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GnRH has been shown to play a role in the regulation of secretion of hCG by human placenta. Immunocytochemical studies have demonstrated the presence of the peptide, but do not address whether the GnRH is maternal, fetal, or placental in origin. In situ hybridization studies using a biotinylated pro-GnRH cDNA were, therefore, undertaken to determine the distribution of pro-GnRH mRNA in first trimester placental samples. Using an avidin-biotin-Cy.5 detection system in conjunction with laser scanning confocal microscopy, pro-GnRH mRNA was shown to be present in both the cytotrophoblast and syncytiotrophoblast cells of placental villi, although not in the cells of the fetal connective tissue. Prior hybridization with a 200-fold excess of unlabeled probe blocked hybridization of the labeled pro-GnRH probe. Southern and sequence analysis demonstrated that the probe hybridized to a transcript identical to hypothalamic GnRH. Immunocytochemical staining using an antiserum to amino acids 6-16 of pro-GnRH demonstrated the presence of translated pro-GnRH in both the cytotrophoblast and syncytiotrophoblast epithelia. We conclude that the synthesis of pro-GnRH by both the cytotrophoblast and the syncytiotrophoblast of human placenta is consistent with either an autocrine or a paracrine mode of GnRH regulation of hCG secretion.

An immunocytochemical assay for estrogen receptor (ER) was used to study the distribution of receptor in fetal and immature female mouse reproductive tracts. Immunoblots confirmed that a single band, the size of the ER, immunostained in extracts from day 15 and 17 fetal reproductive tracts. Staining was observed over nuclei of epithelial cells of the Mullerian duct and over nuclei of cells of the developing connective tissue (mesenchymal cells) of the reproductive tract on fetal day 15. By day 17 when a primitive uterus could be distinguished, ERs were detected in nuclei of mesenchymal cells, but in only a small portion of epithelial cells. A different pattern of immunocytochemical staining was observed in uteri from animals killed on the day of birth; cells of the connective tissue contained ER, but the epithelial cells did not. By 4 or 6 days after birth, more nuclei in the connective tissue stained for ER with a greater intensity compared to nuclear staining in epithelial cells. ERs were detectable in nuclei of both uterine epithelial cells and connective tissue cells on days 10 and 19 after birth.

Two patients with enlarged pituitary fossae presented with a number of features in their medical history and laboratory workup suggesting the diagnosis of “non-functioning” pituitary adenoma. Both patients had low serum thyroxine (T4) concentrations and resin T3 uptake, and one patient showed a high titer of microsomal thyroid antibodies. Both patients had high serum TSH concentrations before and after stimulation with TRH. After pituitary surgery, the serum TSH levels diminished but remained abnormally high and were suppressed by thyroid hormone administration. Light microscopic studies of the tumors, including differential staining and immunocytochemical procedures for the demonstration of TSH cells, showed cells indistinguishable from those of chromophobic adenomas. Ultrastructurally, the adenoma cells contained relatively few granules, similar to those described in “non-functioning” chromophobic tumors. Our investigations suggest that some of the patients diagnosed as having “non-functioning” pituitar...

The bovine fetal placenta expresses a family of PRL-related genes, consisting of the gene encoding bovine placental lactogen (bPL), and a diverse group of related genes, exemplified by bovine PRL-related cDNA I (bPRCI). bPL and the protein encoded by bPRCI are quite distinct from one another, predicting proteins only about 36% similar in amino acid sequence. To identify the cells responsible for the expression of bPL and bPRCI, in situ hybridization experiments were performed. 35S-Labeled RNA probes were prepared from the 3' regions of bPL and bPRCI and allowed to hybridize to frozen sections of bovine placentomes. Transcripts corresponding to bPL and bPRCI colocalized to fetal binucleate cells, which is consistent with the immunocytochemical localization of bPL. Signal from radiolabeled antisense strand probe was blocked by pretreatment of the sections with a 150-fold excess of unlabeled probe, but not by an excess of unlabeled probe prepared using the other cDNA as a template. This demonstrated that the signals observed were specific for bPL and bPRCI and that the two probes did not cross-hybridize at the stringency of our conditions. Radiolabeled sense strand probes yielded no signal. We conclude that the binucleate cells of the bovine placenta transcribe at least two members of the PRL gene family that may influence fetal development and maternal adaptation to pregnancy.

The intracellular fate of a radiolabeled GnRH agonist ([D-Ala6]des-Gly10-GnRH ethylamide) taken up by rat pituitary gonadotrophs in vivo was determined by quantitative electron microscopic autoradiography. Rats ovariectomized for 2 weeks were given intracarotid injections of the ligand, and pituitary glands were removed, counted, and processed for electron microscopic autoradiography at specific intervals thereafter. Uptake of the GnRH agonist by the pituitary was specific, since simultaneous administration of the radiolabeled peptide and a 200-fold excess of the unlabeled peptide inhibited binding by greater than 90%. A simple grain density (GD) analysis of autoradiograms revealed six cell compartments to be significantly labeled (GD > 1): plasma membrane, vesicles, lysosomes, Golgi elements, nuclear membrane, and secretory granules. Four of these (plasma membrane, vesicles, lysosomes, and Golgi elements) showed distinct changes in the pattern of labeling with time: 5 min after the injection, the greates...