Low dose human chorionic gonadotropin administration at the time of gonadotropin releasing-hormone agonist trigger versus 35 h later in women at high risk of developing ovarian hyperstimulation syndrome - a prospective randomized double-blind clinical trial.

BACKGROUND: Ovarian hyperstimulation syndrome remains a serious complication during in vitro fertilization cycles if high dose human chorionic gonadotropin (hCG) is used to trigger ovulation in high responder patients. Though much of this risk is mitigated with trigger using gonadotropin releasing-hormone (GnRH) agonist alone, it may result in lower birth rates. GnRH-agonist trigger and adjuvant low dose hCG has been proposed to improve birth rates, but timing of this hCG support to corpus luteum function has never been fully described. In this randomized, prospective trial, we explore differences in live birth rates and incidence of ovarian hyperstimulation syndrome (OHSS) in high-responder patients undergoing in vitro fertilization (IVF) receiving low dose hCG at the time of GnRH-agonist (dual trigger) or hCG adjuvant at the time of oocyte retrieval. Does the timing of hCG support make a difference? RESULTS: Thirty-four subjects high-responder patients were randomized to receive low-dose hCG at the time of GnRH-agonist trigger (Group 1) and 37 received low-dose hCG at the time of oocyte retrieval (Group 2). There were no differences in the baseline characteristics and outcome of ovarian stimulation between the two groups. There were no differences in the live birth rates between Group 1 and Group 2 by intention-to-treat (14/34, 41.2% versus 21/37, 56.8%, p = 0.19) or per-protocol (14/26, 53.8% versus 19/31, 61.3%, p = 0.57) analyses. There was a slightly higher incidence of OHSS in Group 2 compared to Group 1 although the difference was not statistically significant (3/31, 9.7% versus 1/26, 3.8%). All the cases of OHSS in Group 2 were moderate while the one case of OHSS in Group 1 was mild. CONCLUSIONS: For high responder patients receiving GnRH-agonist trigger, low dose hCG supplementation allowed high pregnancy rates after fresh embryo transfer, regardless of whether it was given at the time of trigger or at oocyte retrieval. Dual trigger may be preferable to reduce the risk of OHSS.

Predicting successful induction of oocyte maturation after gonadotropin-releasing hormone agonist (GnRHa) trigger.

STUDY QUESTION: Are there factors predicting the number of total and mature oocytes retrieved after controlled ovarian hyperstimulation (COH) utilizing a gonadotropin-releasing hormone (GnRH) antagonist protocol and a GnRH agonist (GnRHa) to induce oocyte maturation? SUMMARY ANSWER: Peak estradiol (E2) level, post-trigger LH and progesterone and the magnitude of LH rise are independent predictors of the total number of oocytes and mature oocytes retrieved. WHAT IS KNOWN ALREADY: Despite multiple follicular development in high responders, oocyte retrieval after a GnRHa trigger in a small subset of patients fails to obtain a substantial number of total oocytes or mature oocytes. STUDY DESIGN, SIZE AND DURATION: A retrospective chart review of all autologous and oocyte donation cycles utilizing a GnRHa antagonist protocol where GnRHa was used for the induction of oocyte maturation between 1 April 2003 and 31 December 2011. PARTICIPANTS/MATERIALS, SETTING AND METHODS: A total of 508 autologous and donor IVF/ICSI cycles utilizing a GnRH antagonist protocol for COH and GnRHa for the induction of oocyte maturation at a university-based tertiary fertility center. MAIN RESULTS AND THE ROLE OF CHANCE: Peak E2 on the day of trigger (r = 0.19, P < 0.001), post-trigger LH (r = 0.12, P = 0.009) and progesterone (r = 0.47, P < 001) and LH rise (r = 0.18, P < 0.001) all positively correlated with the number of total and mature oocytes retrieved. The true incidence of empty follicle syndrome was 1.4% (7/508). There was no post-trigger LH or progesterone cut-off value for the prediction of oocyte yield. However, all cases of empty follicle syndrome occurred in patients with post-trigger LH <15 IU/l and P ≤ 3.5 ng/ml. The findings of this study may also be due to chance since it was a retrospective study and not prospectively designed. LIMITATION, REASONS FOR CAUTION: This is a retrospective chart review and therefore subject to bias. Serum hormone measurements were performed between 8 and 12 h after GnRHa trigger rather than a standardized time period following trigger administration. Therefore, peak levels of LH may have been missed due to the short ascending limb of LH rise lasting approximately 4 h after GnRHa trigger. WIDER IMPLICATIONS OF THE FINDINGS: The results of this study can be generalized to high responders utilizing a GnRH antagonist protocol for COH and a GnRHa for the induction of oocyte maturation. The use of alternative stimulation regimens or medications will limit the ability to generalize the results of this study to other populations. STUDY FUNDING/COMPETING INTEREST(S): This study was not funded, and there are no conflicts of interest. TRIAL REGISTRATION NUMBER: n/a.

Efficacy of oral micronized progesterone in the treatment of luteal phase defects.

OBJECTIVE: Vaginal progesterone suppositories are an accepted treatment for infertility attributed to luteal phase defects. Although oral micronized progesterone may be preferable to suppositories for many patients, there are no studies on its use for patients with luteal phase defects. This study evaluated the efficacy of oral micronized progesterone for the treatment of luteal phase defects. STUDY DESIGN: Seven women with luteal phase defects previously corrected by vaginal suppositories were administered oral micronized progesterone (200 mg by mouth three times a day). Endometrial biopsies were performed to evaluate treatment efficacy. Questionnaires were used to assess side effects, including sedation. RESULTS: On oral micronized progesterone, all patients had in-phase endometrial biopsies. Despite complaints of drowsiness, the majority of patients preferred the oral formulation over the vaginal route of administration. CONCLUSION: We conclude that oral micronized progesterone is efficacious in the treatment of luteal phase defects.

Selective use of leuprolide acetate in women undergoing superovulation with intrauterine insemination results in significant improvement in pregnancy outcome.

OBJECTIVE: To examine the incidence of premature luteinization in individuals undergoing hMG with IUI therapy, the association between premature luteinization, cycle fecundity, and pregnancy outcome, and to determine if the selective use of leuprolide acetate (LA) in women demonstrating premature luteinization improves pregnancy outcome in subsequent hMG with IUI cycles. DESIGN AND SETTING: Retrospective analysis of superovulation cycles from January 1990 until December 1991 at the University of Connecticut Health Center. PATIENTS: All women with ovulatory function undergoing hMG superovulation with IUI. INTERVENTIONS: All patients were tested for evidence of premature luteinization. Those demonstrating premature luteinization were started on LA in the luteal phase in their subsequent hMG with IUI cycle. MAIN OUTCOME MEASURES: Peak serum E2, the number of mature preovulatory follicles, the number of ampules of hMG, days of hMG therapy, cycle fecundity, and spontaneous abortion rate. RESULTS: Thirty-three percent of all hMG with IUI patients showed evidence of premature luteinization, with premature luteinization occurring in 22.2% of conception cycles and 37.4% of nonconception cycles. For those women who demonstrated premature luteinization in their conception cycle, 90.0% of the pregnancies ended with either spontaneous abortion or were biochemical in nature compared with 44.3% in the cycles without evidence of premature luteinization. Cycle fecundity was 11.1% in patients demonstrating premature luteinization compared with 26.3% for patients without premature luteinization. All women demonstrating premature luteinization and not conceiving were placed on LA in the luteal phase and had a subsequent cycle fecundity of 18.9% with the percent pregnancy wastage being significantly less (33.3% versus 90.0%) when LA was used. CONCLUSIONS: Premature luteinization is a common occurrence during hMG therapy and is associated with decreased cycle fecundity and an increased incidence of spontaneous abortion and biochemical pregnancies. The selective use of LA in those individuals demonstrating premature luteinization results in a significant increase in the percent of women conceiving a viable pregnancy.

The value of increasing the dose of human menopausal gonadotropins in women who initially demonstrate a poor response.

OBJECTIVE: To evaluate the benefit of increasing the hMG dose in subsequent superovulation cycles for those individuals who demonstrate a poor response on up to three ampules of hMG daily. DESIGN AND SETTING: Retrospective analysis of all superovulation cycles at the University of Connecticut Health Center. PATIENTS: All women undergoing hMG therapy with IUI from January 1990 until December 1992. INTERVENTIONS: All patients were initially stimulated with up to three ampules of hMG daily. All patients who did not conceive on their first hMG cycle and demonstrated a poor response to hMG therapy were started on higher doses of hMG in an effort to obtain a good response. A maximum of eight ampules of hMG per day were used. MAIN OUTCOME MEASURES: Peak serum E2, the number of mature preovulatory follicles, and cycle fecundity were compared. RESULTS: The poor responders using up to three ampules daily had a peak E2 of 384 +/- 26 pg/mL (1,421 +/- 96 pmol/L), 1.4 +/- 0.1 mature follicles, and a cycle fecundity of 3.1% compared with an E2 of 900 +/- 83 pg/mL (3,330 +/- 307 pmol/L), 2.7 +/- 0.2 mature follicles, and a cycle fecundity of 4.3% when these poor responders had their dose increased to five or more ampules daily. Those individuals demonstrating a good response on less than or equal to three ampules of hMG daily had an average peak E2 of 1,159 +/- 41 pg/mL (4,288 +/- 151 pmol/L), 3.4 +/- 0.2 mature follicles, and a cycle fecundity of 16.5%. CONCLUSIONS: Despite significant improvement in peak E2 and the number of mature preovulatory follicles when the hMG dose was increased in poor responders, no significant increase in cycle fecundity was noted.

A randomized and longitudinal study of human menopausal gonadotropin with intrauterine insemination in the treatment of infertility.

OBJECTIVE: To study in a randomized and longitudinal manner the efficacy of human menopausal gonadotropin (hMG) superovulation combined with intrauterine insemination (IUI) versus IUI alone in the treatment of various causes of infertility in the presence of normal ovulation. METHODS: An initially randomized and subsequently longitudinal study of infertile couples was performed at a university-based clinical research center. One hundred nineteen couples with longstanding infertility (average duration 3.7 years) associated with male factor infertility, unexplained infertility, and/or endometriosis were enrolled. All patients were randomized in the initial cycle to treatment with either hMG/IUI or urine LH-timed IUI alone. They were then followed longitudinally as they alternated subsequent cycles between the two modalities. Outcome indices measured were cycle fecundity, pregnancy outcome, and cumulative pregnancy rates evaluated by life-table analysis. RESULTS: Human menopausal gonadotropin/IUI therapy was consistently more effective than IUI alone in the treatment of endometriosis, male factor infertility, and unexplained infertility, with cycle fecundities ranging from 7.1-19.0% versus 0-6.7%, respectively, during the first seven cycles. CONCLUSION: Human menopausal gonadotropin/IUI is a more effective therapy for enhancing fertility than is IUI alone for the treatment of endometriosis, male factor infertility, and unexplained infertility.

Conservative management of interstitial pregnancy.

Earlier detection of ectopic pregnancies allows the patient and physician the option of conservative management. Conservative surgical management of ampullary ectopic pregnancies has been well described. Traditional management of interstitial or cornual gestation has been by salpingectomy with or without cornual resection or by hysterectomy. In this paper we present a case report of alternative, less radical surgical management and review the literature on conservative surgical and medical management of interstitial pregnancies.

Evaluation of low-dose estrogen and progestin therapy in postmenopausal women. A double-blind, prospective study of sequential versus continuous therapy.

In this prospective, double-blind study, we evaluated the efficacy and safety of low-dose estrogen and progestin replacement therapy in 36 postmenopausal women who were administered oral medroxyprogesterone acetate (MPA) cyclically or continuously in combination with conjugated equine estrogen (CEE) 0.625 mg daily. In the sequential group, MPA (5.0 mg) was administered daily for 12 days of each 25-day treatment cycle. In the two continuous groups, MPA was administered without interruption at a daily dose of either 2.5 mg or 5.0 mg for 12 treatment cycles. Of the 36 women in the study, 29 women completed the one-year protocol. The clinical and metabolic responses were assessed before and every three cycles during the 12 cycles of treatment. Endometrial biopsies and lumbar bone density scans were performed before and during the last week of the 12th treatment cycle. Vasomotor and urogenital symptoms improved in all women. Cyclic menstrual bleeding occurred in all patients on sequential therapy, and proliferative endometrium was noted in two of these women. All patients in both continuous treatment groups experienced amenorrhea after the fifth cycle of therapy, and all endometrial biopsies were atrophic or inactive. From the 3rd through the 12th month of cycle, favorable lipid and lipoprotein changes occurred in all treatment groups. Lumbar bone mineral density improved significantly (P < .05) by an average of 6.41% in all patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Laser laparoscopy versus laparotomy in lysis of pelvic adhesions.

Severe adhesions were induced at laparotomy by laser ablation of the surface of one uterine horn and 1 cm2 of pelvic sidewall in 20 rabbits. Three weeks later the rabbits were selected at random for laparoscopy or laparotomy. Adhesions at the horn, sidewall and incidental sites were scored and lysed with laser at similar power densities. Three weeks later animals were killed and adhesions were blindly scored. We found a significant and similar reduction in severe adhesions at uterine horns after either laser laparoscopy or laser laparotomy, better lysis of sidewall and incidental adhesions by laser laparoscopy and formation of de novo adhesions at nonoperative sites after laparotomy but not after laparoscopy. We conclude that (1) de novo adhesions are common after laparotomy; (2) severe uterine horn adhesions can be reduced equally well by both laparoscopy and laparotomy but laparoscopy is superior to laparotomy with less severe peripheral adhesions; (3) outcome of adhesiolysis depends on several variables, including adhesion density and location and approach (laparotomy or laparoscopy), even when the tool (laser) is constant.

Sperm electron microscopy for the evaluation of in vitro fertilization failures.

When performing IVF, the clinician is frequently confronted with the failure of fertilization. When the standard parameters to evaluate the male factor are "within normal limits," the conclusion is often made that the lack of fertilization is most likely due to "poor egg quality." These two cases demonstrate the fallacy of this approach and support a more rigorous evaluation of the male factor. Ultrastructural analysis of sperm is underutilized and, as demonstrated by these two cases, can play an essential role in this evaluation process.

The relationship between alterations in spermatozoal deoxyribonucleic acid, heparin binding sites, and semen quality.

OBJECTIVE: To assess the relationship between spermatozoal deoxyribonucleic acid (DNA) and fertilizing potential. DESIGN: Semen samples were examined from nine fertile donors and six donors without a confirmed pregnancy. All samples were in the normal range for count, morphology, and motility. Spermatozoa from these specimens were stained with acridine orange or Feulgen's reagent. The presence of heparin binding sites was determined by counting the number of spermatozoa that bound to heparin-coated agarose beads. RESULTS: Acridine orange staining demonstrated that in the fertile group 42% +/- 2% of the spermatozoa fluoresced green indicating that the DNA was intact, whereas only 25% +/- 3% of the spermatozoa fluoresced green in the nonfertile group (P less than 0.05). Feulgen's staining revealed that more spermatozoa from infertile donors showed a heterogeneous DNA distribution (P less than 0.05). The DNA content of spermatozoa with heterogeneous distribution of DNA was reduced by 10% compared with those with homogeneous DNA (P less than 0.05). Normal spermatozoa as well as those with DNA anomalies possessed heparin binding sites. CONCLUSIONS: These data demonstrated that in donor specimens with normal counts, morphology, and motility, a higher percentage of spermatozoa possess less and/or denatured DNA in the infertile group compared with the fertile donors. In contrast, the surface membranes of spermatozoa with altered DNA have heparin binding sites as do spermatozoa with intact DNA.

Effect of pulse amplitude of luteinizing hormone, duration and rate of change on progesterone secretion from rat corpora lutea.

Corpora lutea (CL) were obtained from immature rats primed with pregnant mares' serum gonadotrophin followed by human chorionic gonadotrophin (hCG). Two days after hCG, CL were isolated, placed in perifusion culture and exposed to control medium or specific pulses of luteinizing hormone (LH). In Expt 1, a frequency of 1 pulse LH/h (amplitude 500 pg/ml, duration 40 min, 30 ng/min) increased progesterone secretion compared with control values (P less than 0.05). In Expt 2, LH rate was held constant and the amplitude and duration of a single LH pulse varied; 250 and 500 ng LH/ml initially stimulated progesterone secretion equivalently, but increasing the duration of the LH pulse prolonged high progesterone secretion. These observations suggest that at less than or equal to 500 ng LH/ml, once a stimulatory amplitude is obtained, higher amplitudes do not further increase progesterone secretion, while increasing pulse duration further enhances progesterone secretion. In Expt 3, the LH pulse amplitude was 250 ng/ml and the rate set at 0, 5 or 30 ng LH/min; only 30 ng LH/min resulted in sustained stimulation of progesterone (P less than 0.05). Taken together, these data demonstrate that the characteristics which determine whether an LH pulse will be stimulatory include not only amplitude and duration but also the rate at which an amplitude is obtained.

Effect of rate of change of luteinizing hormone concentration on in-vitro progesterone secretion within rat corpora lutea during differentiation.

Immature rats were injected with pregnant mares' serum gonadotrophin followed by human chorionic gonadotrophin (hCG). Ovaries were removed 0, 2, 5 or 8 days after hCG and either prepared for morphometric analysis or perifused with 0, 5 or 30 ng luteinizing hormone (LH)/min. In a second study, ovaries were removed on Day 2 or 8 and perifused with 0.1 mg 8-br-cyclic adenosine 5'-phosphate/ml (8-br-cAMP). On Day 0, the granulosa cells of the preovulatory follicles were small (53 +/- 0.5 microns2) with a cytoplasmic to nuclear (Cy:Nu) ratio less than or equal to 1.5. By Day 2, corpora lutea (CL) were present and composed of 95% small luteal cells (diameter less than 125 microns2, Cy:Nu greater than or equal to 3.0) and 5% large luteal cells (diameter greater than 125 microns2, Cy:Nu ratio greater than or equal to 3.0). The percentage of large luteal cells increased to 36 +/- 7% by Day 5, suggesting that they are derived from a select population of small luteal cells. Basal progesterone secretion increased from 38 +/- 5 on Day 0 to 1010 +/- 48 pg/mg/ml on Day 8. The rate of 5 ng LH/min stimulated progesterone secretion on Days 0, 2 and 8; 30 ng LH/min stimulated progesterone secretion on Days 0, 2 and 8, but not on Day 5; 8-br-cAMP stimulated progesterone secretion on both Days 2 and 8. These data demonstrate that once granulosa cells are induced to luteinize they lose their capacity to secrete progesterone in response to 5 ng LH/min and do not regain their responsiveness to LH rate until they completely differentiate. The loss of this LH responsiveness appears to be due to an inability to stimulate sufficient intracellular cAMP concentrations, since cAMP stimulates progesterone secretion on both Days 2 and 8.

A comparative analysis of the cycle fecundity rates associated with combined human menopausal gonadotropin (hMG) and intrauterine insemination (IUI) versus either hMG or IUI alone.

Human menopausal gonadotropin (hMG) superovulation combined with washed intrauterine insemination (IUI) has been advocated for the treatment of various forms of infertility when more traditional therapy has failed. To assess the relative efficacy of combined treatment with hMG and IUI compared with either hMG or IUI alone, pregnancy outcomes of the three treatment groups were compared in couples having infertility because of male factor, cervical factor, endometriosis, or unexplained. A total of 751 cycles were analyzed from 322 couples. The mean cycle fecundity rate associated with hMG/IUI therapy was significantly higher than either hMG or IUI therapy alone for all patients (hMG/IUI = 19.6%, hMG = 6.3%, IUI = 3.4%). The improvement in cycle fecundity rates with hMG/IUI therapy was also observed when the couples were separated by infertility diagnostic groups: male factor (hMG/IUI = 15.3%, hMG = 4.4%, IUI = 3.0%), cervical factor (hMG/IUI = 26.3%, hMG = 7.9%, IUI = 5.1%), endometriosis (hMG/IUI = 12.85%, hMG = 6.6%), and unexplained infertility (hMG/IUI = 32.6%, hMG = 5.5%, IUI = 0%). Moreover, in patients who had failed to conceive with hMG or IUI alone, the cycle fecundity rate when they were switched to hMG/IUI therapy equaled that of patients who received combined therapy from the onset. We conclude that cycle fecundity rates and cumulative pregnancy rates are significantly greater using a combination of hMG and IUI compared with either modality alone in the treatment of male factor, cervical factor, endometriosis, or unexplained infertility. Indeed, in couples with nontubal related infertility, cycle fecundity rates with hMG/IUI approach the rates seen with in vitro fertilization and gamete intrafallopian tube transfer.

Identification of follicles with fertilizable oocytes by sequential ultrasound measurements during follicular development.

Patients undergoing ovulation induction for in vitro fertilization and embryo transfer (IVF-ET) were monitored daily with serum estradiol-17 beta (E2) and ultrasound. The location of each individual follicle was established by taking ultrasound images through serial sections of the ovary. The diameter of each follicle and the volume of its follicular wall (FW) were determined from ultrasound images using a computer-controlled image analyzer. A total of 44 follicles from nine patients was studied, with an overall fertilization rate of 46% In all patients, serum E2 levels increased prior to human chorionic gonadotropin (hCG). Whereas changes in either the average diameter or the volume of the entire follicle did not identify follicles with fertilizable oocytes, FW volume measurements were predictive. Prior to hCG, FW volume increased 24 +/- 8%/day in follicles with fertilizable oocytes but decreased 3 +/- 6%/day in follicles with nonfertilizable oocytes (P less than 0.05). Three major patterns of follicular development were observed for follicles with nonfertilizable oocytes: slow growing (less than 20% increase in FW volume), nongrowing (no change in the FW volume), and "degenerating" (a decrease in the FW volume), suggesting that these follicles are "postmature." These data demonstrate that FW volume measurements made from sequential ultrasound images provide an accurate method to identify those follicles that contain fertilizable oocytes.

A comparative study of postoperative adhesions following laser surgery by laparoscopy versus laparotomy in the rabbit model.

In this study, we tested the null hypothesis that intraperitoneal adhesion formation and reduction after laser surgery are the same whether the surgery is performed by laparoscopy or laparotomy. Twenty rabbits were randomly assigned to either laparoscopy or laparotomy and subjected to standardized laser incisions over one uterine horn and over the peritoneal surface of either lower quadrant. Three weeks later, five animals from each group underwent laparoscopy and the other five received laparotomy to score the extent of postoperative adhesions formed and to carry out laser adhesiolysis. The same power density was delivered to tissues in both procedures. Three weeks after the second operative intervention, the animals were killed and the intraperitoneal adhesions blindly scored (scale of 0-3). After the initial procedure, adhesions were absent in the laparoscopy group, but in the laparotomy group, adhesions were frequently present not only at the operative sites of the peritoneal surfaces and uterine horn, but also on the bowel, bladder, and opposite uterine horn where no apparent injury had been inflicted (P less than .005). Three weeks after adhesiolysis, a significant reduction was observed in the mean adhesion scores in the laparoscopy group, but not in the laparotomy group (P = .001). These results lead to the rejection of the null hypothesis and confirm the clinical observation that besides reducing operative trauma, discomfort, and cost, laparoscopic laser surgery is very effective in reducing intraperitoneal adhesions and causes significantly less postoperative adhesion formation than does laparotomy.

Control of the steroidogenic machinery of the human trophoblast by cyclic AMP.

Human cytotrophoblasts express adenylate cyclase activity and possess membrane-bound regulatory proteins that bind guanine nucleotides (G proteins). Stimulation of the cyclase by forskolin or addition of 8-bromo-cAMP augments progesterone secretion by cultured cytotrophoblasts at least in part, by promoting accumulation of components of the cholesterol side-chain cleavage system. This is the consequence of increased synthesis of the proteins participating in steroidogenesis as a result of the 8-bromo-cAMP-provoked increase in their respective mRNAs. We propose that progesterone synthesis by cytotrophoblasts is up-regulated by cyclic AMP, which acts to increase expression of genes encoding the steroidogenic machinery. Paracrine or autocrine factors may initiate this cascade by stimulating the cytotrophoblast adenylate cyclase.

Adenylate cyclase in human cytotrophoblasts: characterization and its role in modulating human chorionic gonadotropin secretion.

Our previous work demonstrated that 8-bromo-cAMP promotes the secretion of both hCG and progesterone by cultured cytotrophoblasts. This study was conducted to characterize the adenylate cyclase of cytotrophoblasts and to examine the effects of agents that stimulate adenylate cyclase on hCG secretion. Adenylate cyclase activity was detected in purified cytotrophoblasts, as were membrane-bound stimulatory and inhibitory guanine nucleotide regulatory proteins, Gs and Gi. Adenylate cyclase was stimulated by MnCl2 and MgCl2, and the effects of MgCl2 were amplified by the GTP analog guanylylimidodiphosphate. Cholera toxin stimulated both cAMP and hCG production by cultured cytotrophoblasts, confirming the coupling of Gs to the adenylate cyclase. Forskolin also stimulated adenylate cyclase, cAMP synthesis, and hCG secretion. Pertussis toxin did not affect hCG secretion in either the absence or presence of forskolin. 8-Bromo-cAMP stimulated cytotrophoblast protein kinase activity, resulting in the increased phosphorylation of a protein with a mol wt of about 70,000, and produced a marked stimulation of hCG secretion. Our findings suggest that the level of expression of adenylate cyclase activity is one determinant of the endocrine function of the differentiating trophoblast.