Mareo Yamoto

Localization of gonadotropin binding sites in human ovarian neoplasms

The binding of human luteinizing hormone and human follicle-stimulating hormone to ovarian tumor biopsy specimens from 29 patients was analyzed. The binding sites for human luteinizing hormone were demonstrated in one tumor of epithelial origin (mucinous cystadenoma) and in one of sex cord-stromal origin (theca cell tumor). The binding sites for human follicle-stimulating hormone were found in three tumors of epithelial origin (serous cystadenoma and mucinous cystadenoma) and in two of sex cord-stromal origin (theca cell tumor and theca-granulosa cell tumor). The surface-binding autoradiographic study revealed that the binding sites for gonadotropins were localized in the stromal tissue. The results suggest that gonadotropic hormones may play a role in the growth and differentiation of a certain type of human ovarian neoplasms.

Trophoblastic Disease: Analysis of 342 Patients

The registry for trophoblastic disease in Wakayama, Japan was formed and 342 cases were analyzed. The total number of trophoblastic disease was 342 during 6 years (1972-1977). The number of hydatidiform moles, invasive moles, choriocarcinoma and transitional moles was 278 (81.3%), 28 (8.2%), 18 (5.3%) and 12 (3.5%), respectively. The greatest number of hydatidiform moles occurred in the range 25-29 years inclusive. The percentage of patients with hydatidiform moles over 45 years of age was significantly high. The incidence of malignant complications (invasive moles and choriocarcinoma) of hydatidiform moles was 16.5% in 284 molar pregnancies. The frequency of malignant complications was remarkably high in women over 40 years of age. Thus the epidemiologic study of trophoblastic disease might turn up some important data and the importance should be emphasized.

Ovarian Clear‐Cell Carcinoma Producing Estral and Human Chorionic Gonadotropin

A case of clear‐cell carcinoma of the ovary in a 52‐year‐old woman having an unusual menstrual history is presented. Serum concentrations of human chorionic gonadotropin (hCG) and estradiol were 120 mlU/ml and 86 pg/ml, respectively, while the serum FSH level was 43 mlU/ml. lmmunohistochemistry of the tumor revealed positive staining for both hCG and estradiol in the tumor cells.

Gonadotrophin Dependence of Steroidogenesis by Human Corpora lutea of Different Ages during the Menstrual Cycle

In vitro production of progesterone and estradiol by human corpora lutea of different ages was evaluated in the presence or absence of human chorionic gonadotrophin (HCG). Progesterone production by the luteal tissue was enhanced by as little as 0.1 IU/ml HCG and maximally stimulated by approximately 10 IU/ml HCG. Estradiol production was enhanced by 100 IU/ml HCG. Under control conditions, the synthetic activities of progesterone and estradiol were highest in the luteal tissue isolated from the mid-luteal phase corpora lutea and were lowest in the late luteal phase corpora lutea. The addition of HCG (100 IU/ml) stimulated progesterone and estradiol production by early and mid-luteal phase corpora lutea, whereas HCG had no effects on steroidogenesis by late luteal phase corpora lutea. The results suggest that the age of the corpus luteum might be an important factor governing luteal cell responsiveness to gonadotrophins.

Masked gonadotropin-binding sites in human corpora lutea during menstrual cycle and pregnancy

To evaluate the possible existence of masked receptors for luteinizing hormone (LH)/human chorionic gonadotropin (hCG) in the human corpus luteum, we examined the effect of neuraminidase pretreatment on the specific binding of (125I)hLH to luteal particulates obtained from 11 patients during the menstrual cycle and 4 patients during early pregnancy. The pretreatment with neuraminidase significantly enhanced the specific binding of hLH to corpora lutea at the different stages of the luteal phase. Scatchard analyses revealed that neuraminidase increased the number of LH binding sites without altering the affinity for LH. Furthermore, the specific binding of hLH to human corpora lutea during pregnancy significantly increased after the pretreatment with neuraminidase. The data suggest that distinct populations of receptors for LH/hCG are masked within the human luteal cells.

The effect of luteinizing hormone releasing hormone (LHRH) on steroidogenesis by the human luteal tissue.

The effect of luteinizing hormone releasing hormone (LHRH) on progesterone and estradiol production was studied in human luteal tissue. Tissue slices were incubated in Hams F‐10 medium under an atmosphere of 95% O2; 5% CO2 at 37 °C for 4 h. Slices were treated with or without human chorionic gonadotropin (HCG) in the presence or absence of LHRH. HCG stimulated progesterone and estradiol production by human luteal tissue in a time‐and dose‐related manner. LHRH stimulated the basal progesterone production in five (one early luteal and four mid‐luteal) of 17 corpora lutea, and stimulated the basal estradiol production in three (all mid‐luteal) of 16 corpora lutea. On the other hand, LHRH inhibited HCG–stimulated progesterone production in four (two early heal and two mid–luteal) of 22 corpora lutea. and inhibited HCG‐stimulated estradiol production in four (one early luteal and three mid‐luteal) of 18 corpora lutea. In the acute short‐term incubations of human luteal tissue, therefore, LHRH had little effect on basal and HCG‐stimulated steroidogenesis. However, in a few corpora lutea taken in the early or mid‐luteal phase, LHRH 5timulated basal steroidogenesis and inhibited HCG‐stimulated steroidogenesis.

Luteinizing hormone receptors in human ovarian follicles and corpora lutea during the menstrual cycle

The binding of 125I-labeled human luteinizing hormone (hLH) to the 2000-g fraction of human ovarian follicles and corpora lutea during the entire menstrual cycle was examined. Specific high affinity, low capacity receptors for hLH were demonstrated in the 2000-g fraction of both follicles and corpora lutea. Specific binding of 125I-labeled hLH to follicular tissue increased from the early follicular phase to the ovulatory phase. Specific binding of 125I-labeled hLH to luteal tissue increased from the early luteal phase to the midluteal phase and decreased towards the late luteal phase. The results of the present study indicate that the increase and decrease in receptors for hLH during the menstrual cycle might play an important role in the regulation of the ovarian cycle.

Effects of gonadotropin-releasing hormone and estrogen on serum levels of human chorionic gonadotropin-like substance in postmenopausal women

The present paper reports the serum levels of immunoreactive hCG or hCG-like substance and the effect of gonadotropin-releasing hormone (GnRH) and estrogen on GnRH immunoreactive hCG levels in postmenopausal women

Luteinizing Hormone Receptor Binding Inhibitor in Aqueous Extract of Human Corpus luteum

Aqueous extracts of human luteal tissue significantly inhibited binding of 125I-labelled human luteinizing hormone (LH) to the 2,000-g subcellular fraction of human corpora lutea. In contrast, aqueous extract of nonluteal tissue of the human ovary did not show a comparable activity to inhibit LH binding. Extracts of human corpus luteum had little or no ability to inhibit LH binding to porcine luteal homogenates. The inhibitory effect of the aqueous extract on LH binding to human luteal homogenate was demonstrated to be dose-related. The inhibitory effect of aqueous extracts of human corpora lutea on LH binding increased from the early to mid and late luteal phase of the menstrual cycle. The results of the present study suggest that there is an LH receptor binding inhibitor (LHRBI) in the 30,000-g aqueous extract of the human corpus luteum and the increase in LHRBI in the luteal tissue as the human corpus luteum ages may explain the means whereby the human corpus luteum regulates its own life span.