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Relaxin contributes to the regulation of atrial pressure during pregnancy
Author(s) -
Denton Kate M,
Mirabito Collafella Katrina M,
Samuel Chrishan
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.851.10
Subject(s) - relaxin , medicine , endocrinology , gestation , mean arterial pressure , angiotensin ii , blood pressure , pregnancy , basal (medicine) , biology , hormone , heart rate , insulin , genetics
Relaxin is a potent vasodilatory and anti‐fibrotic hormone. Recently we demonstrated that these effects of relaxin are mediated via heterodimers formed between the cognate relaxin family receptor 1 (RXFP1) and the angiotensin type 2 receptor (AT 2 R). We, and others, have demonstrated that adult females are protected from the hypertensive effects of angiotensin II via an enhanced contribution of the AT 2 R in the regulation of arterial pressure and renal function as compared to age‐matched males and aged females. Moreover, during pregnancy, the refractoriness to angiotensin II is associated with an increase in the AT 2 R/AT 1 R ratio. In the present study we hypothesized that relaxin contributes to the regulation of arterial pressure in females at baseline and during pregnancy. Mean arterial pressure (MAP) was measured via radiotelemetry in 14 week‐old male and female wild‐type (WT; C67BL/6xSv129) and relaxin knockout (KO) mice and female relaxin KO mice. Thereafter, female mice were time‐mated with a (non‐telemetered) male of the same genotype and MAP was measured throughout gestation. Basal MAP was ~6 mmHg lower in WT females than males (P<0.05). Relaxin deficiency increased basal MAP in females (P<0.05 versus WT female), but not males. As expected, MAP decreased during gestation in WT mice, returning to near preconception levels during late gestation. Conversely, in relaxin KO mice, arterial pressure increased during mid and late gestation (P<0.05 as compared to WT). Moreover, relaxin deficiency impaired gestational weight gain and reduced litter size. This is the first study i) to demonstrate that relaxin contributes to the sexual dimorphism of arterial pressure in mice and ii) to document the changes in the arterial pressure profile of pregnant relaxin KO mice. Understanding the mechanisms that underlie the regulation of arterial pressure in females of reproductive age may uncover new strategies to treat hypertension in women and men