm concentrations less than 10 times 10(6) per ml. The results suggest that in patients with sperm counts less than 10 times 10(6) per ml. there is not only impaired spermatogenesis but also decreased Leydig cell function. Urinary 17-ketosteroid levels were not related to sperm cell concentration.

17-Ketosteroids↗
PubMed1977

Pituitary-ovarian relationships preceding the menopause. I. A cross-sectional study of serum follice-stimulating hormone, luteinizing hormone, prolactin, estradiol, and progesterone levels.

Serum follicle-stimulating hormone (FSH), luteinizing hormone (LH), prolactin, estradiol, and progesterone concentrations were measured in 58 ovulating women in different age groups (20 to 29, 34 to 39, 40 to 44, and 45 to 50 years) at five- to seven-day intervals through a single menstrual cycle and in 18 postmenopausal women sampled weekly five to six times. The over-all hormone patterns were similar in four premenopausal groups. However, mean serum FSH levels increased with age and significantly higher concentrations were found in the 40 to 50 years group than in the 20 to 29 year group. Serum LH levels did not show a similar rise with age, although follicular LH levels in the oldest group were higher than in the 20 to 29 year group. Prolactin and estradiol concentrations did not change with age prior to the menopause, but luteal progesterone levels were lower in the three older premenopausal groups than in the 20 to 29 year group. Postmenopausal women showed elevated FSH and LH, decreased prolactin, and negligible estradiol and progesterone levels. There was an over-all significant linear correlation between prolactin and estradiol concentrations. It appears that the menopause is preceded by several years of rising gonadotropin, predominantly FSH, levels. During this period, ovarian estrogen production appears to be maintained and ovulation continues, but luteal progesterone levels decline. It is likely that these premenopausal alterations in pituitary-ovarian relationships reflect depletion of ovarian follicles.

Adult↗
PubMed1978

Effect of premenopausal castration and incremental dosages of conjugated equine estrogens on plasma follicle-stimulating hormone, luteinizing hormone, and estradiol.

Plasma levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), and estradiol (E2) were measured serially in 11 premenopausal patients before and after hysterectomy with bilateral salpingo-oophorectomy. One week after operation an incremental dosage regimen of conjugated estrogens (CEE) in tablet form was commenced on a basis of two weeks with therapy (0.3, 0.625, 1.25, and finally 2.5 mg.), with each dose interspersed by two weeks without therapy. FSH, LH and E2 levels were measured at the end of each period with and without therapy. E2 levels fell within 24 hours of operation while FSH and LH levels rose gradually. CEE therapy produced an elevation of E2, but circulating concentrations comparable to the premenopausal values were only maintained during the dosage periods of 0.625 and 1.25 mg. of CEE. In only one instance did CEE succeed in reducing FSH to premenopausal levels, and that was at a dosage of 2.5 mg., in which instance the E2 level was higher than the premenopausal value. LH was never reduced to a premenopausal level. Thus, the data indicate that CEE alone in dosages up to 2.5 mg. per day was unable to reproduce in postmenopausal women the gonadotropin and E2 blood serum levels shown to exist prior to oophorectomy. Usual CEE treatment after menopause, therefore, in itself does not represent physiologic "hormone replacement therapy," if defined as the dosage required to maintain premenopausal circulating concentrations of reproductive hormones.

Castration↗
PubMed1977

Influence of gonadotropic releasing hormone, luteinizing hormone and pineal extracts on testes of immature cockerels.

Two, seven, and ten-day-old S.C.W.L. cockerels were injected with pineal extract (PE), gonadotropic releasing hormone (GnRH) and luteinizing hormone (LH), alone or in combination, to determine the effect of PE on the action of exogenous GnRH and LH on the testis in immature cockerels. Radioactive phosphorus (P-32) uptake by the testis was used as an assay for gonadotropic activity. GnRH had no effects on cockerels aged two days. However, LH caused increased P-32 uptake compared to the saline control at this age. In seven- and ten-day-old cockerels, PE in combination with GnRH resulted in lower P-32 c.p.m./g. of testis compared to the non-PE treated birds at the same doses of GnRH. On the other hand, PE did not cause any decrease in testis response to LH. These results indicate that PE is acting to inhibit release of gonadotropins by GnRH.

Animals↗
PubMed1978

Follicle-stimulating hormone, luteinizing hormone, and testosterone levels found in human seminal plasma.

Radioimmunoassays were performed on the seminal plasma of normospermic, oligospermic, and azoospermic men to determine the levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH), and testosterone. FSH levels in the seminal plasma of all three groups were found to be similar to the levels normally found in blood serum. LH levels in the seminal plasma of azoospermic and oligospermic men were within the normal range found in blood serum but were elevated in the normospermic samples. Testosterone levels in the seminal plasma of all three groups tested were considerably lower than the normal range found in blood serum.

Follicle Stimulating Hormone↗
PubMed1976

Serum follicle-stimulating hormone, luteinizing hormone and progesterone concentrations in pseudopregnant rats treated with medroxyprogesterone acetate.

Pseudopregnant rats were treated early in pseudopregnancy with 1 or 10 mg medroxyprogesterone acetate (MPA). Serum FSH, LH and progesterone concentrations were determined on days 2-20 of pseudopregnancy in treated and control rats. The mean duration of pseudopregnancy was 13-5 days in the control animals, but when animals were treated with 1 mg MPA a dioestrous period of 21-4 days was observed. A period with leucocytic vaginal smears of at least 2 months was observed after treatment with 10 mg MPA. Injection with MPA on day 3 of pseudopregnancy did not affect the serum FSH concentrations during the subsequent days. The progesterone pattern was alike in the three groups of animals, i.e. the duration of the activity of the corpora lutea was similar in all groups. However, 10 mg MPA slightly lowered progesterone concentrations on days 4-8 of pseudopregnancy. In the saline-treated rats, LH concentrations decreased from days 2-5, and remained low until they increased after day 11 of pseudopregnancy. This increase was delayed until day 20 in the animals treated with 1 mg MPA, and was not observed in the animals treated with 10 mg MPA. It is argued that the increase of LH concentration at the end of pseudopregnency is not instrumental in the decrease of peripheral progesterone concentration but rather that the decrease in the progesterone concentration leads to the increase in the LH concentration.

Animals↗
PubMed1977

Effects of starvation in rats on serum levels of follicle stimulating hormone, luteinizing hormone, thyrotropin, growth hormone and prolactin; response to LH-releasing hormone and thyrotropin-releasing hormone.

Adult male Sprague-Dawley rats averaging 300 g each were subjected to complete food removal for 7 days (acutely starved), 7 days complete food removal followed by 2 weeks of 1/4 ad libitum food intake (chronically strved), 7 days complete food removal and 2 weeks of 1/4 ad libitum intake followed by ad libitum feeding for 7 days (refed), or fed ad libitum throughout (controls). Serum LH, FSH, TSH, PRL, and GH levels were measured by radioimmunoassays for each group of rats. The in vivo response to the combination of synthetic LHRH and TRH also was tested in each group of rats. Circulating LH, TSH, GH, and PRL were significantly depressed in acutely and chronically starved rats, and FSH was lowered only in acutely starved rats. After 7 days of refeeding, serum levels of LH and FSH were significantly greater than in ad libitum fed controls, PRL returned to control levels, and TSH and GH increased but were still below control levels. After LHRH + TRH injection serum LH and TSH were increased significantly in all groups of rats, FSH and PRL rose in acutely but not in chronically starved rats, and GH was not elevated in any group. The increases in serum LH, FSH, TSH and prolactin in response to LHRH + TRH injection in acutely or chronically starved rats were equal to or greater than in the ad libitum fed controls. These data indicate that severe reductions in food intake result in decreased release of at least 5 anterior pituitary hormones, and this is due primarily to reduced hypothalamic stimulation rather than to inability of the pituitary to secrete hormones.

Adrenal Glands↗
PubMed1977

Photoperiodic control of gonadotrophin secretion in the ram: a detailed study of the temporal changes in plasma levels of follicle-stimulating hormone, luteinizing hormone and testosterone following an abrupt switch from long to short days.

Six adult Soay rams were housed under artificial lighting conditions of long days (16 h light:8 h darkness) for 4 months and this caused the animals to lapse into a state of reproductive quiescence with low levels of gonadotrophins in the circulation and regressed testes secreting very low amounts of testosterone. The photoperiod was changed abruptly to short days (8 h light:16 h darkness) to induce a resurgence of sexual activity, and a detailed study was made of the pituitary and testicular responses over the first 100 days. Plasma levels of LH and FSH first began to increase between days 6 and 12 of short days, and rose progressively until days 33-54 before declining again. Testicular growth of the rams began on days 19-26 and continued for most of the remaining period of study. Plasma testosterone levels rose in parallel with the growth of the testes, and were greatly increased by day 100 when gonadotrophin levels were reduced. At most stages there were short-term fluctuations in the plasma levels of FSH, LH and testosterone indicative of episodic secretion. Peaks in plasma levels of LH were especially conspicuous and from the changes in frequency and amplitude of these peaks it was possible to predict the way in which photoperiod influenced gonadotrophin secretion by its effect on hypothalamic LH-RH secretion. A slight 24 h rhythm in the plasma levels of all three hormones was observed, and the significance of this in relation to the photoperiodic response is discussed.

Animals↗
PubMed1978

Prolactin, growth hormone, luteinizing hormone receptors, and seasonal changes in testicular activity in the golden hamster.

In adult male hamsters, 2 months of exposure to a short photoperiod (5 h of light:19 h of darkness) caused testicular regression and a precipitous decline in plasma PRL, in agreement with earlier reports from other laboratories. Depressed release of PRL cannot be explained by a reduction in testicular steroidogenesis, because castration of males kept in a long photoperiod did not reduce PRL levels and administration of testosterone to males kept in a short photoperiod failed to reverse the decline in plasma PRL concentration. Treatment of such "regressed" animals with PRL, GH, or ectopic pituitary transplants stimulated growth of the testes and the accessory reproductive glands, increased the concentration of LH receptors in the testes, and elevated plasma testosterone levels. A single injection of 250 microgram PRL was sufficient to increase testicular LH binding, and chronic treatment with pituitary grafts completely reversed testicular regression. The effectiveness of exogenous PRL in stimulating testicular growth and LH receptors was significantly influenced by the timing of the injection. In some experiments, gonadotropin levels appeared elevated in animals injected with PRL, but these differences were not statistically significant. In hamsters with gonadal regression induced by exposure to a short photoperiod, daily administration of 20 microgram H and/or 150 microgram FSH had no apparent effect on testicular function. However, treatment with large doses of hCG and/or PMS gonadotropin resulted in significant stimulation of testicular growth and steroidogenesis. Chronic treatment of males maintained in a long photoperiod (14 h of light:10 h of darkness) with an inhibitor of PRL release, 2-Br-alpha-ergocryptine, resulted in a decreased weight of the testes and seminal vesicles. Administration of this inhibitor for a longer period (2 months) produced a significant increase in body weight but had little effect on testicular function. These results indicate that changes in the release of PRL (and possibly also GH) may plan an important role in mediating the effects of the photoperiod on testicular function in the golden hamster.

Animals↗
PubMed1977

Seasonal and circadian changes in the episodic release of follicle-stimulating hormone, luteinizing hormone and testosterone in rams exposed to artificial photoperiods.

Six rams of an ancient breed of domesticated sheep (SOAY) were subjected to an artificial light régime of alternating periods of long days (16 h light: 8 h darkness) and short days (8 h light: 16 h darkness) which induced seasonal development and regression of the testes during a period of 36 weeks. Over 2000 blood samples were taken, and the changes in plasma levels of FSH, LH and testosterone were related to the cycle of testicular activity. During long days plasma levels of gonadotrophins became very low and the testes regressed to about 20% of their maximum size; there was a corresponding reduction in plasma testosterone levels. When the rams were returned to short days reproductive development was again stimulated after 2-3 weeks with a progressive increase in plasma FSH and LH levels and consequent hypertrophy of the testes. It took about 16 weeks of short days for testicular activity to become maximal. Blood samples collected at hourly intervals for 24 h on ten occasions during the study revealed transitory peaks in plasma FSH and LH levels indicative of episodic release. Changes in gonadotrophin secretion were modulated primarily by alterations in the frequency of episodic releas; less than 1 spike per 24 h during long days increased to a maximum of 10 spikes/24 h under short daylengths. The peaks of FSH release were of smaller amplitude than those of LH, although during periods of frequent episodic release basal levels of fsh were increased to a greater extent than those of LH. A circadian rhythm was observed in the plasma levels of FSH, LH and testosterone, which was related to increased gonadotrophin release during the dark phase of the 24 h cycle; changes in blood haematocrit were also observed. The circadian changes appeared to be correlated with the activity cycle of the animals which in turn was dictated by daylight. A possible interrelationship between the circadian cycle and the seasonal cycle is discussed.

Animals↗
PubMed1976

Production of antisera against highly purified human follicle-stimulating hormone, luteinizing hormone and thyroid-stimulating hormone.

Antisera were produced in rabbits against highly purified preparations of human LH (2000 or 10,000 i.u./mg), human FSH (5500 i.u./mg), and human TSH (7-5 i.u./mg). Most rabbits produced antisera of high titre and high avidity. Cross-reactions were minimal between human TSH and human chorionic gonadotrophin (HCG) and between human FSH and HCG but marked between human LH and HCG. TSH and FSH also showed a constant but relatively weak cross-reaction. LH cross-reacted with FSH to a higher degree than did HCG. The avidity of the antisera was high. It was concluded that much of the lack of specificity recorded for glycoprotein antisera are effects of impure immunogens. Some of the true cross-reactions are probably explained by shared antigenic determinants of the beta-subunits. Unadsorbed antisera could be used for assay of FSH and TSH in plasma from pregnant women.

Animals↗
PubMed1977

Influence of foetal genotype on the follicle-stimulating hormone:luteinizing hormone ratio of pregnant mare serum gonadotrophin.

Rat testicular radioreceptor assays specific for FSH and LH were used to determine the FSH:LH ratio of PMSG produced by horse, donkey, mule and hinny conceptuses. Measurements of FSH and LH activities in PMSG produced both in vivo and in vitro by the four types of conceptuses showed that the genotype of the foetus markedly influences the FSH:LH ratio of PMSG. The FSH:LH ratio of PMSG produced by the horse conceptus was around unity whereas the ratio of PMSG produced by the donkey conceptus was as low as 0-2. Furthermore, the hybrid mule and hinny conceptuses both produced PMSG with an FSH:LH ratio which was approximately midway between those of the horse and donkey.

Animals↗
PubMed1977

Effects of luteinizing hormone releasing hormone on plasma follicle-stimulating hormone and luteinizing hormone levels in the ferret.

Heterologous radioimmunoassays for FSH and LH were employed to examine the effect of synthetic LH-RH upon gonadotrophin secretion in the ferret. Intravenous injection of 4 microng LH-RH induced a surge of FSH and of LH secretion in male and in female animals. In intact and in castrated males, the rise of LH was much more marked than that of FSH. The gonadotrophin response to LH-RH was greater in anoestrous than in oestrous females; FSH secretion was not enhanced during oestrus. Ovariectomized females behaved as anoestrous females with respect to LH secretion, while FSH secretion remained unchanged. Treatment of ovariectomized females with progesterone did not alter the pattern of response to LH-RH, but oestradiol treatment depressed the reaction to match that seen in oestrous females. Repetitive injections of LH-RH induced repetitive surges of FSH and LH in anoestrous females, but only of LH during oestrus: slow i.v. infusion of LH-RH induced a sustained elevation of plasma LH levels both in oestrous and in anoestrous females; again FSH levels rose only in anoestrous females. Injection of synthetic TRH did not alter gonadotrophin secretion in corresponding groups of male or female ferrets.

Animals↗