ovarian-hyperstimulated women: Correlation with the number

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1 Pro. Natl. Aad. Si. USA Vol. 84, pp , Otober 1987 Medial Sienes Plasma prorenin response to human horioni gonadotropin in ovarian-hyperstimulated women: Correlation with the number of ovarian folliles and steroid hormone onentrations (estradiol/progesterone/renin/ovary) JOSEPH ITSKOVITZ*t, JEAN E. SEALEYt, NICOLA GLORIOSOt, AND ZEV ROSENWAKS* *Jones Institute for Reprodutive Mediine, Department of Obstetris and Gyneology, Eastern Virginia Medial Shool, Norfolk, VA 2357; and tcardiovasular Center, The New York Hospital-Cornell University Medial College, New York, NY 121 Communiated by Alexander G. Bearn, June 18, 1987 (reeived for review November 24, 1986) ABSTRACT Plasma prorenin and ative renin were measured before and after human horioni gonadotropin () administration in two groups of patients undergoing ovarian stimulation for 4-6 days with follile-stimulating hormone alone or in ombination with luteinizing hormone, for in vitro fertilization. Baseline total plasma renin (prorenin plus ative renin; n = 12) averaged 25 ± 8 ng/ml per hr (mean ± SD). Total renin did not hange during ovarian stimulation but it inreased to 46 ± 16 ng/ml per hr (P <.5) 1 or 2 days later, just before administration. Thirty-six hours after administration, just before laparosopy and egg retrieval, total renin was 123 ± 97 ng/ml per hr; a peak of 182 ± 143 ng/ml per hr ourred 2-6 days later-i.e., during the luteal phase of the menstrual yle. In eight of the patients who did not oneive, total renin returned to baseline 14 days after administration. In four who oneived, a nadir was reahed ( ng/ml per hr) 8-12 days after administration and then total renin inreased again as the plasma. measurement began to rise. By day 16 it averaged 225 ± 157 ng/ml per hr. In a seond group of five patients ative renin and prorenin were measured separately. Ative renin omprised <2% of the total renin at all times. It was unhanged until day 4 after administration and then inreased signifiantly only when plasma progesterone was high. Thus, the initial response to was entirely due to an inrease in prorenin. A highly signifiant orrelation was observed between the number of folliles and the total renin inreases on the day of aspiration (r =.93, P <.1) and at the peak (r =.89, P <.1). After administration, a temporal relationship was observed between the rise in total renin and plasma estradiol and progesterone levels. These results demonstrate that plasma prorenin inreases markedly after administration of and that the rise is diretly related to the number of ovarian folliles and to plasma estrogen and progesterone levels. The findings suggest that prorenin is produed by the mature ovarian follile and by the orpus luteum in response to gonadotropin stimulation. The renin-angiotensin system plays a key role in blood pressure, fluid and eletrolyte homeostasis through the vasoonstritor ation of angiotensin II, and the stimulation of aldosterone biosynthesis by the adrenal zona glomerulosa ells (1). Ative renin is synthesized by and sereted from the kidney. Prorenin, its enzymatially inative preursor, irulates at higher onentrations than ative renin (2) and is also mostly derived from the kidneys. Nonetheless, it persists at low levels in the blood of hronially nephretomized females and males (3-5). Prorenin is also synthesized by the plaenta (6-8) and is markedly inreased in the plasma of The publiation osts of this artile were defrayed in part by page harge payment. This artile must therefore be hereby marked "advertisement" in aordane with 18 U.S.C solely to indiate this fat. pregnant women (9-12). However, the early pregnanyrelated rise in plasma prorenin is apparently not due to plaental seretion sine it did not our in a patient with ovarian failure (13). Reent evidene suggests that prorenin (13-18) and the renin-angiotensin system (14, 19, 2) may be linked to ovarian physiology. Mature human ovarian folliles ontain prorenin in high onentrations (14, 18); only 1% is enzymatially ative (14). Plasma prorenin, but not ative renin, inreases at midmenstrual yle just after the luteinizing hormone (LH) surge (15, 16) and a seond but lower rise in prorenin, together with ative renin, ours later (15) when progesterone is high. Ovarian hyperstimulation with gonadotropins results in the development of multiple folliles and onsequently many orpora lutea. Preliminary studies suggest that suh patients have a marked rise in prorenin in response to human horioni gonadotropin () (13, 14, 17). We therefore examined the relationship of the -indued inrease in prorenin to the number of folliles indued by ovarian stimulation and to the hanges in plasma estradiol and progesterone that ourred in patients undergoing folliular aspiration for in vitro fertilization and embryo transfer. METHODS Patients. Two groups of patients undergoing ovarian stimulation for in vitro fertilization and embryo transfer were studied. Group A onsisted of 12 patients in whom serum samples for routine hormonal measurements were retrospetively analyzed. We seleted patients in whom both ovaries had been ompletely available for folliular aspiration. Ten patients had irreparable tubal disease and in 2 patients the ause of infertility was unknown. Ovarian stimulation was aomplished as reported (21-24). Seven patients were treated with "pure" follile-stimulating hormone (FSH) [Metrodin, Serono Laboratories (Randolph, MA), ontaining 75 international units (IU) of human urinary FSH and <1 IU of LH in eah ampule] and 5 patients were treated with a ombination of "pure" FSH and human menopausal gonadotropin (HMG) (Pergonal, Serono Laboratories, ontaining 75 IU of FSH and 75 IU of LH). In the FSH-only protool, four ampules of FSH were injeted on days 3 and 4 of the menstrual yle; this was followed by injetion of two ampules of FSH on subsequent days. In the FSH/HMG Abbreviations:, human horioni gonadotropin; FSH, follilestimulating hormone; LH, luteinizing hormone; HMG, human menopausal gonadotropin; IU, international units. Present address: Department of Obstetris and Gyneology, Rambam Medial Center, Haifa, Israel. Present address: Clinia Media Generale, Centro Ipertensione, University di Sassari, 71 Sassari, Italy. To whom reprint requests should be addressed. 7285

2 7286 Medial Sienes: Itskovitz et al. protool, two ampules of FSH and two ampules of HMG were injeted on days 3 and 4 of the yle; this was followed by injetion of two ampules of HMG on subsequent days. After 5-7 days of treatment, (1, IU) was injeted as a surrogate LH surge (defined as day ). was administered hr following the last injetion of gonadotropins (FSH or HMG). Folliles were aspirated by laparosopy under general anesthesia about 36 hr later (day 2). All visible folliles were aspirated and the maturation of the ooytes and the granulosa ells from eah follile was determined (24). In vitro fertilization of the ooytes and embryo ulture were aomplished as reported (24). Starting on day 3, patients were treated with intramusular injetion of progesterone, 25 mg/day, and embryos were transferred to the uterus on day 4. Group B onsisted of five patients studied prospetively in whom plasma samples instead of serum samples were olleted so that hanges in ative renin ould be examined. Four patients had irreparable tubal disease and in one patient the ause of infertility was related to male fator. Three patients were treated with FSH only and two patients were treated with a ombination of FSH/HMG. Protools similar to those desribed for patients in group A were employed. At laparosopy both ovaries were found to be ompletely available in three patients. However, in two patients only about 7% of the ovarian surfae was available for aspiration. Blood Colletion and Proessing. Serum samples (group A) or plasma samples (group B) were olleted daily at 8-9 a.m. until day 2 and on alternate days thereafter. On the day of laparosopy blood samples were withdrawn 15 min before the indution of anesthesia. The serum samples from group A were frozen and thawed several times for routine hormonal measurements, whih aused ryoativation of prorenin and falsely high ative renin values (2). For this reason only total renin values are reported in group A patients. For group B, blood was olleted into K2EDTA Vautainers and maintained at room temperature until the plasma was separated. Ative renin was usually measured after only one freezing and thawing yle; however, samples that were olleted 6 or more days following administration (see below) were exposed to two freezing and thawing yles. (From day 6, samples were mailed by the patients to Norfolk on dry ie.) Pro. Natl. Aad. Si. USA 84 (1987) Hormonal Measurements. Prorenin in serum or plasma was onverted to ative renin by limited proteolysis with Sepharose-bound trypsin, as desribed (15). Ative renin was measured by enzymati assay utilizing endogenous plasma renin substrate (25). For serum samples, 3 mm EDTA was added before the enzymati assay to inhibit angiotensinases and onverting enzyme. The angiotensin I formed during the enzymati assay was measured by RIA (25). Plasma prorenin was alulated as the differene between the endogenous ative renin and the total renin measured after trypsin ativation. Results are expressed as the rate of angiotensin I formation (ng/ml per hr). Serum estradiol and progesterone were assayed using a ommerially available RIA kit (Pantex, Santa Barbara, CA), as reported (22). Statistial Analysis. The signifiane of hanges in hormone levels during the yle was alulated by using the paired Student's t test with Bonferroni's orretion for multiple measurements (26). Correlations between total renin and number of folliles were determined by regression analysis. P <.5 was onsidered to be signifiant. RESULTS Group A. At laparosopy 1.6 ± 5.6 folliles (mean ± SD; range, 3-2) were aspirated and mature granulosa ells were deteted in 88.6% ± 1.1% (range, %) of the aspirated folliles (24). Total renin levels. The total renin results from two of these patients were reported in a short preliminary ommuniation (13). Baseline total serum renin (day 3 of menstrual yle) was 25 ± 8 ng/ml per hr (mean ± SD); it remained relatively stable during the administration of FSH and FSH/LH in the folliular phase (Fig. 1). A small but onsistent inrease was observed on the day of injetion (day ) before was administered (P <.5) (Fig. 1 and Table 1). Following injetion a marked and sustained inrease in total renin was observed. Just before folliular aspiration (day 2) it had risen to 6.4-fold baseline (range, ) and it further inreased slightly to reah a peak of 9.-fold baseline (range, ), either on day 4 (n = 5), day 6 (n = 6), or day 8 (n = 1). (See Fig. 2 for an illustration of the spetrum of responses.) Thus, the highest level of total renin ourred after follile aspiration-that is, during the luteal phase of the yle. In the eight 24 r t.2 I.C_ T I- a} 2 F 16K 2~ 8 4K r5 uays I E -. w C3 CL - 4 CL n -i o FIG. 1. Serum total renin, estradiol, and progesterone hanges (mean ± SEM) in 12 patients undergoing ovarian stimulation with gonadotropins and. Baseline is the third day after the beginning of menstruation. was administered on day and ovarian folliles were aspirated on day 2 after blood sampling. Total serum renin was signifiantly higher than baseline on day (P <.5) and was almost bak to baseline on day 14 in 8 patients who did not oneive. In 4 pregnant women total renin inreased again after day 1. Estradiol was above baseline (P <.5 or greater) from day -4 until day 12. Progesterone was above baseline on day 1 and thereafter. The shaded area represents the estimated level of serum progesterone (based on the level of progesterone on day 14 in the nonpregnant patients) aused by the administration of exogenous progesterone (25 mg/day), whih was given from day 3 until day 14. The serum estradiol and progesterone values after day 1 are from the 8 nonpregnant women. 4 2 u) '

3 Table 1. Total serum renin and progesterone before (-) and after (+) injetion Total renin, Progesterone, Day ng/ml per hr ng/ml Baseline* 25 ± 8.7 ± ± 12.8 ±.3 46 ± 16t 1.3 ± ± 23t 3.8 ±.3t ± 97t 5.1 ± 3.6t Data are expressed as mean ± SD (n = 12). *Baseline = day 3 of the menstrual yle. tp <.5 ompared to baseline levels. patients who did not oneive, total renin had fallen to 132% of baseline level on day 14 and they had undetetable levels. In the four women who oneived, total renin reahed a nadir on days 8-12 (57 ± 13 ng/ml per hr) and then inreased to 225 ± 157 ng/ml per hr on day 16 (Fig. 1), when was 424 ± 293 miu/ml. Magnitude of inrease in total renin in relation to the number of ovarian folliles. Analysis of the relationships between the inrease in total serum renin and the number of aspirated folliles on day 2 dislosed a highly signifiant orrelation (r =.93, P <.1, Fig. 3A). A somewhat weaker orrelation (r =.73, P <.1) was observed on day 1 (8-12 hr after injetion). Total renin was also higher than baseline on day but the relationship to the number of folliles was not signifiant (r =.32). The maximum inrease in total renin after administration ourred during the luteal phase and the peak value in eah subjet was highly related to the number of folliles (r =.89, P <.1, Fig. 3B). Fig. 2 illustrates the hanges in serum total renin in representative individual subjets with low, intermediate, or high numbers of folliles. For omparison, the levels of total plasma renin throughout a representative natural yle are also illustrated (16). Temporal relationship between blood levels of total renin, estradiol, and progesterone. Estradiol inreased during the folliular phase during the period of ovarian stimulation by gonadotropins; estradiol fell after injetion and fell further after folliular aspiration, but rose again during the luteal phase (Fig. 1). The number of folliles orrelated with plasma estradiol on day (r =.84, P <.1), day 1 (r =.89, P <.1), and day 2 (r =.87, P <.1) (Fig. 3C). Not surprisingly, a signifiant orrelation between estradiol and total renin was also demonstrated (Fig. 3D). Baseline progesterone level (day 3 of the menstrual yle) was.7 ±.3 I-I C7 'S.CC Medial Sienes: Itskovitz et al. 2 folliles 11 folliles,,, 1, Days 4 folliles t ncu natural yle LH Surge FIG. 2. Total serum renin levels throughout the stimulated yles of three representative patients with different numbers of ovarian folliles. Shown for omparison are the hanges in total plasma renin throughout a natural yle (16) in whih only one follile usually matures. Pro. Natl. Aad. Si. USA 84 (1987) 7287 ng/ml; it inreased slightly on day (Fig. 1 and Table 1). Following a peak of >8 ng/ml on day 8, progesterone fell to about 2 ng/ml on days 12 and 14. The hormonal level on days 12 and 14 was largely due to the daily injetion of exogenous progesterone and so the orpora lutea were apparently ontributing an average of 6 ng of progesterone per ml at the peak. Total serum renin dislosed a temporal relationship with serum progesterone levels through the folliular and the luteal phases and with estradiol levels during the luteal phase. However, the rise and fall of both serum estradiol and progesterone during the luteal phase were preeded by the rise and fall of total serum renin (Fig. 1 and Table 1). Group B. In this seond prospetively studied group of patients, 8.2 ± 2.2 (range, 6-11) folliles per patient were aspirated and 73.2% ± 16.4% (range, %) were lassified as mature folliles. The hanges in plasma prorenin, ative renin, and progesterone are shown in Fig. 4. Baseline plasma ative renin was 1.9 ± 1.1 ng/ml per hr (mean ± SD); unlike plasma prorenin, ative renin remained unhanged until day 6 after administration. On day 6 and thereafter, ative renin levels inreased signifiantly (P <.1), at a time when plasma prorenin was falling and plasma progesterone was at peak levels. Ative renin omprised only 8% ± 2% of total renin under baseline onditions and was 11% ± 6%, 4% ± 3%, 5% ± 1%, and 11% ± 4% on days, 2, 6, and 8, respetively. The pattern of hange in plasma prorenin resembled that of total plasma renin in group A (Fig. 1). The lak ofa further inrease in plasma prorenin from day 2 to day 4 in this group may be related to the fat that in two patients plasma samples from day 4 were not available for analysis. These two patients had the highest prorenin levels on day 2 (25 and 127 ng/ml per hr). DISCUSSION The present results demonstrate that administration following ovarian hyperstimulation with gonadotropins results in marked and sustained inreases in irulating prorenin. The levels ahieved are muh higher than those that our normally during the spontaneous LH surge of a natural yle. As in natural yles, ative plasma renin was essentially unhanged until the luteal phase. The height of the irulating prorenin response to was diretly related to the number of mature folliles deteted at the time of aspiration, suggesting that prorenin is produed and sereted by the ovarian folliles. Furthermore, a temporal relationship between plasma prorenin and orpus luteum steroidogeni ativity was also demonstrated. Relationship of Prorenin Levels to the Number of Mature Folliles. During the folliular phase of the menstrual yle only one follile normally matures and ovulates, and plasma prorenin inreases an average of 9% after the LH surge for about 2 days (16). In stimulated yles there was a greater response of prorenin, the magnitude of whih was diretly related to the number of folliles. The highest prorenin levels seen in nonpregnant women (586 ng/ml per hr, 21-fold baseline) ourred in a patient who had 2 folliles. The average inrease in prorenin per follile (46% on day 2 and 63% on day 6) was similar to that that ours after the spontaneous LH surge (16). This suggests that the high plasma prorenin levels after ovarian stimulation are due to the presene of multiple folliles and not to abnormally high prorenin seretion by individual folliles. Any small folliles that were not ounted either ontributed little to irulating levels of prorenin or were proportional to the number of mature folliles. The highly signifiant orrelation between the plasma prorenin onentration during the luteal phase and the number of folliles suggests that prorenin was sereted by the orpora lutea that were formed from the folliles.

4 7288 Medial Sienes: Itskovitz et al. Pro. Natl. Aad. Si. USA 84 (1987) B 28 ' 24 E 48 'J R=.93 =. 2 P<.1 _ 4 16 > 32 _ a ' 12 ~~~~~~~~~~~~~~~~~~~~~~~~I 56r. R =.89 p <. I T a 4 i Number of folliles Number of folliles FIG. 3. (A) Relationship between the hange in total serum C renin and the number of folliles on day of ovarian follile aspiration (day 2). (B) Relationship m -5 between the maximal hange in J total serum renin in the luteal "I ('a -5 E phase and the number of ovarian H5 folliles. (C) Relationship between serum estradiol levels on z To the day of aspiration (day 2) and the number of folliles. (D) Relationship between the hange in >w total serum renin and serum estradiol levels on the day of ovarian follile aspiration (day Number of folliles Estradiol day 2 (pg/ml) 2). Time Course of Prorenin and Ative Renin Responses. return to baseline until days This prolonged response Plasma prorenin does not inrease during natural menstrual is most probably related to the longer half-life of (-'32 yles before the LH surge (15, 16). In ontrast, a small but hr) ompared to LH (':1 hr) (28). The sensitivity of the orpus signifiant inrease in prorenin was deteted on day, before luteum to is also refleted in the preipitous rise of the injetion, in the stimulated patients. This rise prorenin after day 12 in the pregnant women (present study ourred whether the patients had been stimulated with FSH and ref. 13). alone or with a ombination of FSH/LH and was therefore That the initial inrease in prorenin after administration is not assoiated with an inrease in ative renin has been not due to the exogenously administered LH. A spontaneous LH surge does not usually our in hyperstimulated women learly demonstrated in this study. The prorenin rise after the (27). Presumably, the growing follile normally seretes small LH surge in the natural yle is also not assoiated with a amounts of prorenin, but the seretion of prorenin only signifiant rise in ative renin (15, 16). However, both in inreases enough to be detetable when multiple folliles natural yles (15, 29) and in this study, ative renin inreased during the luteal phase when progesterone was high. develop. In the natural menstrual yle the peak of prorenin is This response ould be related to the natriureti effet of sustained for about 1 day after the LH surge (16). In ontrast, progesterone (29) and therefore be of renal origin (Fig. 4). injetion in stimulated women aused a sustained Alternatively, it may be the result of in vitro ryoativation inrease in prorenin that peaked on days 4-6 and did not of prorenin (only samples olleted during the luteal phase 2r- 11 o 16 8 _E E 'S-1 vi ' bl 12 6 Proreni r ) O 8 4._) ), C U) --a_ 4F-,! Ative renin 2) 2 o2 a- L Baseline Days FIG. 4. Plasma prorenin, ative renin, and progesterone levels (mean + SEM) throughout the yle in five patients treated with gonadotropins and. Patients were treated with progesterone (25 mg/day) from day 3 through day 14.

5 Medial Sienes: Itskovitz et al. were frozen and thawed twie and also delivered on dry ie to Norfolk). Temporal Relationship Between Prorenin and Ovarian Hormones Level. Estradiol is the primary hormone sereted by the granulosa ells of the preovulatory follile (3-32). Ovarian stimulation was assoiated with an augmented inrease in plasma estradiol during the folliular phase that orrelated with the number of folliles. A signifiant orrelation was observed between prorenin and estradiol levels on days 1 and 2 following injetion. It is unlear whether the level of eah hormone is independently related to the number of maturing folliles or whether this orrelation represents a ause and effet relationship. It is possible that estradiol (or its androgen preursors) stimulates ovarian prorenin biosynthesis. Alternatively, loally produed prorenin may affet estrogen levels by ausing alterations in theal/interstitial androgen biosynthesis or metabolism. The transition between preovulatory follile and orpus luteum entails a deline in folliular estrogen biosynthesis and an inrease in progesterone biosynthesis. Examination of the pattern of prorenin and progesterone levels through the stimulated yle dislosed a striking temporal relationship between the two hormones. The prorenin rise preeded the inrease in progesterone. The idea that ovarian prorenin may be a mediator of the LH/-indued transition between preovulatory follile and orpus luteum steroidogeni ativity is attrative and deserves further study. Angiotensin II affets intraellular alium and phosphatidylinositol metabolism (33, 34). Therefore ovarian prorenin, through angiotensin II ation, may be involved in other ovarian endorine events. Putative ations of the ovarian prorenin-renin-angiotensin system inlude ontrol of ovarian blood flow through its effet on vasular smooth musle tone (1) and the angiogeni property of angiotensin II (35). The finding that hanges in plasma prorenin are not aompanied by signifiant hanges in ative renin has led to speulation that prorenin is ativated loally at its site of ation (36). That angiotensin II might be formed loally is supported by the reports that extrarenal renin is found in the same ells as the other omponents of the renin system (37, 38) İn summary, these results are onsistent with the view that ovarian prorenin is produed and sereted by the mature follile and by the orpus luteum in response to stimulation by LH/. Further studies to investigate the role of prorenin in folliular development and orpus luteum funtion are needed. However, the results from the present study suggest that ovarian prorenin may be related to ovarian steroidogeni ativity. We thank Chiara Troffa, M.D., for her assays of prorenin and renin and Linda Stakhouse and Darlene A. Caryl for their seretarial assistane. 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