Aims The influence of prenatal factors on the development of arterial hypertension has gained considerable interest in recent years. We examined the effects of prenatal testosterone treatment on blood pressure in adult female rats. Further, to define the mechanisms whereby blood pressure may be raised, we examined vascular endothelial function and nitric oxide synthesis. Methods and Results Testosterone propionate (0.5mg/kg/day;SC) or vehicle was administered to pregnant Sprague-Dawley rats from gestational day 15–19. Maternal feed intake and plasma levels of steroid hormones were measured in the dams. In the female offspring, birth weight, growth rate, blood pressure, vascular reactivity, eNOS expression, and nitric oxide production were examined. In the pregnant rats, testosterone-treatment increased plasma testosterone levels by 2-fold without any significant changes in 17β-estradiol, progesterone and corticosterone levels. Testosterone-treatment did not affect maternal feed intake. The pups born to testosterone mothers were smaller in size but exhibited catch-up growth. The blood pressure in the testosterone offspring at 6 months of age was significantly higher compared to controls. Endothelium-intact mesenteric arteries from testosterone group exhibited increased contractile responses to phenylephrine, decreased vasodilation to acetylcholine and unaltered responses to sodium nitroprusside in comparison to control rats. Testosterone rats demonstrated decreased expression for eNOS, and reduced nitric oxide production. Conclusions Our data show that elevated plasma maternal testosterone levels: (1) causes low birth weight followed by catch-up growth and hypertension in female offspring; (2) alters endothelium-dependent vascular responses. The endothelial dysfunction is associated with decreased activity/expression of eNOS.

Sex steroid hormones estradiol and progesterone play an important role in vascular adaptations during pregnancy. However, little is known about the role of androgens. Plasma testosterone (T) levels are elevated in preeclampsia, mothers with polycystic ovary, and pregnant African-American women, who have endothelial dysfunction and develop gestational hypertension. We tested whether elevated T alters vascular adaptations during pregnancy and if these alterations depend upon endothelium-derived factors such as prostacyclin, endothelium-derived hyperpolarizing factor (EDHF), and nitric oxide (NO). Pregnant Sprague Dawley rats were injected with vehicle (n=12) or T propionate [0.5 mg/Kg/day from gestation day (GD) 15–19;n=12] to increase plasma T levels 2-fold, similar to that observed in preeclampsia. Telemetric blood pressures and endothelium-dependent vascular reactivity were assessed with wire-myograph system. Phospho-eNOS and total-eNOS were examined in mesenteric arteries (MA). Mean arterial pressures were significantly higher starting from GD19 until delivery in T-treated dams. Endothelium-dependent relaxation responses to acetylcholine were significantly lower in MA of T-treated dams (pD2 (-log EC50)=7.05±0.06; Emax=89.4±1.89) compared to controls (pD2=7.38±0.04; Emax=99.9±0.97). Further assessment of endothelial factors showed NO-mediated relaxations were blunted in T-treated MA (Emax=45.4±5.48) compared to controls (Emax=76.49±5.06); however, prostacyclin- and EDHF-mediated relaxations were unaffected. Relaxation to sodium nitroprusside was unaffected with T-treatment. Phosphorylations of eNOS at Ser1177 were decreased and at Thr495 were increased in T-treated MA without changes in total-eNOS levels. In conclusion, elevated maternal T, at concentrations relevant to abnormal clinical conditions, cause hypertension associated with blunting of NO-mediated vasodilation. Testosterone may induce the increased vascular resistance associated with pregnancy-induced hypertension.

Prenatal testosterone exposure impacts postnatal reproductive and endocrine function, leading to alterations in sex steroid levels. Because gonadal steroids are key regulators of cardiovascular function, it is possible that alteration in sex steroid hormones may contribute to development of hypertension in prenatally testosterone-exposed adults. The objectives of this study were to evaluate whether prenatal testosterone exposure leads to development of hypertension in adult males and females and to assess the influence of gonadal hormones on arterial pressure in these animals. Offspring of pregnant rats treated with testosterone propionate or its vehicle (controls) were examined. Subsets of male and female offspring were gonadectomized at 7 wk of age, and some offspring from age 7 to 24 wk received hormone replacement, while others did not. Testosterone exposure during prenatal life significantly increased arterial pressure in both male and female adult offspring; however, the effect was greater in males. Prenatal androgen-exposed males and females had more circulating testosterone during adult life, with no change in estradiol levels. Gonadectomy prevented hyperandrogenism and also reversed hypertension in these rats. Testosterone replacement in orchiectomized males restored hypertension, while estradiol replacement in ovariectomized females was without effect. Steroidal changes were associated with defective expression of gonadal steroidogenic genes, with Star, Sf1, and Hsd17b1 upregulation in testes. In ovaries, Star and Cyp11a1 genes were upregulated, while Cyp19 was downregulated. This study showed that prenatal testosterone exposure led to development of gonad-dependent hypertension during adult life. Defective steroidogenesis may contribute in part to the observed steroidal changes.

Objective To determine the effects of fetal sex on aromatase and androgen receptor (AR) expression in the placenta of normal and preeclamptic pregnancies. Study Design Placenta from preeclamptic (5-female and 6-male fetus) and healthy pregnancies (7-female and 7-male fetus) were examined by immunofluorescence, Western blotting and quantitative-RT-PCR. Results Placental AR levels were significantly higher (P<0.05) in placentae of both male and female fetus compared to their respective sexes in normal pregnancies. The placental aromatase levels varied depending on fetal sex. If the fetus was female, aromatase levels were substantially higher (P<0.05) in preeclamptic than normal placentae. If the fetus was male, the aromatase levels were significantly lower (P<0.05) in preeclamptic than normal placentae. Placental aromatase levels were significantly higher (P<0.05) in male-than in female-bearing normal placentae. Conclusion Dysregulation in androgen production and signaling in preeclamptic placentae may contribute to placental abnormalities increasing the frequency of maternal-fetal complications associated with preeclampsia.

Objective Examine temporal alterations in vascular angiotensin II (ANG II) receptors (AT1R and AT2R) and determine vascular response to ANG II in growth-restricted offspring. Study design Offspring of pregnant rats fed low-protein (6%) and control (20%) diet were compared. Results Prenatal protein restriction reprogrammed AT1aR mRNA expression in males’ mesenteric arteries to cause 1.7- and 2.3-fold increases at 3 and 6 months of age associated with arterial pressure increases of 10 and 33 mmHg, respectively; however, in females, increased AT1aR expression (2-fold) and arterial pressure (15 mmHg) occurred only at 6 months. Prenatal protein restriction did not affect AT2R expression. Losartan abolished hypertension, suggesting that AT1aR plays a primary role in arterial pressure elevation. Vasoconstriction to ANG II was exaggerated in all protein-restricted offspring, with greater potency and efficacy in males. Conclusion Prenatal protein restriction increased vascular AT1R expression and vasoconstriction to ANG II, possibly contributing to programmed hypertension.