Altered hypothalamic monoamine metabolism and pituitary prolactin regulation in female spontaneously hypertensive rats

Steger, Richard W.; Avila-Jimenez, R.; Amador, A. G.; Johns, Anthony

doi:10.1016/0024-3205(84)90641-6

Cited by 9 publications

(12 citation statements)

References 14 publications

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“…Injection of 0.5 and 1 ug of LHRH-A increased plasmatic FSH above the basal value in WKY 15, 30, 60 and 120 min after treat ment, whereas in SHR a significant increase was only ob served 120 min after the administration of 0.5 pg of Besides modifications previously observed in the regu lation of prolactin [3], TSH [5,7], GH [9], and LH [4], the above results clearly demonstrate that SHR have altered mechanisms controlling the synthesis and secretion of FSH. These alterations were more pronounced in male rats in which the function of the hypothalamic-pituitarytesticular axis is clearly affected.…”

Section: Fsh and Lh Responses To Lhrh-amentioning

confidence: 80%

“…The reduced hypothalamic noradrenergic activity in SHR [3,42] cannot explain the increased LHRH secretion since noradrenaline stimulates LHRH secretion [33,34], The functionality of other systems modulating LHRH secretion in male SHR is unknown. Some of the hormones engaged in regulating blood press ure are expressed at the hypothalamic-pituitary unit and influence the pituitary-testicular axis.…”

Section: Fsh and Lh Responses To Lhrh-amentioning

confidence: 99%

“…Some of the aforementioned neurotransmitters and neuropeptides may be involved in the possible increased secretion of LHRH in SHR males. A juxtaposition between dopaminergic, noradrenergic and LHRH neurones exists at the median eminence [41], If we assume that dopamine inhibits LHRH secretion [39,40], the proposed central dopaminergic insufficiency in SHR [3,5] may increase LFIRH secretion in this strain.…”

Section: Fsh and Lh Responses To Lhrh-amentioning

confidence: 99%

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Changes in Follicle-Stimulating Hormone Secretion in Spontaneously Hypertensive Rats

Aguilar

Padilla²,

Bellido³

et al. 1992

Neuroendocrinology

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FSH and testosterone plasma levels, pituitary FSH content and concentration and the weight of testis, seminal vesicles and ventral prostate have been studied at the ages of 30, 60 and 90 days in spontaneously hypertensive rats (SHR) and normotensive control (WKY) rats. In vitro FSH secretion by pituitaries, and the response to orchidectomy and to exogenous administration of either LHRH (1 µg) or LHRH agonist (0.05, 0.1, 1, and 5 µg/kg) were analyzed in 90-day-old SHR and WKY male rats. Ventral prostate weight and FSH plasma levels were determined in other groups of adult male rats castrated and castrated and implanted for 15 days with silastic capsules containing testosterone, dihydrotestosterone or estradiol. Also FSH plasma levels and pituitary FSH concentration were determined at the ages of 30, 60 and 90 days in SHR and WKY female rats. Male SHR showed increased plasma FSH levels and high testicular weight in all the cases, and enhanced testosterone levels in plasma and pituitary FSH content on days 60 and 90. Weight of seminal vesicles and ventral prostate was normal or reduced, depending on the animal age. Adult SHR had increased FSH secretion in vitro, normal response to orchidectomy and did not exhibit FSH increases after LHRH administration. The efficiency of testosterone to stimulate ventral prostate growth and the ability of estradiol to reduce FSH plasma levels were decreased in SHR. Female SHR showed a significant increase in the pituitary content of FSH on day 30 and on proestrus at the ages of days 60 and 90. These results demonstrate that the mechanisms controlling FSH secretion were altered in SH male rats, resulting in an increase in the secretion and pituitary content of FSH and a reduction in the pituitary responsiveness to LHRH. The simultaneous increase in FSH and testosterone plasma levels suggested that the set-point of the feedback mechanisms was changed, whereas the precise involvement of LHRH and other hormones engaged in regulating blood pressure such as atrial natriuretic factor, vasopressin and endothelins in the effects now described needed further experimentation.

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Section: Fsh and Lh Responses To Lhrh-amentioning

confidence: 80%

Section: Fsh and Lh Responses To Lhrh-amentioning

confidence: 99%

Section: Fsh and Lh Responses To Lhrh-amentioning

confidence: 99%

See 1 more Smart Citation

Changes in Follicle-Stimulating Hormone Secretion in Spontaneously Hypertensive Rats

Aguilar

Padilla²,

Bellido³

et al. 1992

Neuroendocrinology

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“…SH rats show anomalies in the secretion of pituitary hor mones, which results in an increase in LH. FSH and prolactin plasma levels [4,22,28,32]. The pituitary responsiveness to hypothalamic hormones seems to be affected in spontaneously hypertensive (SH) rats that exhibited increased TSH and Prl re sponses to TRH [31], and decreased ACTH and gonadotro phins responses to CRF[I3] and LHRH [23,31].…”

mentioning

confidence: 99%

“…was also studied, be cause of the dopamine modulation of pituitary responsiveness to GRF [ 1,15,25] and the probable alteration of dopamine and serotonin metabolism in SH rats [32]. …”

mentioning

confidence: 99%

Changes in Growth Hormone Secretion in Spontaneously Hypertensive Rats

Aguilar¹,

Rodríguez²,

Bellido³

et al. 1990

Neuroendocrinology

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Secretion of the growth hormone (GH) in spontaneously hypertensive (SH) male rats has been determined and compared with that of normotensive Wistar-Kyoto (WKY) controls. In a first set of experiments, plasma GH concentration and pituitary GH content were measured in SH rats 30, 60 and 90 days old. 30-day rats showed reduced GH plasma and pituitary levels, whereas in 60- and 90-day-old rats no differences in GH plasma concentration and increased GH pituitary content were observed. In a second set of experiments, 90-day-old SH male rats anesthetized with sodium pentobarbital and intravenously injected with growth hormone-releasing factor (GRF) showed an amplitude and duration of response to injected hormone higher than WKY controls. In a third set of experiments, hemipituitaries of 90-day-old SH males were incubated for 2 h in Krebs-Ringer-bicarbonate either in the presence or in the absence of GRF. In the absence of GRF stimulation, the in vitro release of GH was higher than in WKY controls, whereas in the presence of GRF the sensitivity and the maximum response to GRF was reduced in comparison with normotensive male rats. These results indicate that SH rats have decreased pituitary content and plasma GH concentration before puberty. Besides, they showed increased pituitary GH content in adulthood and opposite changes in the in vivo and in vitro response to GRF.

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The activity of catecholamine synthesis in the hypothalamus of female normotensive Wistar Kyoto and spontaneously hypertensive rats

Hashimoto

Kimura

1991

Brain Research

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Altered hypothalamic monoamine metabolism and pituitary prolactin regulation in female spontaneously hypertensive rats

Cited by 9 publications

References 14 publications

Changes in Follicle-Stimulating Hormone Secretion in Spontaneously Hypertensive Rats

Changes in Follicle-Stimulating Hormone Secretion in Spontaneously Hypertensive Rats

Changes in Growth Hormone Secretion in Spontaneously Hypertensive Rats

The activity of catecholamine synthesis in the hypothalamus of female normotensive Wistar Kyoto and spontaneously hypertensive rats

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