THE EFFECT OF GONADECTOMY ON THE RESPONSE OF THE PITUITARY I. C. S. H.-CONTENT TO STEROID SEX HORMONES

1960 ◽  
Vol XXXV (II) ◽  
pp. 245-252 ◽  
Author(s):  
G. P. van Rees ◽  
F. J. A. Paesi

ABSTRACT In the experiments reported in this paper the hypothesis that the decrease in the pituitary I. C. S. H.-content, which occurs after administration of steroid sex hormones in gonadectomized animals, is counteracted by a reflex stimulation of the hypophysis initiated by the operation has been investigated. If treatment with a low dose of testosterone propionate (100 μg) was started immediately after castration, the resulting decrease in the pituitary I. C. S. H.-content became more marked if the reflex stimulation of the hypophysis had been prevented. If, however, two months were allowed to elapse before the beginning of treatment, the presence or absence of this reflex was no longer of importance for the effect of testosterone propionate on the pituitary I. C. S. H.-content. And yet, in this case too, the decrease in the pituitary I. C. S. H.-content by testosterone propionate was less than in intact animals (see preceding paper). Hence this decrease appears to be counteracted by two factors: one rapidly occurring and short lasting, resulting from a reflex elicited by gonadectomy; the other gradually increasing in potency and possibly a direct consequence of the continued absence of pituitary inhibiting sex steroids.

1960 ◽  
Vol XXXV (II) ◽  
pp. 235-244 ◽  
Author(s):  
F. J. A. Paesi ◽  
G. P. van Rees

ABSTRACT The effect of chronic administration of sex hormones on the pituitary I. C. S. H.-content was studied in intact and gonadectomized rats. If the treatment of gonadectomized animals was not started until a considerable time had elapsed after the operation, the resulting decrease in the pituitary I. C. S. H.-content was less than expected on the basis of dose and duration of treatment. The hypothesis was investigated whether this is due to gradually evolving changes in the hypothalamo-hypophyseal system, initiated and caused by gonadectomy. In accordance with this conception, treatment of spayed female rats with high doses of oestradiol benzoate and testosterone propionate from the day after the operation onwards caused a fall in the pituitary I. C. S. H.-content to the same final level as was reached in intact control animals after treatment with these doses. However, if lower doses of oestradiol benzoate and testosterone propionate were given, there still remained a difference between intact and gonadectomized rats: again, the decrease in the pituitary I. C. S. H.-content was less in gonadectomized than in intact animals. There are two possibilities: a) in rats, testosterone propionate and oestradiol benzoate are not the physiological hormones responsible for the pituitary inhibition; b) castration induces rapid changes (e. g. by way of a reflex) in the hypothalamo-hypophyseal system, which increases the resistance to the influence of steroid sex hormones. The latter hypothesis which, according to available evidence, seems the more probable, will be discussed in a following paper.


1989 ◽  
Vol 62 (3) ◽  
pp. 711-722 ◽  
Author(s):  
T. Allison ◽  
G. McCarthy ◽  
C. C. Wood ◽  
P. D. Williamson ◽  
D. D. Spencer

1. The anatomic generators of human median nerve somatosensory evoked potentials (SEPs) in the 40 to 250-ms latency range were investigated in 54 patients by means of cortical-surface and transcortical recordings obtained during neurosurgery. 2. Contralateral stimulation evoked three groups of SEPs recorded from the hand representation area of sensorimotor cortex: P45-N80-P180, recorded anterior to the central sulcus (CS) and maximal on the precentral gyrus; N45-P80-N180, recorded posterior to the CS and maximal on the postcentral gyrus; and P50-N90-P190, recorded near and on either side of the CS. 3. P45-N80-P180 inverted in polarity to N45-P80-N180 across the CS but was similar in polarity from the cortical surface and white matter in transcortical recordings. These spatial distributions were similar to those of the short-latency P20-N30 and N20-P30 potentials described in the preceding paper, suggesting that these long-latency potentials are generated in area 3b of somatosensory cortex. 4. P50-N90-P190 was largest over the anterior one-half of somatosensory cortex and did not show polarity inversion across the CS. This spatial distribution was similar to that of the short-latency P25-N35 potentials described in the preceding paper and, together with our and Goldring et al. 1970; Stohr and Goldring 1969 transcortical recordings, suggest that these long-latency potentials are generated in area 1 of somatosensory cortex. 5. SEPs of apparently local origin were recorded from several regions of sensorimotor cortex to stimulation of the ipsilateral median nerve. Surface and transcortical recordings suggest that the ipsilateral potentials are generated not in area 3b, but rather in other regions of sensorimotor cortex perhaps including areas 4, 1, 2, and 7. This spatial distribution suggests that the ipsilateral potentials are generated by transcallosal input from the contralateral hemisphere. 6. Recordings from the periSylvian region were characterized by P100 and N100, recorded above and below the Sylvian sulcus (SS) respectively. This distribution suggests a tangential generator located in the upper wall of the SS in the second somatosensory area (SII). In addition, N125 and P200, recorded near and on either side of the SS, suggest a radial generator in a portion of SII located in surface cortex above the SS. 7. In comparison with the short-latency SEPs described in the preceding paper, the long-latency potentials were more variable and were more affected by intraoperative conditions.


2008 ◽  
Vol 99 (3) ◽  
pp. 1267-1273 ◽  
Author(s):  
Takeshi Suwabe ◽  
Hideyuki Fukami ◽  
Robert M. Bradley

Salivary secretion results from reflex stimulation of autonomic neurons via afferent sensory information relayed to neurons in the rostral nucleus of the solitary tract (rNST), which synapse with autonomic neurons of the salivatory nuclei. We investigated the synaptic properties of the afferent sensory connection to neurons in the inferior salivatory nucleus (ISN) controlling the parotid and von Ebner salivary glands. Mean synaptic latency recorded from parotid gland neurons was significantly shorter than von Ebner gland neurons. Superfusion of GABA and glycine resulted in a concentration-dependent membrane hyperpolarization. Use of glutamate receptor antagonists indicated that both AMPA and N-methyl-d-aspartate (NMDA) receptors are involved in the evoked excitatory postsynaptic potentials (EPSPs). Inhibitory postsynaptic potential (IPSP) amplitude increased with higher intensity ST stimulation. Addition of the glycine antagonist strychnine did not affect the amplitude of the IPSPs significantly. The GABAA receptor antagonist, bicuculline (BMI) or mixture of strychnine and BMI abolished the IPSPs in all neurons. IPSP latency was longer than EPSP latency, suggesting that more than one synapse is involved in the inhibitory pathway. Results show that ISN neurons receive both excitatory and inhibitory afferent input mediated by glutamate and GABA respectively. The ISN neuron response to glycine probably derives from descending connections. Difference in the synaptic characteristics of ISN neurons controlling the parotid and von Ebner glands may relate to the different function of these two glands.


1994 ◽  
Vol 77 (3) ◽  
pp. 1239-1245 ◽  
Author(s):  
M. Eljamal ◽  
L. B. Wong ◽  
D. B. Yeates

We questioned whether the prolonged stimulation of ciliary beat frequency (CBF) to a short exposure of low-dose capsaicin (Wong et al. J. Appl. Physiol. 68: 257–2580, 1990) could be due to the activation of indirect pathways involving neural reflexes initiated independently in the bronchi and alveoli. Tracheal CBF (CBFtr) was measured temporally in anesthetized groups of 10 dogs by means of heterodyne-mode correlation analysis laser light scattering. To elucidate the site of the afferent neural stimulation and the efferent mediators affecting the ciliated epithelium, capsaicin (3 nM) aerosol was delivered for 4 min, either predominantly to the bronchi or to the alveolar regions, with use of pulsed aerosol techniques. This resulted in 13 pg of bronchial (85%) and 10 pg of alveolar (96%) capsaicin deposited, which caused marked stimulation of CBFtr with maxima at 7 and 35 min, respectively. Prior administration of aerosolized indomethacin to the bronchi or aerosolized cromolyn to the alveoli inhibited the bronchial and alveolar responses, respectively. Prior administration of aerosolized hexamethonium to the tracheal lumen blocked the stimulatory CBFtr responses from both capsaicin challenges. Ipratropium or propranolol aerosols delivered to the tracheal lumen also inhibited these responses. It is proposed that these pathways comprise one set of sensitive mechanisms to ensure a prolonged stimulation of CBF to effect the removal of secretions and the irritant from the lungs.


2007 ◽  
Vol 88 (6) ◽  
pp. 1632-1636 ◽  
Author(s):  
Daniela Ostatníková ◽  
Peter Celec ◽  
Július Hodosy ◽  
Richard Hampl ◽  
Zdeněk Putz ◽  
...  

2020 ◽  
Vol 4 (3) ◽  
Author(s):  
Siyuan Yang ◽  
Zhiyong Cao ◽  
Jiabao Chen ◽  
Gang Fang

Objective: To study the effects of the ethnic medicine Polygala fallax Hemsl with Guangxi characteristics on the sex hormones and ?-EP in research objective perimenopausal rat models. Methods: 40 female SPF rats were randomly divided into 4 groups, including the normal, model, high-dose and low-dose groups. Rats of three groups except for the normal one were treated with perimenopausal modelling through the method of subcutaneous injection of compound 4-VCD for 15 consecutive days. Rats of the normal and model group were normally fed without any treatment. Rats of the high-dose and low-dose groups were administered by high- and low-dose intragastric administration of the extract of Polygala fallax Hemsl. According to the menstrual cycle of the vaginal smear of the rat, each menstrual cycle is a course of treatment and 6 consecutive courses of treatment would be given. The indexes of serum sex hormones (E2, FSH, LH) and ?-EP of rats in each group were observed after treatment. Results: After the treatment of 6 cycles, for the levels of ?-EP and E2, the model group was lowest (P<0.05), the normal group was highest (P<0.05); and the high-dose group was higher than the low-dose group; For the levels of FSH and LH, the normal group was lowest (P<0.05), the model group was highest (P<0.05), and the high-dose group was lower than the low-dose group. Conclusion: Guangxi characteristic national medicine Polygala fallax Hemsl can effectively improve the levels of serum sex hormones and ?-EP in perimenopausal rat models and relieve the related symptoms with a certain dose-effect relationship.


Author(s):  
Fernand Labrie ◽  
Céline Martel

AbstractObjective:Serum concentrations of estradiol (EMethods:Serum EResults:No biologically significant change in the individual serum concentrations of EConclusion:While the clinical program on vulvovaginal atrophy has shown the efficacy and safety of intravaginal 6.5 mg of DHEA (prasterone), the present data illustrate in detail the serum levels of the individual sex steroids and their metabolites derived from DHEA. The data obtained are in line with the physiology of intracrinology and confirm an action limited to the vagina as the serum concentrations of all sex steroids are maintained within the normal values of menopause, thus protecting the uterus and most likely other tissues.


PEDIATRICS ◽  
1962 ◽  
Vol 30 (6) ◽  
pp. 917-926
Author(s):  
Krishna M. Saxena ◽  
John D. Crawford

Lymphocytic thyroiditis was the most common cause of nontoxic goiters in childhood, comprising about 40% of these and 20% of all goiters seen in our pediatric endocrine clinic. The diagnosis should be considered whenever a nontoxic goiter does not diminish significantly in size within about two weeks in response to thyroid-stimulating-hormone (TSH) suppressive doses of USP thyroid. Observations on 32 children with lymphocytic thyroiditis have been recorded. The diagnosis was proven histologically in 23. In nine patients the diagnosis was presumptive. The condition occurred mostly in preadolescent girls as a slowly developing firm, diffuse, and smooth or nubbly goiter with or without symptoms of anxiety, nervousness and pressure in the neck. The majority of patients were euthyroid when first encountered, though examples both of mild hyperthyroidism and hypothyroidism were also seen. A high protein-bound iodine value, a large discrepancy between protein-bound iodine and butanol-extractable iodine, and positive tanned erythrocyte antibody test results provided the best diagnostic criteria apart from biopsy. The pathological picture is one of hyperplasia with lymphocytic infiltration and atrophy of thyroid follicles and epithelium. Treatment consisted in giving TSH suppressive doses of thyroid for a prolonged period. The results of treatment were not entirely satisfactory. Genetic predisposition, probably manifested in an abnormal cellular hypersensitivity, and excessive TSH stimulation of the thyroid seem for the moment the two factors in pathogenesis best supported by laboratory evidence.


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