Cellular composition of the human pituitary pars tuberalis as revealed by immunocytochemistry

Summary An attempt was made to determine if any of the specialized secretory cell types common to the pars distalis also occur in the pars tuberalis of the human hypophysis. Available for study were 18 specimens of the inferior pars tuberalis, which partially surrounds the infundibular stem, and 3 specimens of the superior pars tuberalis that is attached to the median eminence. Antisera to human somatotropin, mammotropin, chorionic gonadotropin, follicle-stimulating hormone, FSH , luteinizing hormone, LH , thyrotropin, TSH , as well as to ^1–24-corticotropin, porcine ^17–39-corticotropin, and ovine LH were used with the Sternberger peroxidase-antiperoxidase immunocytochemical procedure to identify the probable cells of origin for these hormones.The evidence indicated that gonadotropic cells constitute the major portion of the parenchymal cell population in the pars tuberalis. They occurred throughout all of the pars tuberalis and were usually arranged in clusters. Somatotropic, mammotropic, corticotropic, and thyrotropic cells were rare and not found in all specimens. When present, they often formed a common group suggesting that their occurrence in the pars tuberalis resulted from displacement of primordial tissue of the pars distalis during embryogenesis.Supported in part by research grants HD-03159 and HD-08333 from the National Institute for Child Health and Human DevelopmentWe thank Dr. L.A. Sternberger for providing the PAP complex and others for antisera (Table 2) and hormones (Footnote 2) as listed     

Nuclear uptake and retention of androgen by the pituitary gland of the hamster and the rat

Summary Castrated adult male hamsters and castrated adult female rats were injected with either 0.2 g (hamsters) or 0.5 g (rats) of ³H-dihydrotestosterone (107 Ci/mmole)/100 grams body weight and killed 11/2 h later. The pituitary glands were removed and processed for both autoradiography and immunocytochemistry (hamster) or only autoradiography (rats). Localization of the androgen was found in 10–15% of the cells of the pars distalis in both species. Only cells that stained for luteinizing hormone (LH) in the hamster's pars distalis concentrated the androgen. Also cells in both the pars intermedia and pars nervosa (1–5%) concentrated the androgen in both species. Although the number of cells that concentrated the androgen in the pars intermedia and pars nervosa was small, this finding may be related to recent physiologic data that suggest that the gonadal steroids may play a role in regulating water retention and natriuresis.This study was supported by USPHS Research Career Development Award KO4NS0000164 (P.J. Sheridan) and USPHS Grants No. 1 RO1 NS12933, P30 HD10202 and HD 10914     

Responses of the teleost pituitary (goldfish,eel) to deionized water

Summary The cytological responses of the pituitary gland during adaptation to deionized water (DW) were investigated in the goldfish and the eel. In both teleost species, a stimulation of the prolactin (PRL) cells could not be detected, although the levels of blood electrolytes (Na⁺,Ca²⁺,Cl^–) are reduced in the eel. PRL cells appear less active in DW-adapted eels. A striking stimulation of the PAS-positive cells of the pars intermedia occurs in both species after 3 weeks and, in the eel, is still present after 11 weeks. Cell and nuclear hypertrophy, mitoses and a well-developed endoplasmic reticulum are observed. MSH cells are partially degranulated when pigmentation is affected; a reduced activity of MSH cells is evident after 11 weeks. The amount of neurohypophysial tissue is reduced. In the goldfish and the eel, during adaptation to DW, an unknown factor secreted by the PAS-positive cells of the pars intermedia appears to play a more important role than the secretion of PRL. These two species are able to survive in fresh water without the pituitary. The control of the PAS-positive cells by external sodium or calcium is discussed.     

Structural relationships between parenchymal and stromal elements in the pars intermedia of the rat adenohypophysis as demonstrated by extracellular space markers

Summary The pars intermedia (PI) of the rat adenohypophysis was studied by light and transmission electron microscopy after conventional staining as well as ruthenium red staining, and after systemic injection of horseradish peroxidase. The studies disclose a complex and constant system of two channel types (Type I and Type II channels) formed by PI cells with specific relationships to a very rich nerve supply, to each other, and to a stellate cell type proposed here to represent an element of neuroglia. The channel system could perform a function in the movement of fluids and solutes within the PI which is virtually avascular in the rat as well as in other mammals.Supported by the Medical Research Council of Canada Grant # MA6445We thank Mr. J. Jones and Mr. A.R. Morris for their expert technical assistance     

Localization of thyrotropin (TSH) in the dog pituitary gland

Summary Using the immunoperoxidase technique and antisera to the specific beta () subunits of bovine and rat TSH¹, selective immunocytochemical staining was localized in a specific cell population in the pars distalis of the dog pituitary gland. These TSH cells were found to be positive to aldehyde fuchsin, alcian blue, periodic acid-Schiff (PAS) and aniline blue. With the performic acidalcian blue (pH 0.2) -PAS-orange G procedure these cells stained blue-purple, demonstrating FSH/LH cells (blue or turquoise), ACTH/MSH cells (redpurple) and PRL cells (orange-red). The TSH cells were further differentiated from other functional cell types of the pars distalis on the basis of their typical cytological features, intraglandular distribution and by immunocytochemical double staining. In the pars distalis of adult male dogs the TSH cells were mostly shown to be smaller in size and less numerous than in bitches in the anestrous phase of the sexual cycle. Moreover, cytological alterations in the immunoreactive thyrotrophs in the pituitary of male and female dogs generally paralleled the spontaneous changes in thyroid function associated with thyroid atrophy and/or pituitary insufficiency, and thyroid hyperplasia or goiter. In conclusion, because of their specificity and high potency, the antisera to the -subunits of bovine and rat TSH represent an effective tool for the selective immunocytochemical localization of TSH in the dog pituitary. This allows the study of the morphology and function of TSH cells under different physiological, pathological and experimental conditions.Abbreviations for Hormones cited in this Paper ACTH Adrenocorticotropin - FSH Follicle Stimulating Hormone - GH Growth Hormone - LH Luteinizing Hormone - MSH Melanocyte Stimulating Hormone - PRL Prolactin - TSH Thyrotropin - TRH TSH Releasing Hormone - CG Chorionic Gonadotropin The authors are grateful to Mrs. B. Schilk and Miss U. Tüshaus for their excellent technical assistance     

Effects of tumors on the daily mitotic activity of mouse pars intermedia

We have investigated the effects of EA21a and EA34 mammary carcinomas on daily PI cell proliferation in mice. Animals were divided into groups grafted with either EA34 or EA21a carcinomas (and a non-grafted control group). They were all injected intraperitoneally with 2 microg colchicine per g of body weight 4 h before sacrifice and the number of mitoses per 1000 nuclei was calculated. The mitotic index (MI) of pars-intermedia epithelial cells in control animals showed significant temporal variations. However, the MI from mice grafted with EA34 or EA21a carcinomas showed no such variation. There was no difference between the daily MIs of controls and tumor grafted groups. The absence of a 24 h mitotic activity curve in both EA21a and EA34 tumor-bearing animals demonstrates a lower level of synchronization of cells entering mitosis.     

中间锦鸡儿CibHLH027基因的克隆和功能研究

叶片衰老是植物生长发育的最后阶段,黑暗、干旱和极端温度等会加速叶片衰老过程,严重影响植物的生长发育和作物产量。bHLH(basic helix-loop-helix)属于转录调控因子中的一个大家族,因具有保守性较高的bHLH结构域而得名,广泛存在于真核生物界。在中间锦鸡儿(Caragana intermedia)转录组数据库中得到一条候选bHLH基因全长序列,将其命名为Cib HLH027。正常和黑暗诱导的情况下,CibHLH027-OE株系较WT相比叶片衰老明显,并且黑暗处理后叶绿素含量下降、离子渗透率增大、细胞膜受损严重,说明CibHLH027参与了叶片衰老调控过程。     

Species-specificity of monoclonal antibodies recognising Prevotella intermedia and Prevotella nigrescens

Abstract Prevotella intermedia and Prevotella nigrescens are not easily distinguished, making it difficult to assess their roles in disease. This study examined the specificity of three monoclonal antibodies (mAbs) for these species. Differentiation between P. intermedia (13 isolates) and P. nigrescens (24 isolates) was by the electrophoretic mobility of their malate and glutamate dehydrogenase enzymes or by DNA homology grouping. All P. intermedia reacted strongly with mAb 40BI3.2.2 whereas P. nigrescens strains did not. Monoclonal antibodies 37BI6.1 and 39BI1.1.2 recognised all strains of both species but most P. nigrescens reacted weakly with mAb 39BI1.1.2. Monoclonal antibody 40BI3.2.2 therefore recognises an antigen specific for P. intermedia but not P. nigrescens and provides an easy and reliable means of distinguishing between these species. Three vaginal isolates identified biochemically as P. intermedia had enzymes with mobilities corresponding to neither P. intermedia nor P. nigrescens . These isolates were not recognised by mAbs 39BI1.1.2 or 40BI3.2.2 and may represent an undescribed taxon within this group of organisms.     

Expression of the α-subunit of glycoprotein hormones in the pars tuberalis-specific glandular cells in rat,mouse and guinea-pig

The nature of the hormone(s) secreted by the pars tuberalis (PT) is still unknown. This pituitary lobe is mainly formed by specific glandular cells that differ in their ultrastructural features from the other adenohypophysial cell types. Data from the literature indicate the presence of thyroid-stimulating hormone immunoreactivity in the PT-specific cells of the rat and the Djungarian hamster but not of other species, including the mouse and guinea-pig. The PT also encloses variable numbers of pars distalis cells, essentially gonadotrophs that are mainly dispersed in its caudal area. We studied the expression of the glycoprotein hormone -subunit in the PT of the rat, mouse and guinea-pig by in situ hybridization and immunocytochemistry. In situ hybridization, using an oligonucleotide probe complementary to rat cDNA sequence 196–237 revealed the expression of the -subunit gene throughout the PT of the rat and the mouse; in the guinea-pig, the probe labelled no pituitary cells. Light-and electron-microscopic immunocytochemistry demonstrated -subunit immunoreactivity in the secretory granules of the PT-specific cells in the three species examined. These cells did not react with a specific antibody against the -subunit of luteinizing hormone, an antibody that labelled scattered gonadotrops. The present data suggest that hormone(s) produced by the PT-specific glandular cells are, at least partly, related to glycoprotein hormones.