Prognostic value of histological type in stage IV ovarian carcinoma: a retrospective analysis of 223 patients.

BACKGROUND: Patients with FIGO stage IV epithelial ovarian carcinoma have a poor but non-uniform prognosis. This study aimed to compare the survival of patients with serous or endometrioid tumours (S/E) and clear cell or mucinous tumours (non-S/E). METHODS: Data for 223 patients who underwent surgery between 1987 and 2010 and were diagnosed by centralized pathology review and were retrospectively analysed. The patients included 169 with S/E tumours and 54 with non-S/E tumours. RESULTS: The median overall survivals (OSs) of the S/E and non-S/E groups were 3.1 and 0.9 years, respectively (P<0.001). Six patients (2.7%), all with non-S/E tumours, died within 6 weeks after the initial surgery. Multivariate OS analysis revealed that performance status, residual tumor, metastatic sites, no debulking surgery, and non-S/E tumours were independent poor prognostic factors. For patients with non-S/E tumours, prognosis was more favourable for single-organ metastasis, except for liver or distant lymph nodes, no residual tumor, and resection of metastasis (median OS: 4.1, 4.6, and 2.6 years, respectively). CONCLUSIONS: In stage IV ovarian carcinoma, non-S/E tumours are associated with a significantly poorer prognosis and higher rates of early mortality compared to S/E tumours. Therefore, careful management and development of new strategies are required.

Identification of a naturally processed HLA-Cw7-binding peptide that cross-reacts with HLA-A24-restricted ovarian cancer-specific CTLs.

Here, we describe an human leukocyte antigen (HLA)-A*24:02-restricted cytotoxic T-lymphocyte (CTL) clone, 1G3, established from naïve CD8(+) T-lymphocytes obtained from a healthy donor stimulated with HLA-modified TOV21G, an ovarian cancer cell line. The 1G3 clone responds not only to ovarian cancer cells in the context of HLA-A*24:02 but also to allogeneic HLA-Cw*07:02 molecules through cross-reactive T-cell receptor recognition. Expression screening using a complementary DNA library constructed from TOV21G messenger RNA revealed that this alloreactivity was mediated through the nine-mer peptide VRTPYTMSY, derived from RNA-binding motif protein 4. To our knowledge, this study presents the first example of the allorecognition of an HLA-Cw molecule by HLA-A-restricted T-cells, thereby revealing a naturally processed epitope peptide. These findings provide the structural bases for the allorecognition of human T-cells. In addition, this study suggests that unexpected alloresponses occur in certain HLA combinations, and further study is needed to understand the mechanisms of alloreactivity for better prediction of alloresponses in clinical settings.

Uterine sutures at prior caesarean section and placenta accreta in subsequent pregnancy: a case-control study.

OBJECTIVE: To clarify the effects of uterine myometrial suture techniques at prior caesarean section on the incidence of pathologically diagnosed placenta accreta in placenta praevia with prior caesarean section (PPPC). DESIGN: Case-control study. SETTING: Eleven tertiary referral hospitals in central Japan. POPULATION: A total of 98 cases of placenta praevia, a history of one or more prior caesarean sections, and a history of uterine transverse incision and usage of only absorbable thread for myometrial sutures at the prior caesarean section. Exclusions were a history of myomectomy or Strassmann's operation. METHODS: Cases were grouped into a pathologically diagnosed placenta accreta group (38 cases) and a no accreta group (60 cases). Clinical characteristics including uterine suture methods at prior caesarean section were compared (single-layer versus double-layer closure; continuous versus interrupted sutures in the inner myometrial layer). MAIN OUTCOME MEASURE: The incidence of placenta accreta. RESULTS: No difference was found comparing single-layer with double-layer closure in the incidence of placenta accreta (37.1 versus 39.7%, P = 0.805); however, a significant difference was found comparing continuous with interrupted sutures (58.1 versus 29.9%, P = 0.008). Multivariable logistic regression analysis with stepwise selection for the eight factors meeting the criterion of P < 0.10 in univariate analysis was used, and four independent factors were selected, as follows: gravidity ≥ 3 (adjusted odds ratio, aOR, 3.4, 95% confidence interval, 95% CI, 0.99-11.6, P = 0.050); total praevia (versus non-total, aOR 18.4, 95% CI 3.2-107.0, P = 0.001); anterior/centre placenta (versus posterior, aOR 16.4, 95% CI 3.7-72.2, P < 0.001); and continuous sutures (versus interrupted, aOR 6.0, 95% CI 1.4-25.2, P = 0.015). CONCLUSIONS: In this limited study, a history of continuous sutures on the inner side of the uterine wall showed potential to influence the development of placenta accreta in PPPC patients.

High expression of N-acetylglucosaminyltransferase IVa promotes invasion of choriocarcinoma.

BACKGROUND: Gestational trophoblastic diseases (GTDs) are related to trophoblasts, and human chorionic gonadotropin (hCG) is secreted by GTDs as well as normal placentas. However, the asparagine-linked sugar chains on hCG contain abnormal biantennary structures in invasive mole and choriocarcinoma, but not normal pregnancy or hydatidiform mole. N-acetylglucosaminyltransferase-IV (GnT-IV) catalyses ß1,4-N-acetylglucosamine branching on asparagine-linked oligosaccharides, which are consistent with the abnormal sugar chain structures on hCG. METHODS: We investigated GnT-IVa expression in GTDs and placentas by immunohistochemistry, western blot, and RT-PCR. We assessed the effects of GnT-IVa knockdown in choriocarcinoma cells in vitro and in vivo. RESULTS: The GnT-IVa was highly expressed in trophoblasts of invasive mole and choriocarcinoma, and moderately in extravillous trophoblasts during the first trimester, but not in hydatidiform mole or other normal trophoblasts. The GnT-IVa knockdown in choriocarcinoma cells significantly reduced migration and invasive capacities, and suppressed cellular adhesion to extracellular matrix proteins. The extent of ß1,4-N-acetylglucosamine branching on ß1 integrin was greatly reduced by GnT-IVa knockdown, although the expression of ß1 integrin was not changed. In vivo studies further demonstrated that GnT-IVa knockdown suppressed tumour engraftment and growth. CONCLUSION: These findings suggest that GnT-IVa is involved in regulating invasion of choriocarcinoma through modifications of the oligosaccharide chains of ß1 integrin.

Psychological stress during in vitro fertilization and embryo transfer is influenced by the patients' background and gender.

Purpose: This study evaluated the changes in psychological stress during in vitro fertilization and embryo transfer (IVF-ET) and the relationship of such stress to the patients' background and gender. Methods: Sixty couples undergoing IVF-ET were administered the State-Trait Anxiety Inventory-JYZ (STAI) test at six different points during IVF-ET procedures. Anxiety scores at each time point were recorded and analyzed according to gender, fertility status, and duration of treatment. Results: The median state anxiety score for women increased following induction until oocyte collection, after which it temporarily declined and then increased again until the pregnancy test. No such changes were noted in men. Scores for women who had undergone a shorter period of IVF treatments were higher while state and trait anxiety in men increased with a prolonged treatment period. Unsuccessful treatment increased the state and trait anxiety of women. Conclusions: Psychological stress changed periodically depending on the duration of the patients' treatment and fertility status also influenced anxiety levels. These findings will prove helpful in guiding psychological therapy and counseling for couples attempting to conceive by in vitro fertilization.

Long-term survival of young women receiving fertility-sparing surgery for ovarian cancer in comparison with those undergoing radical surgery.

OBJECTIVES: To compare the clinical outcome of patients with stage I epithelial ovarian cancer (EOC) who received with fertility-sparing surgery (FSS) with those who underwent radical surgery (RS). METHODS: After a central pathological review and search of the medical records from multiple institutions, a total of 572 patients were retrospectively evaluated. All patients were divided into three groups: group A {FSS (n=74); age, ≤ 40}; groups B and C [RS; age, 40 ≥{(B), n=52}; 40<{(C), n=446}]. RESULTS: Five-year overall survival (OS) and disease-free survival (DFS) rates of patients in the groups were as follows: group A, 90.8% (OS)/87.9% (DFS); group B, 88.3% (OS)/84.4% (DFS); group C, 90.6% (OS)/85.3% (DFS), respectively (OS, P=0.802; DFS, P=0.765). Additionally, there was no significant difference in OS and DFS among the three groups stratified to stage IA or IC (OS (IA), P=0.387; DFS (IA), P=0.314; OS (IC), P=0.993; DFS (IC), P=0.990, respectively). Furthermore, patients with a grade 1-2 or 3 tumours in the FSS group did not have a poorer prognosis than those in the RS group. CONCLUSIONS: Stage I EOC patients treated with FSS showed an acceptable prognosis compared with those who underwent RS.

Twist expression in patients with cervical cancer is associated with poor disease outcome.

BACKGROUND: Twist, a basic helix--loop-helix transcription factor, has been reported to be associated with the development and progression of human cancer. We examined the distribution and expression of Twist in cervical cancer to examine its clinical significance. PATIENTS AND METHODS: We examined the distribution and expression of Twist in 101 cervical cancer specimens and determined the association between their expression and the clinico-pathological features observed, including patient outcome. RESULTS: Of the 101 specimens, 55 cases were negative for Twist immuno-expression, whereas 46 were positive. When categorized into negative versus positive expression, Twist was not associated with any of the clinico-pathological parameters examined. Positive Twist expression significantly predicted poorer overall survival (OS) and progression-free survival (PFS) when compared with negative expression (P < 0.01). In the multivariate analyses, positive Twist expression was an independent prognostic factor for OS (P < 0.05). CONCLUSIONS: Our data imply that positive Twist expression seems to be a useful marker in patients with cervical cancer likely to have an unfavorable clinical outcome.

Is there any association between retroperitoneal lymphadenectomy and survival benefit in ovarian clear cell carcinoma patients?

BACKGROUND: To estimate the survival impact of systemic retroperitoneal lymphadenectomy in patients diagnosed with International Federation of Gynecology and Obstetrics pTI-IIb clear cell carcinoma of the ovary (CCC). PATIENTS AND METHODS: Demographic and clinicopathologic data were obtained from the Tokai Ovarian Tumor Study Group between 1986 and 2006. Survival curves were calculated using the Kaplan-Meier method. Differences in survival rates were analyzed using the log-rank test. RESULTS: A total of 205 patients had clinical pTI-IIb CCC (median age: 52 years, range: 30-75). One hundred and four (50.7%) patients underwent systemic retroperitoneal lymphadenectomy. Lymphadenectomy was not associated with improved disease-free and overall survival in all patients (P = 0.353 and P = 0.645, respectively). Moreover, lymphadenectomy did not improve the overall survival in those with pTIc CCC (P = 0.433). Similarly, on univariate analysis, age, volume of ascites, preoperative CA 125 values, and regimen of chemotherapy were not significant factors. In addition, there was no significant difference in the ratio of positive lymph node metastases regardless of the completion of lymphadenectomy (P = 0.955). CONCLUSION: Our data suggest that patients with pTI-IIb CCC who underwent lymphadenectomy did not show a significant improvement in survival. There was no significant difference in the overall and disease-free survival rates in pTI-IIb CCC patients regardless of the completion of surgical staging lymphadenectomy.

Characterization of a thyroid-specific enhancer located 5.5 kilobase pairs upstream of the human thyroid peroxidase gene.

A 6.3-kbp segment of DNA, upstream of the human thyroid peroxidase gene, and various deletions thereof were linked to a promoterless bacterial chloramphenicol acetyltransferase reporter gene. These constructs were analyzed by transfection and expression in rat FRTL-5 thyroid cells and in human hepatoma HepG2 cells to localize sequences that are important for thyroid cell-specific expression of the thyroid peroxidase gene. A thyroid-specific enhancer element, capable of activating enhancerless simian virus 40 promoter expression in FRTL-5 cells, was localized to a 230-bp region approximately 5.5 kbp upstream of the human thyroid peroxidase gene transcription start site. DNase I footprinting, using nuclear extracts prepared from FRTL-5 cells, revealed three regions within the 230-bp fragment; none of these regions were protected by nuclear extracts from HepG2 cells. Gel mobility shift assays, using double-stranded oligonucleotides corresponding to the three protected regions, further confirmed the existence of factors in FRTL-5 cells, but not HepG2 cells, able to specifically bind to the enhancer sequences. These results suggest the presence of three cis-acting DNA elements in the human thyroid peroxidase gene enhancer that interact with thyroid-specific trans-acting factors.

Angiotensin II augmented migration and invasion of choriocarcinoma cells involves PI3K activation through the AT1 receptor.

While angiotensin II (Ang II) has been shown to inhibit migration of extravillous trophoblasts via plasminogen activator inhibitor-1 (PAI-1) activation, it has remained unclear whether it stimulates or inhibits malignant behavior of choriocarcinoma cells. Since we previously found an involvement of the renin-angiotensin system (RAS) in the proliferative potential in choriocarcinoma cells (BeWo), mediated via the Ang II type 1 receptor (AT1R), in the present study we investigated the effects of Ang II on choriocarcinoma cell migration/invasion in vitro using Transwell cell culture chambers. Ang II (10(-8)M) promoted migration and invasion by a choriocarcinoma cell line and augmented random cell mobility on checkerboard analysis. Immunoblotting showed Ang II to activate the phosphorylation of FAK and Akt in BeWo cells. Furthermore Ang II effects on cell migration were abolished by a selective AT1R antagonist and a phosphatidylinositol 3-kinase (PI3K) inhibitor. The present results suggest that Ang II-induced migration and invasion of choriocarcinoma cells probably involves PI3K following binding to the AT1R.

Fibronectin secretion from human peritoneal tissue induces Mr 92,000 type IV collagenase expression and invasion in ovarian cancer cell lines.

Our previous study showed that human peritoneal conditioned medium (CM) increased the matrix metalloproteinase-9 (MMP-9) secretion and invasiveness of ovarian cancer cells (NOM1). In an effort to identify this MMP-9-stimulating factor, we examined the effects of extracellular matrix components, such as type IV collagen, laminin, and fibronectin, on ovarian cancer cells. We found that fibronectin increased the MMP-9 activity of NOM1 cell CM in a concentration-dependent manner and that the peritoneal CM contained high level of fibronectin. An increase of MMP-9 activity in NOM1 cell CM by the peritoneal CM was almost completely blocked by 20 microg/ml of anti-integrin alpha5/FnR antibody and RGD polypeptides. Furthermore, after immunoprecipitation by antifibronectin antibody supernatant of the peritoneal CM did not increase MMP-9 activity in NOM1 cells. Fibronectin and the peritoneal CM also increased MMP-9 activity and expression in NOM1 cell lysate, and these effects were blocked by anti-integrin alpha5/FnR antibody. Invasiveness of NOM1 cells was enhanced by fibronectin and the peritoneal CM in a concentration-dependent manner, and anti-integrin alpha5/FnR antibody blocked these effects. These results suggested that fibronectin secreted from peritoneum increased MMP-9 activity and expression, and, in turn, invasiveness of ovarian cancer cells.

Both focal adhesion kinase and c-Ras are required for the enhanced matrix metalloproteinase 9 secretion by fibronectin in ovarian cancer cells.

Cell adhesion to the extracellular matrix appears to trigger a cascade of intracellular signalings. We have shown previously that treatment of ovarian cancer cells with peritoneal conditioned medium or purified fibronectin (FN) activated matrix metalloproteinase 9 secretion and, thereby, cancer cell invasion. By use of antisense oligonucleotides to focal adhesion kinase (FAK) and a dominant-negative mutant of ras (S17Nras), we found that both FAK and c-Ras were required for the activation of matrix metalloproteinase 9 secretion by FN. In addition, both antisense oligonucleotides to FAK and S17Nras inhibited mitogen-activated protein kinase activation by FN treatment, suggesting the involvement of mitogen-activated protein kinase in the FN-dependent signaling.

The Ras-mitogen-activated protein kinase pathway is critical for the activation of matrix metalloproteinase secretion and the invasiveness in v-crk-transformed 3Y1.

To search for the intracellular signaling pathway critical for the secretion of matrix metalloproteinases (MMP), we studied the effects of dominant negative Ras (S17N Ras) and dominant negative MEK1 (MEK1AA) expression in v-crk-transformed 3Y1. Expression of either S17N Ras or MEK1AA dramatically suppressed the augmented secretion of MMP-2 and MMP-9 in v-crk-transfected 3Y1. Similarly, a Ras farnesyltransferase inhibitor, manumycin A, and a MEK1 inhibitor, U0126, suppressed MMP secretion in a dose-dependent manner, whereas a PI3 kinase inhibitor, wortmannin, could not. In addition, the suppression of MMP secretion by S17N Ras showed good correlation with the inhibition of in vitro invasiveness of the cells. In contrast, expression of dominant negative C3G did not suppress MMP secretion, although it substantially blocked the c-Jun N-terminal kinase activation. Taken together, the Ras-MEK1 pathway, but not the C3G-JNK pathway, seems to play a key role in the activation of MMP secretion and, hence, the invasiveness of v-crk-transformed cells.

A newly synthesized bifunctional inhibitor, W-77, enhances adriamycin activity against human ovarian carcinoma cells.

A newly synthesized calmodulin antagonist, (S)-P-(2-aminoethyloxy)-N-[2-(4-benzyloxy-carbonylpiperazinyl++ +)-1-(P-methoxybenzyl)ethyl]-N-methylbenzenesulfonamide dihydrochloride (W-77), acts as a calcium-independent uncompetitive antagonist which binds to glutathione-S-transferase (GST). We purified GST from human placenta using drug affinity chromatography on a column of W-77 coupled with Sepharose 6B and demonstrated that W-77 bound to GST. A spectrophotometric assay also showed that W-77 inhibited GST activity. We prepared Adriamycin-resistant and -sensitive cells from human ovarian serous cystadenocarcinomas. Immunoblot analysis revealed that GST expression was increased in the Adriamycin-resistant cells. We also purified GST from Adriamycin-resistant cells and found that W-77 bound to the GST obtained from these ovarian carcinoma cells. Adriamycin resistance was partially overcome by the addition of W-77 (10 microM) to the cultured cells. In addition, we investigated the effect of W-77 on P-glycoprotein. Northern blot analysis revealed MDR1 gene expression in Adriamycin-resistant cells. Although W-77 was less potent in increasing the intracellular Adriamycin content than verapamil, it was more effective in overcoming Adriamycin resistance. These results suggest that W-77 enhances the antitumor activity of Adriamycin by inhibiting both GST and P-glycoprotein.

Ras pathway is required for the activation of MMP-2 secretion and for the invasion of src-transformed 3Y1.

To search for the signaling pathway critical for tumor invasion, we examined the effects of dominant negative ras (S17N ras) expression on the activation of matrix metalloproteinase-2 (MMP-2) in src-transformed 3Y1, SR3Y1, under the control of conditionally inducible promoter. In SR3Y1 clones transfected with S17N ras, augmented secretion and proteolytic activation of MMP-2 were dramatically suppressed by S17N Ras expression, while tyrosine phosphorylation of cellular proteins was not suppressed. We found that invasiveness of SR3Y1 cells assayed by the modified Boyden Chamber method was strongly suppressed by S17N Ras expression. In contrast, cell morphology reverted partially and glucose uptake remained unchanged by S17N Ras expression. In addition, treatment of SR3Y1 with manumycin A, a potent inhibitor of Ras farnesyltransferase, strongly suppressed both augmented secretion and proteolytic activation of MMP-2. Contrary, treatment of SR3Y1 with wortmannin or TPA showed no clear effect on MMP-2 activation. Thus, these results strongly suggest that Ras-signaling, but neither P13 kinase- nor protein kinase C-signalings, plays a critical role in activation of MMP-2 and, subsequently, in the invasiveness of src-transformed cells.

Effects of 17 beta-estradiol and progesterone on growth-factor-induced proliferation and migration in human female aortic smooth muscle cells in vitro.

OBJECTIVE: The significantly low prevalence of atherosclerotic cardiovascular disease in premenopausal women has been noted, and postmenopausal hormone replacement therapy (HRT) is associated with protection from this disease. The aim of this study was to investigate the effects of estrogen and progestin on growth-factor-induced vascular smooth muscle cell (VSMC) proliferation and migration in vitro. METHODS: Two cell lines of human female aortic smooth muscle cells (AOSMCs) were used for the study. DNA synthesis was evaluated by [3H]thymidine incorporation into cells. Migration assay was performed using modified Boyden chambers. RESULTS: The presence of estrogen receptors was determined by Western and Northern blot analyses. [3H]Thymidine incorporation into AOSMCs was induced by 10 ng/ml EGF alone, the combination of 10 ng/ml EGF with 2 ng/ml b-FGF-induced and 1 nM PDGF-BB alone. Migration of AOSMCs was induced by PDGF-BB. Since 17 beta-estradiol (E2, 10(-9) M approximately 10(-6) M) inhibited the [3H]thymidine incorporation into AOSMCs stimulated by above mitogens and the 1 nM PDGF-BB-induced AOSMC migration in a dose-dependent manner, estrone (E1), estriol (E3) and progesterone (P) had no significant effects. The combination of P (10(-9) M approximately 10(-6) M) did not show any effect on these inhibitory effects of 10(-7) M E2. Preincubation of AOSMCs with the anti-estrogenic agent, tamoxifen (10(-6) M), significantly antagonized these inhibitory effects of 10(-7) M E2. CONCLUSIONS: These findings suggest that the inhibitory effect of E2 on VSMC proliferation and migration might be one of the factors involved in the decreased incidence of atherosclerotic cardiovascular disease in premenopausal women and postmenopausal HRT, and P might not affect these estrogenic responses.

Maternal molecular hydrogen treatment attenuates lipopolysaccharide-induced rat fetal lung injury.

Maternal inflammation is associated with spontaneous preterm birth and respiratory impairment among premature infants. Recently, molecular hydrogen (H2) has been reported to have a suppressive effect on oxidative stress and inflammation. The aim of this study was to evaluate the effects of H2 on fetal lung injury caused by maternal inflammation. Cell viability and the production of interleukin-6 (IL-6) and reactive oxygen species (ROS) were examined by treatment with lipopolysaccharide (LPS) contained in ordinal or H2-rich medium (HM) using a human lung epithelial cell line, A549. Pregnant Sprague Dawley rats were divided into three groups: Control, LPS, and HW + LPS groups. Rats were injected with phosphate-buffered saline (Control) or LPS intraperitoneally (LPS) on gestational day 19 and provided H2 water (HW) ad libitum for 24 h before LPS injection (HW + LPS). Fetal lung samples were collected on day 20, and the levels of apoptosis, oxidative damage, IL-6, and vascular endothelial growth factor (VEGF) were evaluated using immunohistochemistry. The number of apoptotic cells, and levels of ROS and IL-6 were significantly increased by LPS treatment, and repressed following cultured with HM in A549 cells. In the rat models, the population positive for cleaved caspase-3, 8-hydroxy-2'-deoxyguanosine, IL-6, and VEGF was significantly increased in the LPS group compared with that observed in the Control group and significantly decreased in the HW + LPS group. In this study, LPS administration induced apoptosis and oxidative damage in fetal lung cells that was ameliorated by maternal H2 intake. Antenatal H2 administration may decrease the pulmonary mobility associated with inflammation in premature infants.

Effects of the mutations (Trp8 --> Arg and Ile15 --> Thr) in human luteinizing hormone (LH) beta-subunit on LH bioactivity in vitro and in vivo.

The mutations (Trp8 --> Arg and Ile15 --> Thr) in the human LHbeta -subunit caused by nucleotide point mutations in the LHbeta gene were reported in women with immunologically anomalous LH and menstrual disorders. To estimate the effects of the mutations on LH bioactivity in vitro and in vivo, we constructed a LHbeta gene containing this nucleotide mutation in each site or in both sites by site- directed mutagenesis and analyzed the bioactivities of the mutant LH expressed in Chinese hamster ovary cells. Although no alterations were noted in the receptor-binding activity of LH due to the mutations, the LHs containing the mutations at Trp8 --> Arg and at both sites in the beta-subunit showed a higher biopotency of progesterone production in vitro. The clearance rate from the circulation was faster in vivo in all mutant LHs, which were induced primarily by the mutation at Trp8 --> Arg. However, the mutations did not affect the ability of LH to induce ovulation in vivo. These results indicate that LH consisting of the mutant beta-subunit exhibits hyperbioactivity on steroidogenesis and has a short turnover rate. This may affect the endocrine pathway among women with the mutant LH and lead to menstrual disorders.

Ontogenesis of pituitary prolactin in the human fetus.

To study the ontogenesis of PRL synthesis and secretion in the human fetus, PRL mRNA was measured in 12 pituitaries from fetuses of 16-27 weeks of gestation by hybridization of cytosol RNA with 125I-labeled single stranded complementary DNA (cDNA). Pituitary PRL content and serum PRL concentration were assessed by RIA. Pituitary weight increased with fetal age, ranging from 12 mg at 16 weeks of gestation to 41 mg at 27 weeks. The increased weight was due to an increase in cell number. PRL mRNA content did not change during weeks 16-20 of gestation. However, it increased rapidly after 21 weeks, reaching 11.5 times the 16-20 week value at 27 weeks. Pituitary PRL content was constant at a low level until 21 weeks, but thereafter it increased markedly. The increase was greater than that in PRL mRNA, and therefore, the PRL to PRL mRNA ratio was 10-fold greater at 27 weeks of gestation. Serum PRL concentrations also gradually increased after 21 weeks of gestation. These results indicate that marked increases in fetal pituitary PRL synthesis and release occur after 21 weeks of gestation.