THE EFFECTS OF TREATMENT WITH GONADOTROPHINS OR WITH OESTROGEN ON THE THYROID GLAND OF THE IMMATURE RAT

1966 ◽  
Vol 35 (3) ◽  
pp. 263-270 ◽  
Author(s):  
K. BROWN-GRANT
Keyword(s):  
Thyroid Gland ◽  
Hormone Secretion ◽  
Thyroid Stimulating Hormone ◽  
Female Rats ◽  
Male Rats ◽  
Luteinizing Hormone Secretion ◽  
Immature Female ◽  
Immature Rat ◽  
Tsh Secretion ◽  
Pregnant Mare Serum Gonadotrophin

SUMMARY The uptake of 131I by the thyroid gland increased 72 hr. after the injection of pregnant mare serum gonadotrophin (PMS) into immature female rats whether ovulation occurred or not. PMS failed to produce this effect in male rats but oestrogen administration increased 131I uptake in both male and female immature rats, suggesting that oestrogen was responsible for the effect of PMS in females. Both PMS and oestrogen may increase the uptake of radioactive phosphate by the thyroid of female but not male rats; oestrogen may stimulate thyroid-stimulating hormone (TSH) secretion in immature female rats. These effects of oestrogen in the female made it impossible to determine whether the 'ovulatory surge' in luteinizing hormone secretion in PMS-treated rats was associated with an increased secretion of TSH or not.

EFFECT OF SYNTHETIC THYROTROPHIN RELEASING FACTOR ON PROLACTIN AND LUTEINIZING HORMONE SECRETION IN MALE AND FEMALE RATS DURING VARIOUS REPRODUCTIVE STATES

1975 ◽  
Vol 67 (3) ◽  
pp. 425-430 ◽  
Author(s):  
R. P. DEIS ◽  
NIA ALONSO
Keyword(s):  
Hormone Secretion ◽  
Female Rats ◽  
Male Rats ◽  
Serum Prolactin ◽  
Serum Prolactin Level ◽  
Luteinizing Hormone Secretion ◽  
Male And Female Rats ◽  
Serum Lh ◽  
The Mean ◽  
Lh Secretion

SUMMARY The effect of synthetic thyrotrophin releasing factor (TRF) on serum prolactin and LH concentrations was determined by radioimmunoassay in male, cyclic and pseudopregnant female rats. A solution of TRF (0·1, 0·25, 0·5 and 1 μg/rat) was injected i.v. at 17.00 h into rats pretreated with sodium pentobarbitone at 13.00 h. A group of male rats was also treated with TRF at 11.00 h after pretreatment with sodium pentobarbitone at 07.00 h. Fifteen minutes after TRF administration, blood samples were obtained by heart puncture. Doses of 0·25, 0·5 and 1 μg TRF significantly increased the serum prolactin concentration in pro-oestrous rats. The mean serum prolactin level after the injection of 0·5 and 1 μg into oestrous rats and 0·5 μg TRF into dioestrous day 2 rats, was significantly greater than the control values. Injection of TRF on day 1 of dioestrus had no effect. Serum LH concentration was not significantly modified by the various doses of TRF administered. On day 3 of pseudopregnancy a significant increase of serum prolactin values was obtained with 0·5 and 1 μg TRF. On day 7 of pseudopregnancy a dose of 0·5 μg produced the same effect, but on day 10 of pseudopregnancy only 1 μg TRF significantly increased serum prolactin levels when compared with the control rats. In male rats serum prolactin concentration was significantly greater than the control values after TRF treatment either in the morning or the afternoon. The response was similar to that obtained in pro-oestrous rats. The results suggest that the ability of synthetic TRF to stimulate prolactin release exists in both female and male rats and that TRF does not affect LH secretion.

DIE BEDEUTUNG VON GONADEN UND HYPOPHYSE FÜR DIE WIRKUNG GONADOTROPER HORMONE AUF DIE SCHILDDRÜSENFUNKTION

1960 ◽  
Vol XXXIV (II) ◽  
pp. 176-188 ◽  
Author(s):  
A. Hasselblatt ◽  
Ch. Ratabongs
Keyword(s):  
Thyroid Gland ◽  
Pituitary Gland ◽  
Thyroid Function ◽  
Functional Relationship ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Female Rats ◽  
Male Rats ◽  
Hormonal Secretion ◽  
Pregnant Mare Serum Gonadotrophin

ABSTRACT The effect of pregnant mare serum gonadotrophin (PMS) and human chorionic gonadotrophin (HCG) on the thyroid gland of normal, of gonadectomized and of hypophysectomized infantile rats has been studied. Gonadotrophin treatment stimulated the thyroid of normal and hypophysectomized female rats. A corresponding effect was not observed in gonadectomized female or in normal and gonadectomized male rats. These results show that the gonadotrophic hormones stimulate thyroid function indirectly by increasing the hormonal secretion of the ovaries. An intimate functional relationship between the ovaries and the thyroid gland was thus demonstrated. As the stimulating effect of gonadotrophin treatment was also present in hypophysectomized female rats, it was concluded that the oestrogens act directly on the thyroid gland. Their thyrotrophic action is not mediated by the pituitary gland.

Effects of galanin-like peptide on luteinizing hormone secretion in the rat: sexually dimorphic responses and enhanced sensitivity at male puberty

2006 ◽  
Vol 291 (6) ◽  
pp. E1281-E1289 ◽  
Author(s):  
J. M. Castellano ◽  
V. M. Navarro ◽  
R. Fernández-Fernández ◽  
J. Roa ◽  
E. Vigo ◽  
...  
Keyword(s):  
Luteinizing Hormone ◽  
Hormone Secretion ◽  
Metabolic Stress ◽  
Female Rats ◽  
Metabolic Status ◽  
Male Rats ◽  
Intracerebral Injection ◽  
Luteinizing Hormone Secretion ◽  
Male Puberty ◽  
Lh Secretion

Reproductive function is exquisitely sensitive to adequacy of nutrition and fuel reserves, through mechanisms that are yet to be completely elucidated. Galanin-like peptide (GALP) has recently emerged as another neuropeptide link that couples reproduction and metabolism. However, although the effects of GALP on luteinizing hormone (LH) secretion have been studied, no systematic investigation on how these responses might differ along sexual maturation and between sexes has been reported. Moreover, the influence of metabolic status and potential interplay with other relevant neurotransmitters controlling LH secretion remain ill defined. These facets of GALP physiology were addressed herein. Intracerebral injection of GALP to male rats induced a dose-dependent increase in serum LH levels, the magnitude of which was significantly greater in pubertal than in adult males. In contrast, negligible LH responses to GALP were detected in pubertal or adult female rats at diestrus. Neonatal androgen treatment to females failed to “masculinize” the pattern of LH response to GALP. In addition, metabolic stress by short-term fasting did not prevent but rather amplified LH responses to GALP in pubertal males, whereas these responses were abrogated by pharmacological inhibition of nitric oxide synthesis. We conclude that the ability of GALP to evoke LH secretion is sexually differentiated, with maximal responses at male puberty, a phenomenon which was not reverted by manipulation of sex steroid milieu during the critical neonatal period and was sensitive to metabolic stress. This state of LH hyperresponsiveness may prove relevant for the mechanisms relaying metabolic status to the reproductive axis in male puberty.

THE EFFECT OF CHLORMADINONE ON THE RESPONSE OF THE OVARIES AND UTERUS OF THE IMMATURE RAT TO GONADOTROPHIC STIMULATION

1964 ◽  
Vol 30 (2) ◽  
pp. 235-245 ◽  
Author(s):  
M. J. K. HARPER
Keyword(s):  
Ovarian Response ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Female Rats ◽  
Corpora Lutea ◽  
Immature Female ◽  
Immature Rat ◽  
Orally Active ◽  
Pregnant Mare Serum Gonadotrophin ◽  
Intact Rats

SUMMARY The effects of chlormadinone (6-chloro-Δ6-17α-acetoxyprogesterone), an orally active progestational agent without significant oestrogenic activity, on the response of the ovaries of intact and hypophysectomized immature female rats to exogenous gonadotrophin have been examined. Administration of the steroid whether starting on the same day as, or 4 days before treatment with gonadotrophin, did not depress the ovarian response in intact rats. In hypophysectomized animals, pretreated with the progestagen, the ovarian response to gonadotrophin was depressed. In intact rats, treatment with the steroid and pregnant mare serum gonadotrophin (PMSG) resulted in ovulation, whereas in similar animals given PMSG alone no corpora lutea were found. Corpora lutea were seen in all groups given PMSG and human chorionic gonadotrophin (HCG) but ovulation occurred earlier when, in addition, treatment with the steroid was included. In only one experiment with intact rats did administration of the steroid alone cause a significant increase in uterine weight compared with controls. In neither experiment on hypophysectomized animals did such an increase occur, and significant decreases were recorded.

scholarly journals Neonatal stimulation of the thyroid gland with iodine or suppression during adolescence with triiodothyronine changes the prevalence of autoimmune thyroiditis in BB rats

2004 ◽  
pp. 375-382 ◽  
Author(s):  
ML Hartoft-Nielsen ◽  
AK Rasmussen ◽  
A Kaas ◽  
U Feldt-Rasmussen ◽  
K Buschard
Keyword(s):  
Thyroid Gland ◽  
Autoimmune Thyroiditis ◽  
Lymphocytic Infiltration ◽  
Thyroid Stimulating Hormone ◽  
Female Rats ◽  
Male Rats ◽  
Bb Rats ◽  
Neonatal Stimulation ◽  
Stimulation Of

OBJECTIVE: Changes in the functional state of beta cells by neonatal stimulation or adolescent suppression have reduced the incidence of type 1 diabetes mellitus in animal models. The aim of this study was to evaluate the effect of manipulation of the activity of the thyroid gland by neonatal stimulation or by adolescent suppression on the prevalence of spontaneous autoimmune thyroiditis (AIT) in rats. METHODS: Bio-Breeding/Worcester (BB) rats were treated neonatally with sodium iodine (NaI) or thyroid stimulating hormone (TSH), or during adolescence by triiodothyronine (T(3)), and the lymphocytic infiltration in the thyroid gland was evaluated. RESULTS: Neonatal treatment with NaI decreased the prevalence of AIT to 32+/-9% compared with 66+/-5% in the controls (P<0.002), mainly caused by a reduction among the female rats (13+/-9% vs 52+/-8%, P<0.006). TSH had no effect. Post neonatal suppression of the thyroid gland by T(3) had a biphasic response. Early in adolescence the overall prevalence was 14+/-7% compared with 66+/-5% in the controls (P<10(-5)); for female rats AIT was prevented (0+/-0%) compared with 52+/-8% in the controls (P<0.0003) and in male rats the values were 29+/-13% compared with 80+/-6% in the controls (P<0.001). Treatment with T(3) later in adolescence increased the overall prevalence to 81+/-7% compared with 66+/-5% in the controls (not significant). For female rats the prevalence increased to 78+/-9% compared with 52+/-8% in the controls (P=0.04). The degree of thyroiditis among the affected animals was similar in all groups. CONCLUSION: Neonatal stimulation of the thyroid gland by iodine or early adolescent suppression by T(3) reduced the prevalence of AIT whereas T(3) given later increased the prevalence of thyroiditis in rats. Thyroid activity at various ages seems to be of importance for the development of autoimmune thyroiditis.

OVULATION INDUCED BY PREGNANT MARE SERUM GONADOTROPHIN IN THE IMMATURE RAT TREATED NEONATALLY WITH A LOW OR A HIGH DOSE OF ANDROGEN

1972 ◽  
Vol 55 (3) ◽  
pp. 533-541 ◽  
Author(s):  
J. Th. J. UILENBROEK ◽  
J. J. van der WERFF ten BOSCH
Keyword(s):  
Testosterone Propionate ◽  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Female Rats ◽  
High Dose ◽  
Immature Female ◽  
Immature Rat ◽  
Progesterone Treatment ◽  
Combined Administration ◽  
Pregnant Mare Serum Gonadotrophin

SUMMARY Ovulation-inducing effects of pregnant mare serum gonadotrophin (PMSG) were studied in immature female rats treated on day 5 (day 1 = day of birth) with oil or with 5 or 1250 μg testosterone propionate (TP). The response of rats treated with 1250 μg TP was negligible regardless of the age of the animals and of the dose of PMSG. The response of rats treated with 5 μg TP to PMSG alone was low (36% of rats, with 2·6 ova/ovulating rat), but could be improved by progesterone administration 2 days after PMSG injection (91% of rats, with 14·5 ova/ovulating rat). At every age and dose of PMSG tested the response of animals treated with 5 μg TP to combined PMSG and progesterone treatment was less than that of control animals. It is concluded that neonatal TP treatment diminishes the release of endogenous ovulating hormone subsequent to PMSG injection. This effect is dependent on the dose of TP used, but already demonstrable in animals treated with 5 μg TP on day 5, which would have been cyclic and fertile after puberty. Only for the animals treated with 1250 μg TP could a decreased sensitivity of the ovaries to combined administration of PMSG and human chorionic gonadotrophin be demonstrated.

scholarly journals Dietary nutrients implicated in the etiopathogenesis of human and animal diseases

2017 ◽  
Author(s):  
◽  
Sarah E. Hooper
Keyword(s):  
Animal Model ◽  
Thyroid Gland ◽  
Strong Support ◽  
Nodular Goiter ◽  
Thyroid Stimulating Hormone ◽  
Activity Level ◽  
Female Rats ◽  
Male Rats ◽  
Future Research ◽  
Dietary Nutrients

Hyperthyroidism is a spontaneous disease that results in an abnormal elevation of circulating concentrations of one or more thyroid hormones. Despite being the most commonly diagnosed endocrine disorder of domestic cats, the etiopathogenesis remains unknown. My dissertation research sought to investigate whether the dietary nutrients selenium, water, and taurine cause an overstimulation of the thyroid gland and alter the function of the hypothalamic-pituitary-thyroid axis. Because feline hyperthyroidism is clinically and pathologically similar to toxic nodular goiter or Plummer's disease, one of the most common types of hyperthyroidism in humans, I sought to determine if cats are a better animal model than rats for studying dietary causes of hyperthyroidism. To my knowledge, this is the first project to conduct simultaneous animal studies where two species are assessed for suitability as animal models for a human disease and concurrently conduct hypothesis-driven research on potential dietary etiologies of a disease that affects both the domestic feline population and humans. This unique experimental design provided strong support that cats are a better animal model of toxic multinodular goiter, because we were able to establish that cats have an individual set-point for thyroid-stimulating hormone (TSH) which similar to humans. Additionally, we showed that there was a positive correlation with taurine consumption and circulating triiodothyronine (T3) in female rats but not male rats. Women are five to eight times more likely to suffer from a thyroid disease. Our findings indicate future research is needed to determine if supplemental taurine and consumption of high taurine diets predisposes women to thyroid gland disorders. Furthermore, in cats, consumption of water significantly altered the production of T3 and caused a 20% increase in activity level. Because consumption of canned cat food has been the only consistently identified risk factor in epidemiological studies, our results indicate future studies should focus on the relationship between water consumption and feline thyroid physiology.

Changes in the characteristics of pulsatile luteinizing hormone secretion during the oestrous cycle and after ovariectomy and oestrogen treatment in female rats

1982 ◽  
Vol 94 (2) ◽  
pp. 177-182 ◽  
Author(s):  
Takashi Higuchi ◽  
Masazumi Kawakami
Keyword(s):  
Hormone Secretion ◽  
Pulse Amplitude ◽  
Pulse Frequency ◽  
Oestrous Cycle ◽  
Female Rats ◽  
Ovariectomized Rats ◽  
Luteinizing Hormone Secretion ◽  
Oestrogen Treatment ◽  
Serum Lh ◽  
Lh Release

Changes in the characteristics of LH secretory pulses in female rats were determined in different hormonal conditions; during the oestrous cycle and after ovariectomy and oestrogen treatment. The frequency and amplitude of the LH pulses were stable during the oestrous cycle except at oestrus when a pattern could not be discerned because of low LH concentrations. These were significantly lower than those measured during other stages of the cycle. Mean LH concentrations and LH pulse amplitudes increased with time up to 30 days after ovariectomy. The frequency of the LH pulse was unchanged 4 days after ovariectomy when mean LH levels had already increased. The frequency increased 10 days after ovariectomy and then remained stable in spite of a further increase in mean serum LH concentrations. Oestradiol-17β injected into ovariectomized rats caused a decrease in LH pulse amplitude but no change in pulse frequency. One day after treatment with oestradiol benzoate no LH pulse was detectable, probably because the amplitude was too small. A generator of pulsatile LH release is postulated and an oestrogen effect on its function is discussed.

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