VARIATIONS IN PLASMA RENIN DURING THE MENSTRUAL CYCLE

Follicular fluid renin concentration in patients with polycystic ovaries treated with gonadotrophins in an in vitro fertilisation programme

The initial hypothesis was that the follicular fluid prorenin concentration was higher in women with polycystic ovaries (PCO) compared to normally cycling women stimulated by gonadotrophins. In a controlled prospective study, 47 women undergoing in vitro fertilisation (IVF) were enrolled: 20 women with PCO represented the study group and 27 normally cycling women the control group. Plasma prorenin, active renin, serum oestradiol, and androstenedione concentrations were measured on the day of human chorionic gonadotrophin (HCG) administration and 36 hours after HCG administration. Follicular fluid prorenin, active renin, oestradiol, and androstenedione concentrations from the dominant follicle and pooled follicles were measured 36 hours after HCG administration. Plasma prorenin concentration 36 hours after HCG administration was significantly higher in the PCO group (1867 microU/l; range 1137-3162 microU/l) than in controls (860 microU/l; range 433-1763 microU/l) (p = 0.007). The follicular fluid prorenin concentration in the dominant follicle and in the pooled follicles was lower in the PCO group (20190 microU/l; range 11130-25955 microU/l) than in controls (46930 microU/l; range 20671-66171 microU/l) (p = 0.003). We conclude that plasma prorenin concentrations in gonadotrophin-stimulated PCO cycles are augmented due to numerous follicles. Lower follicular fluid prorenin concentrations in women with PCO show that the synthesis of prorenin in theca cells starts later after HCG administration than in normally cycling women.

Renal segmental tubular response to salt during the normal menstrual cycle

BACKGROUND

It has been suggested that women gain weight and develop peripheral edema during the luteal phase of the menstrual cycle because they tend to retain sodium and water. However, there is actually no clear evidence for physiological, cyclic variations in renal sodium handling during the menstrual cycle. We prospectively assessed the changes in segmental renal sodium handling occurring during the menstrual cycle in response to changes in salt intake.

METHODS

Thirty-five normotensive women were enrolled. Seventeen women were randomized and studied in the follicular and 18 in the luteal phases of their menstrual cycle. All women were assigned at random to receive a low (40 mmol/day) or a high (250 mmol/day) sodium diet for seven days on two consecutive menstrual cycles. Renal sodium handling and hemodynamics were measured at the end of each diet period.

RESULTS

The changes in sodium intake induced comparable variations in sodium excretion in both phases of the menstrual cycle. In the follicular phase, the increase in salt intake was associated with no change in renal hemodynamics, an increased fractional excretion of lithium (FELi) and a decreased fractional distal reabsorption of sodium (FDRNa), suggesting that sodium reabsorption is reduced both in the proximal and the distal tubules. In contrast, in the luteal phase, the renal response to salt was characterized by a significant renal vasodilation and a marked salt escape from the distal nephron, compared to the women investigated in the follicular phase (P < 0.01). Sodium reabsorption by the proximal nephron was not reduced as indicated by the unchanged FELi.

CONCLUSIONS

These results show that the segmental renal handling of sodium differs markedly in the two phases of the menstrual cycle. They suggest that the female hormones modulate the renal handling of sodium at the proximal and distal segments of the nephron in young normotensive women.

Prorenin is elevated in polycystic ovary syndrome and may reflect hyperandrogenism

OBJECTIVE

To examine the null hypothesis that women with polycystic ovary syndrome (PCOS) produce similar levels of prorenin and other components of the ovarian-derived prorenin to angiotensin cascade (ODPAC) at baseline and after stimulation with clomiphene citrate (CC) or hMG when compared with normal age- and weight-matched ovulatory controls.

DESIGN

Prospective controlled clinical trial.

SETTING

Infertility clinic in a university-based county hospital and a hospital-based private infertility practice.

PATIENTS

Twenty-eight infertile women aged 18 to 35 years. Thirteen patients were diagnosed with PCOS. Fifteen normal ovulatory patients who were matched for age and weight served as controls.

INTERVENTIONS

Twenty patients were stimulated with CC and eight were stimulated with hMG.

MAIN OUTCOME MEASURES

Serum E2, P, T, androstenedione (A), DHEAS, LH, FSH, and plasma prorenin, active renin, and angiotensin II (Ang II) were measured at baseline and during the preovulatory and midluteal phases of the stimulation cycles.

RESULTS

Baseline plasma prorenin in PCOS was higher than that of follicular phase controls. Plasma prorenin correlated significantly with peripheral androgen levels. Prorenin, active renin, and Ang II increased in response to gonadotropins with the largest increases occurring in control patients receiving CC. An association was seen between ovulation with CC and lower baseline levels of active renin.

CONCLUSIONS

The null hypothesis was rejected. Infertile women with PCOS have higher baseline prorenin levels when compared with age- and weight-matched ovulatory controls. There is a significant correlation between prorenin and the peripheral levels of androgens produced during ovarian stimulation. Baseline active renin levels may be predictive of ovulation with CC.

Angiotensin converting enzyme inhibition of the gonadotropin-stimulated rabbit: effect on estradiol production

PURPOSE

Our purpose was to determine whether angiotensin converting enzyme (ACE) inhibitors affect gonadotropin-stimulated estradiol (E2) production.

DESIGN

This was a prospective, masked, randomized, placebo-controlled animal trial. Twenty female New Zealand White rabbits were hyperstimulated with gonadotropins. One-half of the rabbits received concomitant treatment with the ACE inhibitor, enalapril; one-half received concomitant treatment with a placebo.

RESULTS

Baseline peripheral E2 (13 +/- 4 vs 11 +/- 2 pg/ml) and angiotensin II (Ang II) (22 +/- 5 vs 27 +/- 7 pg/ml) levels were similar in both groups. Significant inhibition of peripheral Ang II levels was achieved in the enalapril group (32 +/- 6 vs 93 +/- 15 pg/ml; P = 0.005). E2 was significantly higher in the rabbits receiving enalapril versus placebo (369 +/- 58 vs 183 +/- 35 pg/ml, P < 0.03), respectively. By day 10, peripheral E2 had returned to normal levels in both groups (13 +/- 1 vs 13 +/- 1 pg/ml). However, E2 levels in the ovarian effluent were 2.8 times higher in the enalapril rabbits.

CONCLUSION

Peripheral Ang II levels increase after gonadotropin stimulation and ACE inhibitors are able to blunt this increase significantly. ACE inhibition has a significant stimulatory effect on ovarian E2 production. This implies that Ang II may normally inhibit ovarian E2 production in stimulated cycles.

Ovarian derived prorenin-angiotensin cascade in human reproduction

OBJECTIVE

To review the available literature concerning the renin-angiotensin system of the human and animal ovary and to outline the clinical relevance of this system.

DESIGN

The location, function, and regulation of the components of the ovarian prorenin cascade are described. The possible functions of this system as well as its association with common gynecologic problems are also given.

CONCLUSIONS

The ovary contains a complete cascade whose end product is the formation of angiotensin II. Angiotensin II may have a role in steroid synthesis, oocyte maturation, ovulation, and corpus luteum formation. Further, aberrations in this system are associated with ovarian tumors, ectopic pregnancy, pre-eclampsia, and ovarian hyperstimulation syndrome.

Age-related changes in the renin-aldosterone system. Physiological effects and clinical implications

Age-related changes in the renin-aldosterone system in normal humans are well documented. The most pronounced changes are observed at the extremes of life: plasma renin activity and plasma aldosterone levels are highest in the newborn, and lowest in the elderly population. There is a close temporal and directional relationship between the age-related decrease in plasma renin activity and the age-related decrease in plasma aldosterone. The renin-aldosterone system is also influenced by sex and race. The activation of the renin-aldosterone system in newborns and infants probably represents an important physiological mechanism designed to maintain positive sodium balance. The decreases in plasma renin activity and plasma aldosterone levels observed in elderly persons are usually only modest, and are not associated with clinical alterations in fluid or electrolyte metabolism. The superimposition of a disease process, or the injudicious prescription of a drug, inhibiting renin release or angiotensin II production, could theoretically facilitate sodium wasting in newborns or infants, or precipitate hyporeninaemic hypoaldosteronism in older adults. The primary clinical importance of age-related changes in the renin-aldosterone system relates to its impact on the proper classification of an individual's renin-aldosterone profile when attempting to diagnose a clinical condition (e.g. low, normal or high renin hypertension). This is particularly true for newborns, infants and children to age 4, and for adults entering the sixth decade of life.

Renal sodium retention does not occur during the luteal phase of the menstrual cycle in normal women

OBJECTIVE

To determine whether weight gain due to renal sodium and water retention occurs in the luteal phase of the normal menstrual cycle.

DESIGN

Prospective observational study.

SETTING

Research laboratory installed with modified spa bath.

SUBJECTS

Ten normal healthy women.

INTERVENTION

Each subject underwent two experiments, one in each phase of the menstrual cycle, involving 3 h head-out water immersion and a pre- and post immersion control hour. 25 ml blood samples were obtained every hour before, during and after water immersion.

MAIN OUTCOME MEASURES

Renal and hormonal responses to water immersion during the luteal and proliferative phases of the cycle.

RESULTS

There was no change in weight, creatinine clearance, basal sodium excretion or plasma atrial natriuretic peptide between the two phases of the cycle. There was a significant rise in basal progesterone, plasma aldosterone and plasma renin activity in the luteal phase of the ovulatory cycles. Renal and hormonal responses to immersion including sodium and calcium excretion, elevation of atrial natriuretic peptide (ANP) and suppression of plasma aldosterone and plasma renin activity were identical in the two phases of the menstrual cycle.

CONCLUSION

We found no evidence to support the hypothesis that renal sodium and water retention occurs in the luteal phase of the normal menstrual cycle.

Ovarian renin production in vitro and in vivo: characterization and clinical correlation

The purpose of this study was to examine the in vitro production of prorenin and active renin by human theca cells and to examine the clinical significance of this production by correlating prorenin and active renin levels with oocyte maturity in follicular fluid samples. Human theca cell cultures were established and were found to produce both prorenin as well as active renin. Androstenedione levels (126 +/- 28 pg/500,000 cells/24-hr incubation) correlated with prorenin levels (8.5 +/- 1.1 ng angiotensin I per milliliter per hour (AI/ml/hr) in culture supernatant (r = 0.61, P less than 0.05). Active renin levels in follicular fluid were higher in stimulated versus spontaneous cycles (359 +/- 67 versus 126 +/- 37 ng AI/ml/hr, P less than 0.05). Renin substrate levels were similar in follicular fluid and in the peripheral serum (1,610 +/- 216 versus 2,160 +/- 490 ng/ml) in spontaneous cycles. Follicular fluid prorenin and active renin did not correlate with oocyte maturity or with steroid levels. The authors conclude that ovarian theca cells produce renin in vitro. However, renin production does not correlate with oocyte maturity or follicular fluid steroids in vivo.

Gradients of prorenin and active renin in ovarian venous and peripheral venous blood samples obtained simultaneously

Previous studies have demonstrated the presence of prorenin, active renin, and angiotensin II in human follicular fluid. The purpose of this study was to analyze prorenin, active renin, and ovarian steroids in ovarian venous blood and peripheral venous blood samples obtained simultaneously. We studied 10 premenopausal patients undergoing oophorectomy in various phases of the menstrual cycle. Prorenin levels in the ovarian venous effluent were more than twofold higher than levels in peripheral blood, 136.8 +/- 34.1 versus 35.6 +/- 8.3 ng angiotensin 1 per milliliter per hour (p less than 0.01). Active renin levels were also higher in ovarian venous blood than in peripheral venous blood, 12.9 +/- 2.5 versus 8.9 +/- 2.7 ng angiotensin 1 per milliliter per hour, but this difference did not achieve statistical significance (p = 0.07). Prorenin levels correlated with those of active renin in ovarian venous blood (r = 0.76, p less than 0.05), suggesting that prorenin is locally activated. In the peripheral circulation, estradiol levels correlated negatively with prorenin levels (r = -0.73, p less than 0.05), although prorenin levels did not correlate with steroid levels in ovarian venous blood. We conclude that prorenin is produced by the ovary throughout the menstrual cycle and may be locally activated.

The ovarian prorenin-angiotensin system. Lessons from IVF

Recent evidence suggests that prorenin and other active components of the renin-angiotensin system may be linked to ovarian physiology. Prorenin, the inactive form of the enzymatically active renin, is present in the fluid of mature human ovarian follicles in concentrations more than 10 times higher than that found in the plasma of women undergoing ovarian stimulation. Only 1% of the renin in follicular fluid is in active form. Concentrations of prorenin in fluid of immature follicles are lower than levels detected in concomitantly aspirated mature follicles. Study of prorenin levels disclosed a positive correlation to testosterone and E2 in fluids of mature follicles. Plasma prorenin increases about twofold at midcycle at the time of the LH surge; the peak of prorenin is sustained for about 40 hours. In patients undergoing ovarian stimulation for IVF, hCG administration results in much higher plasma prorenin levels and the height of prorenin response is directly related to the number of mature follicles. It peaked 4 to 6 days after hCG injection and then fell, close to baseline, by about 12 days after hCG administration. Examination of the time course of hormonal changes in response to hCG revealed a temporal relationship between prorenin and both plasma E2 and progesterone. In women who conceived, prorenin began to rise again on days 8 to 12 after embryo transfer when endogenous hCG was detected in the blood. No such changes in prorenin occurred in women with ovarian failure who conceived after transfer of a donor egg. These findings indicate that prorenin is produced by the mature follicle and the corpus luteum in response to LH/hCG. Since angiotensin II affects intracellular calcium and phospholipase activity, there are many potential roles for prorenin via angiotensin II action. Putative actions of the ovarian renin system may include control of oocyte maturation, ovulation, ovarian blood flow, and ovarian steroid biosynthesis. Future work to elucidate the function of this new renin system may have relevance to many basic and clinical aspects of human reproduction.

Plasma prorenin response to human chorionic gonadotropin in ovarian-hyperstimulated women: correlation with the number of ovarian follicles and steroid hormone concentrations

Plasma prorenin and active renin were measured before and after human chorionic gonadotropin (hCG) administration in two groups of patients undergoing ovarian stimulation for 4-6 days with follicle-stimulating hormone alone or in combination with luteinizing hormone, for in vitro fertilization. Baseline total plasma renin (prorenin plus active renin; n = 12) averaged 25 +/- 8 ng/ml per hr (mean +/- SD). Total renin did not change during ovarian stimulation but it increased to 46 +/- 16 ng/ml per hr (P less than 0.05) 1 or 2 days later, just before hCG administration. Thirty-six hours after hCG administration, just before laparoscopy and egg retrieval, total renin was 123 +/- 97 ng/ml per hr; a peak of 182 +/- 143 ng/ml per hr occurred 2-6 days later--i.e., during the luteal phase of the menstrual cycle. In eight of the patients who did not conceive, total renin returned to baseline 14 days after hCG administration. In four who conceived, a nadir was reached (57 +/- 13 ng/ml per hr) 8-12 days after hCG administration and then total renin increased again as the plasma beta hCG measurement began to rise. By day 16 it averaged 225 +/- 157 ng/ml per hr. In a second group of five patients active renin and prorenin were measured separately. Active renin comprised less than 20% of the total renin at all times. It was unchanged until day 4 after hCG administration and then increased significantly only when plasma progesterone was high. Thus, the initial response to hCG was entirely due to an increase in prorenin. A highly significant correlation was observed between the number of follicles and the total renin increases on the day of aspiration (r = 0.93, P less than 0.001) and at the peak (r = 0.89, P less than 0.001). After hCG administration, a temporal relationship was observed between the rise in total renin and plasma estradiol and progesterone levels. These results demonstrate that plasma prorenin increases markedly after administration of hCG and that the rise is directly related to the number of ovarian follicles and to plasma estrogen and progesterone levels. The findings suggest that prorenin is produced by the mature ovarian follicle and by the corpus luteum in response to gonadotropin stimulation.

Ovarian prorenin

We review here recent evidence that the ovaries synthesize and secrete prorenin and we explore the possible reasons why prorenin, and not active renin, is formed almost exclusively in this extra-renal site. Very high concentrations of prorenin are present in the human ovary in the fluid inside mature follicles. This ovarian prorenin appears to be secreted into the circulation since plasma prorenin increases in normal women for two to three days at mid-menstrual cycle, at the time of ovulation. No change in plasma active renin occurs at this time. Plasma prorenin increases much more at mid-cycle in women whose ovaries have been hyperstimulated with gonadotropins. Their mid-cycle increment in plasma prorenin (after hCG) is directly related to the number of ovarian follicles. Plasma prorenin also increases markedly (10-fold) in pregnant women within two weeks after conception, in parallel with the rise in endogenous hCG. The ovaries are the apparent source of the increase in plasma prorenin during pregnancy since no such increase occurred in a woman with ovarian failure who conceived after receiving a donor egg. These results suggest that the ovaries synthesize and secrete prorenin in response to stimulation by gonadotropic hormones. Future studies will investigate the potential role of ovarian prorenin in human reproductive function. We postulate the existence of a prorenin receptor which activates prorenin and, in consequence, activates a local renin-angiotensin system. The functioning of this system may be regulated by changes in prorenin and its receptor.

Prorenin as a reproductive hormone. New form of the renin system

Prorenin, the biosynthetic precursor of renin, is synthesized by the kidneys. Herein is reviewed recent evidence that the ovaries also secrete prorenin. It was found that prorenin is present in mature human ovarian follicular fluid in extremely high concentrations and that plasma prorenin levels increase transiently in blood during the menstrual cycle at the time of ovulation. No change in plasma active renin levels occurs at this time. Plasma prorenin level also increases 10-fold in pregnant women very soon after conception. The ovaries are apparently the source of this rise, since plasma prorenin levels did not increase in a pregnant woman with ovarian failure who received a donor egg. All of these changes in plasma prorenin levels appear to be caused by gonadotropic hormones. These results suggest a role for ovarian prorenin in human reproductive function. They may have relevance to studies of female infertility, birth control, and toxemia of pregnancy. They also suggest that a renin system exists that is regulated by changes in prorenin.

Cyclical secretion of prorenin during the menstrual cycle: synchronization with luteinizing hormone and progesterone

Plasma prorenin, a high molecular weight precursor form of renin, (renin, EC 3.4.23.15; old number, EC 3.4.99.19), was measured three times weekly in normal young women during the menstrual cycle and was related to changes in luteinizing hormone, estradiol, and progesterone. In all subjects a stable baseline level of prorenin occurred during the follicular phase. Then, simultaneously or soon after the luteinizing hormone peak, plasma prorenin consistently increased about 2-fold. Baseline prorenin ranged from 18 to 40 ng per ml per hr, and peak prorenin ranged from 35 to 65 ng per ml per hr. The maximum increase in prorenin averaged 80%. Prorenin remained elevated during the mid-luteal phase of the menstrual cycle and returned to baseline during the late-luteal phase in coordination with the decrease in progesterone. The changes in prorenin were not synchronized with changes in active renin which was significantly increased only during the mid-luteal phase. These findings suggest that prorenin may be involved in reproductive physiology.

Plasma prorenin in first-trimester pregnancy: relationship to changes in human chorionic gonadotropin

Prorenin and human chorionic gonadotropin are both synthesized in chorionic cells. The relationship of changes in maternal plasma prorenin to changes in human chorionic gonadotropin were therefore evaluated during the first trimester. In samples submitted to the routine chemistry laboratory for detection of pregnancy a positive relationship was observed between prorenin and beta human chorionic gonadotropin during the 5 weeks following conception. Subsequently human chorionic gonadotropin continued to rise but prorenin had reached a plateau. Serial studies in one subject demonstrated that prorenin had increased to 65% of maximum by the thirteenth day following conception whereas human chorionic gonadotropin had risen to only 0.2% of maximum. By 3 to 5 days post partum, beta human chorionic gonadotropin had fallen by 98% but prorenin had fallen by only 50%. The early rise in prorenin following conception and the relatively slow fall post partum suggest that pregnancy-related changes in maternal plasma prorenin are of maternal, not fetal, origin.

Relationship between plasma renin activity and physical fitness in normal subjects

The relationship between plasma renin activity (PRA) at rest and physical fitness was studied in 40 normal young subjects on a liberal sodium intake. Plasma renin activity was measured in arterial blood withdrawn at the end of a 30-min period of rest in recumbency, while physical fitness was expressed by the highest oxygen uptake achieved during an uninterrupted graded exercise test performed in the sitting position on an electromagnetically braked ergometer bicycle (peak VO2). Log PRA correlated significantly and inversely with peak VO2 adjusted for body weight (r = -0.34; P less than 0.05) in single regression analysis. Using multiple regression and adjusted peak VO2, age, urinary sodium excretion and mean intra-arterial pressure as independent variables, no combination of two or more independent variables yielded significant partial correlation coefficients with log PRA. This correlation suggests that PRA at rest is inversely related to the subject's physical fitness.

Effect of ageing on circadian rhythms of plasma renin and aldosterone in mesor-hypertensive women

This study investigated the changes in circadian rhythms of plasma renin activity (PRA) and plasma aldosterone (PA) which occur in essential mesor-hypertensive women, increasing in age. Systemic blood samples were taken throughout a 12 h period from both mesor-hypertensive women and clinically healthy women (control). The women in each group were either post-menopausal or had normal menstrual cycles. A cosinor method of temporal series was the analysis employed to compute the properties of PRA and PA circadian rhythms. The clearest effect of ageing, recorded in essential mesor-hypertensive women, is a decrease in circadian mesor of PRA cycle (P = 0.002). The age-related changes in clinically healthy women appear to be more extensive and involve a decrease for both mesor (P less than 0.001) and amplitude (P = 0.007) of PRA circadian rhythm. These disparities are convincing evidence for a non-physiological decline of the RAAS rhythmic function in the aged essential mesor-hypertensive women. The lack of an age-associated decrease in circadian PRA amplitude merits and pathophysiological and clinical investigation because it is a possible risk factor for post-menopausal, essential mesor-hypertensive women.

Premenstrual syndrome

The premenstrual syndrome (PMS) is a major clinical entity afflicting a large segment of the female population. Available information are descriptive in nature and the etiology of this syndrome remains unclear. In this review, both biochemical and psychosocial elements of the syndrome have been explored in an effort to redefine the pathophysiology of this seemingly multifactorial psychoneuroendocrine dysfunction. We propose that luteal phase sensitivity to and subsequent withdrawal from the central effects of the neuropeptides beta-endorphin and alpha-melanocyte-stimulating hormone result in a cascade of neuroendocrine changes within the brain-hypothalamus-pituitary complex. Modulation of neurotransmitter function by these peptides may produce alterations in mood and behavior as well as enhance pituitary release of prolactin and vasopressin. Variable gonadal steroid modulation of these responses from subject to subject likely accounts for the heterogeneous clinical manifestations of the PMS.

Differences and similarities among circadian characteristics of plasma renin activity in healthy young women in Japan and the United States

A circadian rhythm of plasma activity (PRA) was demonstrated for both Japanese and North American women, the latter mostly Caucasians of mixed ethnic origin. The results were based on blood samples withdrawn at 4-hour intervals during a 24-hour span (in March 1978) from 20 subjects from Fukuoka (average age 20.4 +/- 0.1 years) and 16 subjects from Minneapolis (average age 20.2 +/- 0.4 years). The rhythms in the two populations showed similarities in some characteristics and differences in others. The timing of high values, i.e., of acrophases, objectively assessed by curve-fitting (and of corresponding 95 per cent confidence limits) was at 07(36) (05(00), 10(16) and 06(32) (03(00), 10(00) for Japan and USA, respectively. As objective measures of the extent of predictable rhythmic change mean amplitudes, in nanograms per milliliter per hour (ng/ml/hour), were similar (0.31 and 0.32); a statistically significant difference (P less than 0.05) was found in mean amplitudes expressed as percentage of the rhythm-adjusted average. Mean rhythm-adjusted average values (mesors) were lower in women from Japan than in those from the United States: (1.64 +/- 0.14 and 2.39 +/- 0.23 ng/ml/hour, respectively; P less than 0.01). A statistically significant difference in dietary salt, indicated by differences between the Japanese and North American women in the urinary excretion of sodium and chloride (P less than 0.05), almost certainly contributed to these results.

Sequential changes in the human renin-angiotensin system following therapeutic termination of pregnancy

Plasma renin and angiotensin II levels were measured in nine patients immediately before and at half-hourly intervals in the four hours following therapeutic termination of pregnancy. There was a small fall in renin and angiotensin II levels over the first 1 to 2 hours, followed by a slight increase. The magnitude of these effects was much smaller than those previously seen following normal delivery. It is concluded that in early pregnancy maternal, rather than feto-placental, factors are controlling the renin-angiotensin system.

Treatment of premenstrual syndrome by spironolactone

Spironlactone was given to 28 women in a double blind cross over trial during four menstrual cycles. Hormonal profiles were measured during the first two cycles. Plasma aldosterone was elevated in the premenstrual phase of the cycles but there was no significant difference between symptomatic and asymptomatic groups. The rise in serum progesterone was higher in the symptomatic group during the postovulatory phase. The administration of spironolactone reduced weight and relieved psychological symptoms in more than 80 per cent of the symptomatic group.

Plasma renin activity and plasma aldosterone during the normal menstrual cycle

Six normal women were studied under metabolic balance conditions during the menstrual cycle. Plasma renin activity (PRA) and plasma aldosterone were estimated throughout the cycle under standardized, uniform conditions with sensitive radioimmunoassays. There is a linear increase in PRA and plasma aldosterone during the luteal phase of the cycle provided ovulation occurs. If ovulation fails, no rise is seen in either parameter. Thus, a functioning corpus luteum seems to be essential for the production of these hormonal changes.

Monoamines and ovarian hormone-linked sexual and emotional changes: A review

Emotional upsets related to changes in ovarian hormones are highly prevalent and are responsible for psychiatric morbidity and mortality. Significant increases in acute psychiatric hospitalizations, suicidal activity, and other psychopathology occur during the premenstruum and during menstruation. This paper reviews evidence indicating that menstrual cycle psychopathology may be mediated by the effects of estrogen, progesterone, and possibly the renin-angiotensin-aldosterone system on the brain monoamines, norepinephrine, dopamine, and serotonin. During the menstrual cycle, psychopathology often begins with the onset of luteal estrogen-progesterone-angiotensin-aldosterone secretion and intensifies as these hormone levels later fall, prior to and during menstruation. Aldosterone is reported elevated in cases of premenstrual tension syndrome. There are numerous reports of affective upsets occurring with the use of estrogen-progestin oral contraceptives and following their withdrawal. Contraceptives stimulate the renin-angiotensin-aldosterone system and are reported useful in alleviating premenstrual-menstrual emotional upsets and postpartum depressive episodes. Affective lability, prevalent at parturition, occurs when estrogen, progesterone, and aldosterone levels are first high and later falling. Exogenous estrogen and progesterone profoundly affect mating activity in castrated rhesus monkeys, and cyclic fluctuations in sexual activity in humans may occur during the menstrual cycle. Much information links manic and depressive reactions with alterations in brain monoamines. Lithium, monoamine oxidase inhibitors, and tricylic antidepressants, specifically used to treat affective disorders, are reported useful in treating ovarian hormone-linked upsets. Similarities exist between changes in animal behavior caused by drugs altering affective states and the effects of ovarian hormones. Like certain antidepressants, estrogen induces hyperactivity in rats. Like reserpine, progesterone exhibits sedative and soporific effects. Sexual behavior in female rats is reported linked to changes in brain monoamines. Agents increasing brain monoamine levels and availability decrease mating responses, and monoamine depletors, such as reserpine may be substituted for progesterone in activating mating behavior. Serotonin and dopamine appear to be important in the regulation of ovulation. Brain norepinephrine varies with the phases of the rat estrus cycle. Castration increases brain norepinephrine and decreases brain dopamine. Exogenous estrogen decreases rat brain norepinephrine content. The monoamine-destroying enzymes, monoamine oxidase, and catechol O-methyl transferase are affected by ovarian steroids and show fluctuating levels during the reproductive cycle. The effects of reserpine, monoamine oxidase inhibitors, tricyclic antidepressants, and lithium on monoamines in neurophysiological preparations have been used as evidence supporting theories linking monoamine changes with human affective disorders. Estrogen, progesterone, and angiotensin also exhibit effects on in vitromonoamine systems. Like the tricyclic antidepressants, uptake of norepinephrine and dopamine by nerve endings is inhibited in the presence of estrogen, progesterone, and angiotensin. As with reserpine, the flow of these monoamines from nerve endings is increased by progesterone. Estrogen slows the flow of norepinephrine from nerve endings and decreases the electrically induced release of serotonin and norepinephrine from brain slices. The above information provides clues that ovarian hormone-linked psychopathology, like affective disorders in general, may be related to alterations in brain monoamines.

Variations in mucosal water and sodium transfer associated with the rat oestrous cycle

1. Mucosal water and sodium transfer were measured in everted sacs of rat jejunum.2. Mucosal water transfer was higher at pro-oestrus and oestrus than at metoestrus and dioestrus.3. Injection of 10 mug aldosterone I.P. 28 hr before the experiment produced a stimulation of mucosal water and sodium transfer in sacs prepared from rats at dioestrus but not in sacs from rats at oestrus.4. A significant increase in mucosal water and sodium transfer was observed when sacs from dioestrous rats were incubated with angiotensin at a concentration of 10(-9) g/ml. No effect was obtained in sacs from oestrous rats.5. Treatment of adrenalectomized-ovariectomized rats with oestradiol caused a stimulation of mucosal water transfer 28 hr after injection.6. It is suggested that the actions of ovarian steroids on water and electrolyte metabolism might be due to increased activity of both the adrenal cortex and the renin-angiotensin system.

Renin, angiotensin and aldosterone in human pregnancy and the menstrual cycle

Aldosterone secretion is frequently, although not invariably, increased above the normal non-pregnant range in normal pregnancy. Substantial increases in plasma aldosterone concentration have also been demonstrated as early as the sixteenth week. In pregnancy, aldosterone secretion rate responds in the usual way to changes in sodium intake.

Plasma renin concentration is frequently, but not invariably, raised above the normal non-pregnant range. Plasma renin-substrate is consistently raised in pregnancy. Plasma angiotensin II has also been shown usually to be raised in a series of pregnant women.

A significant positive correlation has been shown between the maternal plasma aldosterone concentration and the product of the concurrent plasma renin and renin-substrate concentrations. This suggests that the increased plasma aldosterone in pregnancy is the consequence of an increase in circulating angiotensin II, which in turn is related to the level of both renin and its substrate in maternal blood. For these reasons, estimations of renin activity in pregnancy are of dubious value.

The increased renin, angiotensin and aldosterone concentrations may represent a tendency to maternal sodium depletion, probably mainly a consequence of the increased glomerular filtration rate. It is possible that the nausea and other symptoms of early pregnancy may be a consequence of this tendency to sodium depletion, with its attendant hormonal changes. In ‘pre-eclampsia’, renin and aldosterone values are generally slightly lower than in normal pregnancy. Human chorion can apparently synthesize renin independently of the kidney. The physiological significance of this remains at present obscure, but it seems unlikely that this source contributes much, if at all, to the often elevated maternal plasma renin.

Plasma renin, renin-activity and angiotensin II concentrations, and aldosterone secretion are increased in the luteal phase of the menstrual cycle.

Functional correlates of plasma renin activity in hypertensive patients

Correlates of peripheral plasma renin activity were studied in 31 normotensive subjects and 93 untreated hypertensive patients. The latter were grouped according to apparent type of hypertension: essential (58), renovascular (21), renal parenchymal disease (11), and primary aldosteronism (3). Plasma renin activity was inversely correlated with total blood and plasma volumes in normal men, men with essential hypertension, and patients with renal arterial stenosis; no correlations were found in normal and essential hypertensive women and patients with renal parenchymal disease. Serum sodium and potassium concentrations were significantly and inversely related to renin activity only in renovascular hypertension and not in the other hypertensive or normal groups. Relationships of plasma renin activity to arterial pressure and other hemodynamic functions were studied in hypertensive patients. Only in the renovascular group did diastolic pressure correlate positively and significantly, indicating participaton of the renal pressor system in this form of hypertension throughout a wide range of pressures. Cardiac index and left ventricular ejection rate were directly related to renin activity in essential hypertensive men and patients with renal arterial and parenchymal diseases. The data show that plasma renin activity in hypertensive patients should not be judged alone but along with factors modifying it.

The effect of acute haemorrhage in the dog and man on plasma-renin concentration

1. The effect of acute haemorrhage on the plasma renin concentration was studied in the dog and man.2. Plasma-renin concentration was regularly increased after the larger bleeds; after the smaller haemorrhages plasma-renin concentration remained unchanged.3. The results are discussed in relation to current hypotheses concerning the control of renin and aldosterone secretion.