Studies of Prolactin and TSH Secretion by Continuous Infusion of Small Amounts of Thyrotropin-Releasing Hormone (TRH)

Noel, Gordon L.; Dimond, Richard C.; Wartofsky, Léonard; Earll, Jerry M.; Frantz, Andrew G.

doi:10.1210/jcem-39-1-6

Cited by 117 publications

(37 citation statements)

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“…However, the low-est thyroid-stimulating hormone-releasing TRH dose already induces a prolactin response [19]. This response to TRH was blunted by treatment with flupenthixol or amisulpride.…”

Section: Discussionmentioning

confidence: 98%

Long-Term Effects of the Substituted Benzamide Derivative Amisulpride on Baseline and Stimulated Prolactin Levels

Schlößer¹,

Gründer²,

Anghelescu³

et al. 2002

Neuropsychobiology

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In the present study, we investigated the long-term effects of treatment with amisulpride, a substituted benzamide derivative, as compared with the effects of treatment with flupenthixol, a thioxanthene, on the prolactin levels in schizophrenic patients. After completing 6 weeks of medication with either amisulpride or flupenthixol, the patients entered a long-term maintenance treatment with amisulpride 200–600 mg/day or flupenthixol 5–15 mg/day for a maximum of 12 months with a subsequent drug-free follow-up until month 15. Eighteen initially included patients were still participating in the study at month 6. In the flupenthixol group, only 1 patient treated reached month 12, and none of the patients reached month 15. For the amisulpride treatment group, months 12 and 15 were completed by 9 and 6 patients, respectively. After 1, 3, 6, and 12 months of treatment, and finally 3 months after cessation of treatment, the basal and thyrotropin-releasing hormone-stimulated secretions of prolactin were investigated. The prolactin plasma levels were elevated in both treatment groups during the course of maintenance treatment with a maximum effect at month 1. Flupenthixol treatment initially raised the prolactin levels about two- or threefold, and a subsequent decline during months 3 and 6 occurred. However, only the changes for month 1 reached the level of a statistical trend. The prolactin secretion was initially increased over tenfold by amisulpride. The prolactin levels at months 1, 3, 6, and 12 were significantly elevated as compared with the baseline values. A continuous decline of prolactin levels in both treatment groups occurred over the course of the next months. The prolactin response after the thyrotropin-releasing hormone challenge was not significantly changed over the long-term course. Notably, in the amisulpride group, 3 months after cessation of treatment at month 12, the elevated levels of prolactin returned to baseline at month 15. In summary, amisulpride demonstrated more pronounced effects than flupenthixol on the prolactin levels. However, the findings indicate also that treatment with amisulpride at clinically effective doses can be achieved at significantly lower prolactin levels during the long-term maintenance phase than during the prior acute phase.

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Section: Discussionmentioning

confidence: 98%

Long-Term Effects of the Substituted Benzamide Derivative Amisulpride on Baseline and Stimulated Prolactin Levels

Schlößer¹,

Gründer²,

Anghelescu³

et al. 2002

Neuropsychobiology

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“…TRH induces prolactin release by a direct action on the pituitary gland and TRH regulation of prolactin gene transcription. 9 The role of TRH in the physiological surges of prolactin is unclear. Vasoactive intestinal peptide (VIP) has also been shown to stimulate prolactin release in isolated pituitary glands by increasing prolactin mRNA, possibly by the induction of cAMP.…”

Section: Neuroendocrine Regulation Of Prolactin Secretionmentioning

confidence: 99%

Physiopathology of prolactin secretion in obesity

Kopelman

2000

Int J Obes

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In many species prolactin is of biological importance and has a major role in determining the deposition and mobilization of fat. In human physiology, outside pregancy, prolactin secretion is altered by increasing body weight in both children and adults. Prolactin in this circumstance appears to be marker of hypothalamic ± pituitary function: the prolactin response to insulin-hypoglycaemia, thyrotrophin releasing hormone stimulation and other stimulatory factors may be diminished. In addition, obesity alters the 24 h spontaneous release of prolactin with a generalised dampening of release. A number of explanations have been given as possible causes for these alterations, but it seems likely that they re¯ect obesity per se and are associated with hyperinsulinaemia. Weight reduction, with accompanying decrease in plasma insulin levels, leads to a normalization of prolactin responses in most, but not all, circumstances. To date, no molecular basis has been identi®ed which links prolactin with increasing body fatness, weight and appetite: new data suggests a possible link in obese men between fasting plasma prolactin and leptin concentrations.

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“…12 The effect of sex on thyrotroph function is even more controversial. Significantly lower TSH response to TRH in young males compared to young females was found in some studies, 8,13,14 but not in others. 6,7,10,15 On the other hand, significantly diminished TSH response to TRH was found in elderly males compared to elderly females.…”

Section: Accepted For Publication 17 April 1995mentioning

confidence: 70%

“…Several studies have examined the effect of age and sex on the hypothalamic-pituitary-thyrotrophs axis by analyzing the TSH response to TRH injection [1][2][3][4][5][6][7][8][9][10][12][13][14][15][16][17] or to inhibitors of peripheral T 3 production. 11 Although the results were conflicting, most studies showed a diminished TSH response in the elderly and in males.…”

Section: Discussionmentioning

confidence: 99%

Influence of Age and Sex in Modulating TSH Level in Primary Hypothyroidism

Hammami

Al-Saihati

Alahmari

1995

Annals of Saudi Medicine

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Previous studies addressing the interaction of age and sex with the function of the hypothalamic-pituitarythyrotrophs axis yielded conflicting results, due in part to inability to control for the effect of variable free thyroid hormone levels. We studied the effect of age and sex on TSH levels in patients with severe primary hypothyroidism who have essentially undetectable plasma thyroid hormone levels. The TSH levels were measured in 116 thyroid cancer patients four weeks after the withdrawal of thyroxine therapy in preparation for radioiodine scan/treatment. All patients had a TSH ≥30 mU/L (normal = 0.2-5) and a free T 4 <6 pmol/L (normal = 10-25). Thirty males and 86 females with a mean age (± SD) of 40 ± 16 (range 6-89 years) were studied on up to four hypothyroid episodes, with a total of 191 episodes. The TSH level during the first hypothyroid episode correlated significantly with the TSH level during subsequent episodes (first episode versus second episode, r = 0.7, P -0.0001; first versus third episode, r = 0.6, P = 0.03). There was a significant negative correlation between age and TSH level (r = -0.24, P = 0.0009) that persisted when only the first hypothyroid episode was considered (r = -0.23, P = 0.01), or when only males (r = -0.32, P = 0.02) or only females (r = -0.23, P = 0.005) were considered. Means of TSH levels in males and females were not significantly different (130 versus 114 mU/L, respectively; P = 0.28). We conclude that age but not sex may modulate the sensitivity/responsiveness of the hypothalamic-pituitary thyrotroph axis to primary hypothyroidism. Ann Saudi Med 1995;15(6):575-578. MM Hammami, B Al-Saihati, S Al-Ahmari, Influence of Age and Sex in Modulating TSH Level in Primary Hypothyroidism. 1995; 15(6): 575-578 An age-related diminution in thyrotrophs function has been found by most, but not all, investigators. In response to an injection of a bolus of thyrotropin-releasing hormone (TRH), a decrease in thyroid-stimulating hormone (TSH) release was shown in elderly males and females, 1-3 in elderly males, 4 in elderly females, 5 and in elderly males but not in elderly females. [6][7][8][9][10] Further, the expected increase in TSH level in response to the inhibition of T 4 deiodination by oral iopanoic acid was not observed in healthy elderly volunteers.11 However, TSH response to a four-hour infusion of TRH was similar in the elderly compared to young male volunteers, although there was a small but significant increase in basal TSH concentration in the elderly. 12The effect of sex on thyrotroph function is even more controversial. Significantly lower TSH response to TRH in young males compared to young females was found in some studies, 8,13,14 but not in others. 6,7,10,15 On the other hand, significantly diminished TSH response to TRH was found in elderly males compared to elderly females. 16,17 A diminished TSH response to TRH could be due to: 1) decreased thyrotrophs capacity to secrete TSH (or decreased thyrotrophs sensitivity to TRH), and/or 2) increased sensitivity of...

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Studies of Prolactin and TSH Secretion by Continuous Infusion of Small Amounts of Thyrotropin-Releasing Hormone (TRH)

Cited by 117 publications

References 0 publications

Long-Term Effects of the Substituted Benzamide Derivative Amisulpride on Baseline and Stimulated Prolactin Levels

Long-Term Effects of the Substituted Benzamide Derivative Amisulpride on Baseline and Stimulated Prolactin Levels

Physiopathology of prolactin secretion in obesity

Influence of Age and Sex in Modulating TSH Level in Primary Hypothyroidism

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