EFFECT OF HYPOPHYSECTOMY ON BINDING OF HUMAN CHORIONIC GONADOTROPHIN TO IMMATURE AND ADULT RAT OVARIES

1977 ◽  
Vol 75 (2) ◽  
pp. 271-276 ◽  
Author(s):  
J. W. SIEBERS ◽  
W. ENGEL
Keyword(s):  
Binding Capacity ◽  
Ovarian Tissue ◽  
Binding Activity ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Scatchard Analysis ◽  
Adult Rats ◽  
Adult Rat ◽  
Immature Rats ◽  
Pituitary Ablation

The binding of 125I-labelled human chorionic gonadotrophin (HCG) to ovarian tissue was studied in hypophysectomized immature and adult rats. The ability of the ovaries of adult rats to bind HCG was markedly reduced within 3 days of hypophysectomy and remained low for at least 20 days. The extent of the reduction depended on the stage of the oestrous cycle at which hypophysectomy was performed. The highest loss of HCG binding capacity was seen in rats hypophysectomized at dioestrus II, while rats hypophysectomized at the oestrous stage exhibited similar HCG binding to control rats at the same stage of the cycle. Scatchard analysis indicated that the reduction in the capacity of the ovary to bind HCG after hypophysectomy was caused by the loss of specific receptors and not by a decrease in binding affinity. In contrast to adult rats, in immature rats the HCG binding capacity of the ovaries did not change during the 3 days after hypophysectomy, but after this a slow decline took place. Twenty days after pituitary ablation, almost identical values for binding of HCG were found in immature and adult rats. Since hypophysectomy in adult rats causes a rapid regression of large follicles, our results indicate that the remaining HCG binding activity arises largely from small follicles which are known to be unaltered by the deprivation of hypophysial hormones. This assumption is supported by our observation that in the ovaries of 25-day-old immature rats, which lack large follicles, only a slow decrease in the ability of the ovaries to bind HCG occurs in the 20 days after the operation.

BINDING OF HUMAN CHORIONIC GONADOTROPHIN BY RAT TESTIS: EFFECT OF SEXUAL MATURATION, CRYPTORCHIDISM AND HYPOPHYSECTOMY

1975 ◽  
Vol 64 (1) ◽  
pp. 59-66 ◽  
Author(s):  
JOACHIM FROWEIN ◽  
WOLFGANG ENGEL
Keyword(s):  
Dissociation Constant ◽  
Sexual Maturation ◽  
Leydig Cells ◽  
Binding Capacity ◽  
Specific Binding ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Scatchard Analysis ◽  
Rat Testis ◽  
Relative Binding

SUMMARY The specific binding of 125I-labelled human chorionic gonadotrophin (HCG) by rat testicular homogenate as compared with isolated Leydig cells differs with respect to total binding capacity but not to the dissociation constant (KD) as revealed by Scatchard analysis. The maximal binding capacity for [125I]HCG of crude testicular homogenate was 95 ng/g rat testis. Hypophysectomy causes a decline in binding capacity within the first three days but on the 20th and 30th day after hypophysectomy the relative binding capacity no longer differs from that of controls. Binding capacity is enhanced in cryptorchid testes relative to normal, and increases during sexual maturation to a peak shortly before puberty.

STIMULATION BY β2-ADRENERGIC RECEPTORS OF THE PRODUCTION OF CYCLIC AMP AND PROGESTERONE IN RAT OVARIAN TISSUE

1980 ◽  
Vol 87 (1) ◽  
pp. 123-129 ◽  
Author(s):  
ALBERT RATNER ◽  
G. K. WEISS ◽  
CAROLYN R. SANBORN
Keyword(s):  
Cyclic Amp ◽  
Adrenergic Receptors ◽  
Ovarian Tissue ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Adrenergic Stimulation ◽  
Immature Rats ◽  
Luteal Tissue ◽  
Pregnant Mare Serum Gonadotrophin ◽  
Stimulation Of

Ovarian tissue from immature rats treated with pregnant mare serum gonadotrophin (PMSG) or PMSG and human chorionic gonadotrophin was incubated in Medium 199. Stimulation of the formation of cyclic AMP in follicular and luteal tissue by terbutaline (10−5 mol/l), a selective β2-agonist, was blocked by butoxamine (10−5 mol/l), a selective β2-antagonist, whereas practolol (10−5 mol/l), a selective β1-antagonist, was ineffective. Propranolol (10−5 mol/l), a non-selective β-antagonist, butoxamine nor practolol affected the increase in cyclic AMP promoted by the addition of 1 μg LH. Stimulation of the production of progesterone in both follicular and luteal tissue by terbutaline was blocked by butoxamine, but not by practolol. These findings indicated that β-adrenergic stimulation of ovarian cyclic AMP and progesterone is mediated by β2-adrenergic receptors.

OVULATION IN ADULT RATS AFTER TREATMENT WITH PREGNANT MARE SERUM GONADOTROPHIN DURING OESTRUS

1971 ◽  
Vol 68 (1) ◽  
pp. 41-49 ◽  
Author(s):  
R. Welschen ◽  
M. Rutte
Keyword(s):  
Dose Level ◽  
Size Range ◽  
Standard Procedure ◽  
Indirect Evidence ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
List Type ◽  
Adult Rats ◽  
Adult Rat ◽  
Pregnant Mare Serum Gonadotrophin

ABSTRACT Treatment of the adult rat with pregnant mare serum gonadotrophin (PMS) followed by human chorionic gonadotrophin (HCG) is the standard procedure for inducing superovulation. Experiments were performed on rats with a 5 day cycle to determine why treatment with PMS only does not produce superovulation. In untreated animals all follicles in a range of [2267] 55 × 106 μm3 take part in ovulation. Similarly, in precocious ovulation induced by HCG in otherwise untreated animals, all follicles in this size range produce ovulations. After the injection of 5 IU of PMS into rats during oestrus the number of follicles in the size range of [2267] 55 × 106 μm3 is doubled, but only half of them take part in spontaneous ovulation, which occurs one day earlier than in untreated animals. An additional ovulating stimulus by means of treatment with HCG causes no increase in the number of ovulations. Data from hypophysectomized animals receiving HCG indicate that the ovulatory release of luteinizing hormone (LH) is not subnormal following treatment with 5 IU of PMS. After the administration of 10–35 IU PMS in oestrus, spontaneous ovulation does not occur. Data on hypophysectomized animals receiving HCG indicate that at this dose level of PMS, the ovulatory release of LH is subnormal. Indirect evidence suggests that this is due to high oestrogen levels in the blood, blocking the ovulatory release of LH. After 50–80 IU of PMS spontaneous ovulation of a small number of ova occurs on day 3. The ovulatory release of LH, estimated as in the previous experiments, is not distinctly subnormal. Therefore at this dose level of PMS a diminished responsiveness of the ovaries is responsible for the subnormal number of ovulations.

Effects of hypophysectomy and subsequent FSH and testosterone treatment on inhibin production by adult rat testes

1985 ◽  
Vol 105 (1) ◽  
pp. 1-6 ◽  
Author(s):  
C. L. Au ◽  
D. M. Robertson ◽  
D. M. de Kretser
Keyword(s):  
Seminiferous Tubule ◽  
Hormonal Control ◽  
Human Chorionic Gonadotrophin ◽  
Experimental Conditions ◽  
Adult Rats ◽  
Adult Rat ◽  
Fluid Production ◽  
Tubule Fluid

ABSTRACT The hormonal control of inhibin production by adult rat testes was investigated using an in-vitro inhibin bioassay validated for the measurement of inhibin activity in charcoal-treated rat testicular extracts. The effect of hypophysectomy examined at 16 h, 3, 7 and 42 days after surgery showed a decrease in testicular inhibin content and seminiferous tubule fluid production by 7 days and a decrease in inhibin production by 42 days. Serum FSH and LH were suppressed 3 days after surgery. In 30-day chronically hypophysectomized adult rats treated for 3 days with twice daily s.c. injections of (a) human FSH (hFSH, 22 i.u./rat per day), (b) testosterone (5 mg/rat per day), (c) hFSH + testosterone (same doses as a and b), or (d) human chorionic gonadotrophin (hCG, 12 i.u./rat per day), hFSH or hFSH and testosterone stimulated an increase in testicular inhibin content but not in inhibin production or tubule fluid production. Testosterone and hCG had no effect on these parameters. It is concluded that in vivo, FSH alone stimulates an increase in testicular inhibin content. The failure to observe an increase in inhibin production in vivo is attributed to the suppression of seminiferous tubule fluid production under the same experimental conditions. J. Endocr. (1985) 105, 1–6

CONCENTRATIONS OF CYCLIC AMP IN RABBIT OVARIAN TISSUE DURING THE PREOVULATORY PERIOD AND PSEUDOPREGNANCY AFTER INDUCTION OF OVULATION BY ADMINISTRATION OF HUMAN CHORIONIC GONADOTROPHIN

1975 ◽  
Vol 65 (1) ◽  
pp. 73-82 ◽  
Author(s):  
A. K. GOFF ◽  
PATRICIA W. MAJOR
Keyword(s):  
Cyclic Amp ◽  
Dose Response ◽  
Ovarian Tissue ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Corpora Lutea ◽  
Response Relationship ◽  
Dose Response Relationship ◽  
Induction Of Ovulation ◽  
Relationship Of

SUMMARY Concentrations of cyclic AMP were measured in rabbit ovaries at various times after injection of an ovulatory dose of human chorionic gonadotrophin (HCG). A biphasic increase in cyclic AMP concentration occurred during the preovulatory period, with peaks 30 min and 3–4 h after HCG injection. Concentrations of cyclic AMP had returned to those observed in ovaries of control oestrous animals before the onset of ovulation 10–12 h after administration of HCG, and remained low throughout the period of pseudopregnancy. Concentrations of cyclic AMP in the newly formed and developing corpora lutea were similar to the concentrations observed in the remainder of the tissue during this period. No significant increase in cyclic AMP concentration was observed 7–9 days after initiation of ovulation. Concentrations of ATP were also investigated during the preovulatory period. The dose– response relationship of HCG to cyclic AMP production in oestrous rabbit ovaries was investigated.

THE SENSITIVITY OF ADRENALECTOMIZED RATS TO GONADOTROPHINS

1954 ◽  
Vol 11 (4) ◽  
pp. 359-376 ◽  
Author(s):  
ANITA M. MANDL
Keyword(s):  
Chorionic Gonadotrophin ◽  
Female Rats ◽  
Corpora Lutea ◽  
Surgical Trauma ◽  
Normal Reaction ◽  
Normal Response ◽  
Immature Female ◽  
Adult Rats ◽  
Immature Rats ◽  
Adrenalectomized Rats

SUMMARY The sensitivity of adrenalectomized, control-operated and unoperated rats to pregnant mare serum (PMS) and chorionic gonadotrophin (CG) has been studied. A total of 638 mature and immature female rats was used. The ovaries of adrenalectomized rats were found to contain fewer large follicles and corpora lutea than those of control-operated litter-mates, and the slight ovarian hypertrophy which occurs after surgical trauma was found to be due to an increase in the number of Graafian follicles and corpora lutea. Further experiment showed that, as judged by the weight of the ovaries, adrenalectomy reduces the ovarian reaction to injected PMS (10 i.u./day) in both adult and immature rats. Replacement therapy with DCA (1 mg/day) failed to re-establish the normal response in adults. Treatment with cortisone (1 mg/day) restored the normal reaction in both adult and immature adrenalectomized rats. Adrenalectomized adult rats responded to injected CG (10 i.u./day) as vigorously as their operated and unoperated litter-mates. On the other hand, immature adrenalectomized animals did not respond fully to CG. Treatment with cortisone again fully restored the normal reaction.

THE EFFECT OF GONADOTROPHIC HORMONES ON THE HYPOPHYSIS OF THE RAT

1962 ◽  
Vol 41 (1) ◽  
pp. 31-34 ◽  
Author(s):  
F. E. Szontágh ◽  
S. Uhlarik ◽  
A. Jakobovits
Keyword(s):  
Anterior Lobe ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Moderate Increase ◽  
Adult Rats ◽  
Ovariectomized Adult Rats

ABSTRACT The weight of the hypophysis and the ratio of the PAS-positive to PAS-negative cells in the anterior lobe of intact and ovariectomized adult rats increased significantly following treatment with serum gonadotrophin (PMS). After the administration of human chorionic gonadotrophin (HCG) a slight decrease of the hypophyseal weight and a moderate increase of the number of PAS-positive cells was observed in both intact and spayed groups of animals. Both gonadotrophic substances failed to inhibit the appearance of castration cells in the hypophysis.

BINDING OF LUTEINIZING HORMONE AND HUMAN CHORIONIC GONADOTROPHIN TO OVARIAN CELLS AND ACTIVATION OF ADENYLATE CYCLASE

1974 ◽  
Vol 61 (2) ◽  
pp. 179-191 ◽  
Author(s):  
Y. KOCH ◽  
U. ZOR ◽  
PRAKONG CHOBSIENG ◽  
S. A. LAMPRECHT ◽  
S. POMERANTZ ◽  
...  
Keyword(s):  
Luteinizing Hormone ◽  
Adenylate Cyclase ◽  
Specific Binding ◽  
Ovarian Tissue ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Target Tissue ◽  
Ovarian Cells ◽  
Receptor Sites ◽  
Effect Binding

SUMMARY The binding of 125I-labelled ovine luteinizing hormone (OLH) and human chorionic gonadotrophin (HCG) to unbroken cells or homogenates from rat and bovine ovaries was studied in relation to the hormonal activation of adenylate cyclase. Both hormones are preferentially bound to ovarian tissue (luteal as well as follicular), while adrenal, kidney and liver showed no specific binding. The bound HCG was associated chiefly with the fraction of the homogenate sedimenting at 1000 g. Addition of excess unlabelled hormone (HCG, OLH) together with the corresponding or heterologous 125I-labelled hormone reduced the radioactivity bound to the tissue by 70–90%; rat LH also competed with OLH and HCG for binding sites, but follicle-stimulating hormone, prolactin, growth hormone, adrenocorticotrophin or glucagon were without effect. Binding could be dissociated from activation of adenylate cyclase by a two-stage incubation: at 4 °C rat ovarian slices bound the labelled hormones, though binding efficiency was reduced to about 20%, but no stimulation of the enzyme was observed. Reincubation of these slices, after washing, at 37 °C in hormone-free medium resulted in maximal activation of adenylate cyclase. Addition of homologous antibodies before the second incubation step abolished the effect of OLH but not that of HCG on the activation of the enzyme. Similarly, addition of homologous antibodies or of excess unlabelled hormone caused dissociation of bound 125I-labelled OLH but not of 125I-labelled HCG from receptor sites. It is concluded that (i) HCG, OLH and rat LH are bound to the same receptor on ovarian cells, but binding of OLH to the receptor is more labile than that of HCG; (ii) the receptor appears to be located on the plasma membrane, since it was largely associated with the 1000 g pellet and since bound OLH remained accessible to antibody; (iii) activation of adenylate cyclase requires the continued occupation of the binding site by the hormone, but occupation of only a fraction of the receptor sites by hormone is adequate to induce maximal production of cyclic AMP by the target tissue.

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