Document Detail

Stimulated thyrotropin and prolactin secretion in lactating and non-lactating women.
MedLine Citation:
PMID:  8540286     Owner:  NLM     Status:  MEDLINE    
During the postpartum period, lactation is initiated by a massive release of prolactin which, in turn, reflects reduced dopaminergic inhibition of the pituitary lactotrophs. This postpartum prolactin rise can be prevented by administration of dopamine agonists. The release of thyrotropin (TSH) is also controlled by dopaminergic inputs and, therefore, TSH secretion may also be affected by postpartum alterations in dopaminergic activity. To gain further insight into the regulation of TSH and prolactin secretion during the postpartum period, we compared the basal and stimulated TSH and prolactin levels of postpartum lactating (n = 10) and non-lactating women (treated with 5 mg bromocriptine daily, n = 9) with those of normal cycling women (n = 9). Frequent blood samples were obtained on postpartum day 5 or in the early follicular phase before and after administration of thyrotropin-releasing hormone (TRH) for serial determination of TSH and prolactin by immunoradiometric assay (IRMA). Based serum prolactin levels were high (p < 0.001) in lactating women and low in both non-lactating and normal cycling women. When these differences in the basal prolactin concentrations were taken into account, the stimulated prolactin release (relative prolactin increase and area under the prolactin curve) was found to be highest (p < 0.05) in non-lactating women and lowest in lactating women. Basal TSH secretion was not significantly different between the groups of women (p > 0.2). Yet, both the relative TSH increases and the response curves following TRH stimulations were high (p < 0.05) in normal cycling women and low in both lactating and non-lactating postpartum women. These observations confirm a difference in the basal and stimulated prolactin release between lactating and non-lactating women. They also indicate that the TRH-stimulated TSH release is greatly affected by the postpartum state, irrespective of lactation or therapeutic weaning. The observation of a decreased sensitivity of pituitary thyrotrophs in concert with unchanged basal TSH secretion is suggestive of changes in hypothalamic TRH secretion and/or in the TSH metabolic half-life during the postpartum period.
W G Rossmanith; B Hohl; B Lüttke
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Gynecological endocrinology : the official journal of the International Society of Gynecological Endocrinology     Volume:  9     ISSN:  0951-3590     ISO Abbreviation:  Gynecol. Endocrinol.     Publication Date:  1995 Sep 
Date Detail:
Created Date:  1996-02-08     Completed Date:  1996-02-08     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8807913     Medline TA:  Gynecol Endocrinol     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  181-8     Citation Subset:  IM    
Department of Obstetrics and Gynecology, University of Ulm, Germany.
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MeSH Terms
Bromocriptine / pharmacology,  therapeutic use
Dopamine / physiology
Immunoradiometric Assay
Lactation / physiology*
Postpartum Period
Prolactin / secretion*
Thyrotropin / secretion*
Thyrotropin-Releasing Hormone / diagnostic use
Reg. No./Substance:
24305-27-9/Thyrotropin-Releasing Hormone; 25614-03-3/Bromocriptine; 9002-62-4/Prolactin; 9002-71-5/Thyrotropin

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