Blunted HPA axis response in lactating, vasopressin-deficient brattleboro rats

Anna Fodor, Ottó Pintér, ágnes Domokos, Kristina Langnaese, István Barna, Mario Engelmann, Dóra Zelena

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Adaptation to stress is a basic phenomenon in mammalian life that is mandatorily associated with the activity of the hypothalamic-pituitary-adrenal (HPA) axis. Anincreased resting activity of the HPA axis can be measured during pregnancy and lactation, suggesting that these reproductive states lead to chronic load in females. In this study, we examined the consequences of the congenital lack of vasopressin on the activity of the HPA axis during lactation using vasopressin-deficient Brattleboro rats. Virgin and lactating, homozygous vasopressin-deficient rats were compared with control, heterozygous rats. In control dams comparedwith virgins, physiological changes similar to those observed in a chronic stress state (thymus involution, adrenal gland hyperplasia, elevation of proopiomelanocortin mRNA levels in the adenohypophysis, and resting plasma corticosterone levels) were observed. In vasopressin-deficient dams, adrenal gland hyperplasia and resting corticosterone level elevations were not observed. Corticotropin-releasing hormone (Crh)mRNA levels in the hypothalamic paraventricular nucleus were elevatedin only the control dams, while oxytocin (OT) mRNA levels were higher in vasopressin-deficient virgins and lactation induced a further increase in both the genotypes. Suckling-induced ACTH and corticosterone level elevations were blunted in vasopressin-deficient dams. Anaphylactoid reaction (i.v. egg white) and insulin-induced hypoglycemia stimulated the HPA axis, which were blunted in lactating rats compared with the virgins and in vasopressin-deficient rats compared with the controls without interaction of the two factors. Vasopressin seems to contribute to the physiological changes observed during lactation mimicking a chronic stress state, but its role in acute HPA axis regulation during lactation seems to be similar to that observed in virgins. If vasopressin is congenitally absent,OT, but not the CRH, compensates for the missing vasopressin; however, the functional restitution remains incomplete.

Original languageEnglish
Pages (from-to)89-100
Number of pages12
JournalJournal of Endocrinology
Volume219
Issue number2
DOIs
Publication statusPublished - Oct 22 2013

Keywords

  • ACTH
  • Brattleboro
  • Corticosterone
  • Crh mRNA
  • Lactation
  • Oxytocin mRNA
  • Pomc mRNA
  • Suckling,egg white
  • Vasopressin

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Endocrinology

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