Gonadotropic Activity Research Articles

Spermatogenesis in leeches I. Evidence for a gonadotropic peptide hormone produced by the supraoesophageal ganglion of Erpobdella octoculata

juvenile Erpobdella octoculata were ligated and decerebrated by removal of the first few head segments. Decerebration resulted in the arrest of spermatogensis. Injection of homogenates of supreoesophageal ganglia resulted in the resumption of spermatogenesis; homogenates of oehter nervous tissues were much less effective. Further subdivision of the supraoesophageal ganglion revealed that the gonadotropic activity resided in one compartment of nerve cells. This compartment is rich in putative neurosecretory cells. Heat treatment of supraoesophageal ganglia homogenates did not destroy the gonadotropic activity but treatment with trypsin did. The data support the concept of a gonadotropic peptide hormone, produced in one compartment of nerve cells in the supraoesophageal ganglion stimulating spermatogenesis in E. octoculata.

Effects of teleost gonadotropins and their antibodies on gonadal histology in winter flounder

The gonadotropic actions of teleost vitellogenic and maturational hormones were studied in flounder hypophysectomized shortly after reinitiation of vitellogenesis and spermatogenesis in August. Maturational hormone alone was able to stimulate formation of yolky oocytes, but vitellogenic hormone required the action of estrogen before it could stimulate production of yolky oocytes. An antiserum to vitellogenic hormone induced atresia of yolky oocytes and lowered the gonadosomatic index in vitellogenic flounder whereas an antiserum to maturational hormone did not affect ovarian histology or gonadosomatic index to any great extent. Preincubation of flounder ovarian sections with vitellogenic hormone, followed by incubation with antiserum to vitellogenic hormone and fluorescein isothiocyanate-labeled goat-anti-rabbit γ-globulin in succession, resulted in immunofluorescence in ooplasm of both large immature and vitellogenic oocytes, and in follicular envelopes of vitellogenic oocytes. Preincubation of ovarian sections with maturational hormone resulted in fluorescence in the interstitial tissue, and the follicular envelopes and the perinuclear regions of yolky oocytes. Maturational hormone stimulated spermatogenesis in hypophysectomized male flounder. The significance of these results in relation to previous studies was discussed.

Effect of hCGB-tt immunization on ovarian morphology in hamsters implanted with human chortocarcinoma

Histological analysis of ovaries from hamsters immunized with hCGB-tt and implanted with human choriocarcinoma has shown that the gonadotropic activity of hCG was neutralized for 5 days of tumor growth. In control immunized hamsters, hCG secreted from the tumor induced the formation of large, cystic follicles, thecal luteinization and an increase in ovarian masn from Days 1–10 of tumor growth. In contrast, ovatian morphology in hCGB-tt immunized hamsters on Days 1–5 of tumor growth resembled that of non-tumor bearing hamsters. Normal follicular growth and corpora luted formation were observed despite the secretion of hCG by the tumor. Gonadotropic stimulation, as indicated by the presence of cystic follicles, was not evident until Day 10 of tumor growth in hamsters immunized with hCGB-tt. hCGB-tt immunization did not affect ovarian structure or the normal eatrus cycle in hamsters without tumors. These results indicate that the biological activity of hCG in vivo can be inhibited by active immunization with hCGB-tt.

Interaction of crude and pure chorionic gonadotropin with the thyrotropin receptor.

The effect of crude and pure hCG preparations on bovine TSH (bTSH) binding to its receptor was investigated in an attempt to characterize further the intrinsic thyrotropic activity of hCG. In a TSH radioreceptorassay with bovine thyroid membranes, performed at 4 C without NaCl in the incubation medium, the cross-reactivity of a crude hCG preparation was 90% relative to unlabeled bTSH, whereas that of pure hCG and its subunits was below 0.01%. By Sephadex G-100 chromatography, the substances in crude hCG that displayed TSH binding inhibitory activity at 4 C exhibited great heterogeneity, with an apparent molecular size range of 6,000-70,000 daltons. No specific peaks of TSH binding inhibitory substances were observed in the elution region of hCG, TSH, or molar or chorionic TSH, and most of the inhibitory substances had apparent molecular sizes smaller than any known TSH. When the radioreceptorassay was performed under progressively more physiological conditions by raising the temperature to 37 C and adding NaCl to the incubation buffer, the crossreactivity of crude and pure hCG relative to bTSH fell to 0.003- 0.005% both with bovine and human thyroid membranes. The similar effects of crude and pure hCG under near physiological incubation conditions suggested that the active substance in the crude hCG preparation was indeed hCG, whereas the effect of the other substances in the preparation had been abolished. Under such conditions, no cross-reactivity of hCG subunits was observed, whereas the cross-reactivity of human TSH was 10%, that of human LH was 0.3%, and that of human FSH was 0.1% relative to bTSH. Based on the TSH radioreceptorassay performed under near physiological incubation conditions, resulting in maximal TSH sensitivity and specificity, the thyrotropic activity of 1 IU (gonadotropic activity) of hCG is thus equivalent to 0.05-0.08 juIU bTSH.

Neutralization of the gonadotropic effects of human chorionic gonadotropin secreted by human choriocarcinoma transplanted in hamsters actively immunized against the beta-subunit of human chorionic gonadotropin coupled to tetanus toxoid.

The effect of active immunization with the β-subunit of hCG coupled to tetanus toxoid (tt) on the gonadotropic activity of hCG was investigated in hamsters implanted with the BeWo strain of human choriocarcinoma. Control immunized hamsters produced hCG from days 1–15 after the lag phase of tumor growth. Peak levels of hCG (>3 μg hCG/ml serum) were recorded on day 5. hCGβ-tt immunization inhibited the increases in ovarian and uterine weights and estrogen (E) and progesterone (P) levels induced by hCG in controls at various points after the beginning of tumor growth. Ovarian and uterine weights did not significantly rise above the peak weights of the normal 4-day estrus cycle between 0900–1100 h until day 10 in tumor-bearing hamsters immunized with hCGβ-tt. In contrast, both ovaries and uteri showed significant increases in weight by day 1 of tumor growth in controls. P increases were completely blocked throughout the 15 days of tumor growth after hCGβ-tt immunization. Likewise, rises in E were suppressed t...

Toxicological Studies of Shale Oils, Some of Their Components, and Commercial Products

Estonian shale oil contains about 25--30% phenols, and their action determines the toxicity of shale oils. The clinical symptoms of intoxication are rather similar, regardless of route of administration. Due to neurotropic action, the coordination of movements is impaired, and clonic and tetanic convulsions, paresis and paralysis of extremities, and narcosis are observed. In subacute and chronic toxicity tests, dysfunction of the central nervous system was found. In long-term (4--6 month) experiments, changes in liver and kidney function were found. Shale oil has gonadotropic activity and causes changes in the sexual cycle as well as diminution of the number of primordial folicles in the ovaries or a decrease in the quantity of normal spermatogonia in testicular germinal epithelium. Shale oils produce local irritation of skin and mucous membranes. Shale oil can induce sensitization of the organism after repeated administration. The results of acute intoxication tests have proved that volatile and nonvolatile phenol fractions, isomeric dimethylphenols, and 5-methylresorcinol, must be characterized as moderately toxic substances; the LD50 ranges from 501 to 1500 mg/kg. The clinical symptoms of acute toxication are similar for all studied phenols (restlessness, unsteadiness, clonic tremor, paresis and paralysis of extremities, and death). In spite of the moderate toxicity of phenols in acute experiments, repeated administration of small doses can cause different changes in the nervous system and internal organs of experimental animals. For all the phenols studied, the maximum allowable concentration in water was limited by their effect on the organoleptic properties of water. The nonactive dose for warm-blooded animals is from 100 to 3000 times the threshold limit value of phenols on the basis of their organoleptic properties. The effect of commercial products of oil shale industry is generally determined by the toxicity of the main components: water-soluble oil shale phenols.

Toxicological studies of shale oils, some of their components, and commercial products.

Estonian shale oil contains about 25--30% phenols, and their action determines the toxicity of shale oils. The clinical symptoms of intoxication are rather similar, regardless of route of administration. Due to neurotropic action, the coordination of movements is impaired, and clonic and tetanic convulsions, paresis and paralysis of extremities, and narcosis are observed. In subacute and chronic toxicity tests, dysfunction of the central nervous system was found. In long-term (4--6 month) experiments, changes in liver and kidney function were found. Shale oil has gonadotropic activity and causes changes in the sexual cycle as well as diminution of the number of primordial folicles in the ovaries or a decrease in the quantity of normal spermatogonia in testicular germinal epithelium. Shale oils produce local irritation of skin and mucous membranes. Shale oil can induce sensitization of the organism after repeated administration. The results of acute intoxication tests have proved that volatile and nonvolatile phenol fractions, isomeric dimethylphenols, and 5-methylresorcinol, must be characterized as moderately toxic substances; the LD50 ranges from 501 to 1500 mg/kg. The clinical symptoms of acute toxication are similar for all studied phenols (restlessness, unsteadiness, clonic tremor, paresis and paralysis of extremities, and death). In spite of the moderate toxicity of phenols in acute experiments, repeated administration of small doses can cause different changes in the nervous system and internal organs of experimental animals. For all the phenols studied, the maximum allowable concentration in water was limited by their effect on the organoleptic properties of water. The nonactive dose for warm-blooded animals is from 100 to 3000 times the threshold limit value of phenols on the basis of their organoleptic properties. The effect of commercial products of oil shale industry is generally determined by the toxicity of the main components: water-soluble oil shale phenols.

The effect of gonadal and thyroidal hormones on the regulation of food intake and adiposity, and on various endocrine glands, in the red-winged blackbird ( Agelaius phoeniceus)

The effects of testosterone propionate (TP), clomiphene citrate (CC), thyroxine (T 4, and propilthiouracil (PTU) on food and water intake, adiposity, and various endocrine glands of male red-winged blackbird were studied. TP induced hyperphagia with obesity, increased prolactin cell population in the pituitary, and supressed the gonadotropic activity. CC had the opposite effects to TP. T 4 induced hyperphagia without obesity, increased somatotrops population in the adenohypophysis, but suppressed thyrotropic and gonadotropic activities. PTU reduced food intake without affecting adiposity and enhanced throtropic activity while supressed the gonadotropic one. All treatments induced enlargement of the adrenal cortex. The relationships among the various effects are discussed.

Activity of Juvenile Hormone Mimics Against the Mediterranean Fruit Fly13

Nine well known juvenoids were tested against all developmental stages of Ceratitis capitata (Wiedemann) to investigate the potential of hormonal methods for its control. Compounds containing aromatic structures were of significant ovicidal activity while open chain compounds were more active in morphogenetic tests. Both types of juvenoids showed similar gonadotropic activity.

Effect of carbidine on the gonads of rats during chronic alcohol poisoning

Experiments on rats showed that carbidine, when injected intramuscularly for 2 weeks in a dose effective for the experimental treatment of alcohol dependence (4 mg/kg), has no gonadotropic action. The drug does not potentiate the adverse after-effects of chronic ethanol poisoning on ovogenesis or spermatogenesis and does not delay the course of repair processes in the gonads after cessation of the ethanol intake. However, carbidine is given during continued consumption of ethanol, further development of the regressive changes in the generative cells of the gonads is observed.

Separation of the gonadotropic activity of crude choriogonadotropin from the inhibitory effect on lymphocyte transformation.

The effect of choriogonadotropin of different purities on the transformation of peripheral human lymphocytes was studied. Various crude hormone batches inhibited lymphocyte transformation in a dose-dependent manner, both in the mixed lymphocyte reaction and in the phytohemagglutinin-induced stimulation. The inhibitory activity, however, was found not to be correlated with the gonadotropic activity of the crude hormone batches (2660-4300 IU/mg). Choriogonadotropin (13 000 IU/mg), which was purified in 3 steps, showed no inhibitory effect except at high doses (greater than 5000 IU/ml final dilution). More detailed investigations provided evidence that in the first step of the choriogonadotropin purification procedure (batch adsorption of crude choriogonadotropin on SP-Sephadex C-50), the inhibitory activity can be enriched in a fraction (Fract. I) which displays a very low gonadotropic activity (less than 500 IU/mg). A further separation of Fract. I was achieved by isoelectric focusing as well as by chromatography on DEAE-Sephadex A-25. By these means, the inhibitory potency could be enriched more than 100-fold. The substances which display inhibition of DNA synthesis in lymphocytes were proven to act in a nontoxic way. A preliminary characterization of the strongly inhibiting substances which show a dose-dependent suppression of lymphocyte transformation by about 99%, showed that this effect is probably exerted via non-dialysable sialoglycoproteins. By a fourth purification step entailing a chromatography of purified choriogonadotropin (13 000 IU/mg) on SP-Sephadex C-50, a highly purified choriogonadotropin (14000 IU/mg) could be obtained which showed no inhibitory effect on lymphocyte transformation (in both mixed lymphocyte reaction and in phytohemagglutinin-induced stimulation) up to a dose of 43 000 IU/ml. The components which were removed from choriogonadotropin in this step seem to be immunologically identical with the strongly inhibiting substances isolated by isoelectric focusing. These investigations demonstrate that biologically active, highly purified choriogonadotropin is unable to inhibit lymphocyte transformation. The inhibitory activity of crude hormone can be enriched in choriogonadotropin-free fractions. Therefore, it is concluded that the inhibitory activity of crude hormone is not a property of choriogonadotropin itself.

A Chemical Study of Some Biologically Active Pineal Fractions

Publisher Summary Accumulated evidence indicates that the pineal gland is a highly active organ, synthesizing a number of compounds. A variety of experiments have demonstrated inhibiting activity on the reproductive system and it is postulated that the pineal secretes substances which may exert their effects on the hypothalamic-hypophyseal-gonadal axis. This chapter presents experiments, which were carried out to purify and identify compounds present in different pineal fractions, showing an influence on the gonadotropic activity. Difficulty in this research will always be that pteridines and especially the reduced forms, are very light-sensitive and therefore unstable; synthetic pteridines in a pure form are commercially hardly available.

Effects of an Essential Fatty Acid Deficiency, Pair-Feeding and Level of Dietary Corn Oil on the Hypothalamic-Pituitary-Gonadal Axis and Other Physiological Parameters in the Male Chicken

Two studies were conducted to observe the effects of an essential fatty acid (EFA) deficiency, added dietary corn oil and pair-feeding on growth, reproduction and other physiological parameters in the mature cockerel. A purified, linoleic acid (LA)-deficient diet (0.01% LA), or additions of 5% (3.01% LA) or 15% (9.04% LA) corn oil, were fed ad libitum from hatching through 24 weeks of age. Reductions in growth, feed consumption, and comb, and testes size, incomplete spermatogenesis, increased tissue eicosatrienoic acid (20: 3 omega 9) and changes in weights of selected internal organs were observed in deficient cockerels. Total pituitary gonadotropic activity was measured by two bioassay procedures and blood luteinizing hormone was measured by radioimmunoassay. By maturity both of these parameters were significantly reduced in deficient chickens. When these chickens were fed diets with 5% or 15% corn oil under pair-feeding or ad libitum conditions from 20 to 24 weeks, the reduced growth, comb and testes size and gonadotropin metabolism appeared to be caused by depressions in appetite and energy intake rather than EFA per se. The degenerate testicular histology of the 20-week old deficient cockerels, while responding fully to the ad libitum intake of the diets containing corn oil, showed only partial rehabilitation of spermatogenesis when diets with either 5% or 15% corn oil were pair-fed. In general, increasing the level of dietary fat from 5% to 15% did not cause many physiological changes.

Effect of Testosterone on the Cock Pituitary <i>in vitro</i> Leading to the Release of Gonadotropins

Hemisected pituitaries of cods were incubated in vitro at 41°C for 3hr with and without testosterone. progesterone, or estradiol-17β (1 and 10ng/ml), and media were assayed for the gonadotropic activity by using a bioassay method based on 32P-uptake by chick testes. The media in which the pituitary halves were incubated with testosterone (10ng/ml) showed a greater gonadotropic activity than those in which the other pituitary halves were incubated without testosterone. Incubations with progesterone or estradiol-17β did not result in a change in the gonadotropic activity of the media. When pituitaries were divided into cephalic and caudal lobes, and each lobe was hemisected and incubated in the same way, the incubation of the cephalic lobes with testosterone (5 and 10ng/ml) resulted in the increase in the gonadotropic activity of the media, while the incubation of the caudal lobes did not result in the increase. Synthetic GnRH (250 and 500ng/ml) caused the increase in the gonadotropic activity of the media in both incubations of the cephalic lobes and of the caudal lobes. The results suggest that testosterone acts on the pituitary and leads to the release of gonadotropins, and that the responsiveness of the pituitary to testosterone differs between the cephalic and caudal lobes.

Endocrinology of Polychaete Reproduction and Sexual Development

Abstract The endocrinology of Nereids, though the most thoroughly investigated, cannot in its hormonal pattern be generalized for all Polychaetes. Gonadotropic principles seem to be more widespread among the species of this class. Considering the diversity of results, it is almost impossible to generalize the present knowledge on polychaete endocrinology. However, there seem to exist at least three different situations: (a) the nereid inhibitory system in monotelic epitokous species, where caudal regeneration depends on brain hormone; (b) a gonadotropic activity of brain hormone(s) in polytelic species, where caudal regeneration does not depend on brain hormone, and (c) the syllid inhibitory system which simultaneously seems to govern sexual differentiation.

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.

Effect of Changing Photoperiods on the Diurnal Rhythm of Pituitary Gonadotropic Activity of Mature Male Japanese Quail

Male Japanese quail were raised under 14-hr (5:00-19:00) light per day for 4 months from the day of hatch, and their gonadotropic activities of the anterior lobes of pituitary at various times during a 24-hr period were measured using a bioassay method based on 32P-uptake by chick testes. A peak of the gonadotropic activity was found at the end of light period. When the time of onset of light was shifted from 5:00 to 17:00 and the birds were kept for 2 weeks, the peak shifted to a time close to the end of the new light period. When the length of the light period was reduced to 8 hours and the birds were kept for 16 weeks, the peak disappeared.

ニワトリの下垂体前葉の前部腺体ならびに後部腺体における性腺刺激ホルモン力価の日内変動

14時間照明10時間暗黒の明暗周期下においた白色レグホーン種の未成熟雄鶏(5週齢,7週齢および10週齢),未成熟雌鶏(5週齢および10週齢),成熟雄鶏(18か月齢),および成熟雌鶏(産卵鶏:14か月齢)を1日のうちのいろいろな時刻に殺して下垂体前葉を採取し,その前部腺体および後部腺体の性腺刺激ホルモン(GTH)力価を雛精巣32P取込法によって測定した.未成熟雄鶏および未成熟雌鶏においては前部腺体のGTH力価には日内変動は認められなかったが,後部腺体には日内変動が認められ,5週齢時においては14時(照明開始9時間後)にピークが見出され,7週齢または10週齢においては11時(照明開始6時間後)にピークが見出された.成熟雄鶏および成熟雌鶏においては後部腺体のみならず前部腺体においても日内変動が認められた.すなわち,成熟雄鶏においては前部腺体にも後部腺体にもともに11時をピークとする1峰性の変動が見出された.また成熟雌鶏においては前部腺体において11時のほかに0-3時(排卵7-11時間前)にもピークを示す2峰性の変動が見出されたが,後部腺体においては前部腺体における変動とやや異なる変動が見出された.

Diurnal Change in the Pituitary Gonadotropic Activity in Immature Cockerels

Diurnal Change in the Pituitary Gonadotropic Activity in Immature Cockerels

Diurnal Change in the Pituitary Gonadotropic Activity in Cocks and Hens

Diurnal Change in the Pituitary Gonadotropic Activity in Cocks and Hens