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Baroreflex gain and insulin sensitivity change in parallel during gestation in rats
Author(s) -
Zhao Ding,
Azar Afaf S.,
Page Mollie,
Brooks Virginia L.
Publication year - 2009
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.23.1_supplement.609.1
Subject(s) - gestation , endocrinology , medicine , baroreflex , insulin , pregnancy , blood pressure , heart rate , chemistry , biology , genetics
Pregnancy (P) decreases baroreflex gain (BRG). Our recent studies in rabbits suggest that decreases in insulin sensitivity (IS) contribute to the BRG impairment: BRG falls in parallel with IS at end gestation, and treatment with the insulin sensitizing drug, rosiglitazone, normalizes BRG. In rats, IS falls at midgestation (days 11‐12 of 21 day gestation), rises to normal by day 15, and then decreases again just before delivery. However, whether BRG exhibits a similar pattern, or whether IS and BRG increase in parallel postpartum (PP), is unknown. To test these hypotheses, BRG was measured in conscious virgin (V) rats, during P [days 11‐12 (P12), 17‐18 (P18), and 19‐20 (P20)], and on PP days 3‐4 (PP3) from a 4 parameter sigmoidal fit of heart rate responses to slow (3‐5 min) ramp changes in arterial pressure. In addition, we measured IS using the hyperinsulinemic‐euglycemic clamp method in V, P20 and PP3 rats. Compared to V rats (4.5±0.5 bpm/mmHg, n=10), BRG was decreased (P<0.05) on P12 (2.8±0.1 bpm/mmHg, n=7) and P20 (2.3±0.4 bpm/mmHg, n=8); however, BRG on P18 (3.8±0.1 bpm/mmHg, n=5) and PP3 (5.9±0.2 bpm/mmHg, n=3) were not different from V. Similarly, IS was decreased on P20 (V, 32±2 mg/kg•min, n=6; P20, 14±1 mg/kg•min, n=3; P<0.05) but normalized by PP3 (30±2 mg/kg•min, n=8). In conclusion, BRG and IS change in parallel during and following rat gestation, suggesting a mechanistic link. Supported by AHA, NIH HL088552.