Claudia Merkwitz

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The origin of fetal Leydig cells (FLC) and whether they share a common lineage with adult Leydig cells (ALC) is still under debate, and a marker to reliably track and isolate fetal Leydig precursor cells remains to be identified. We analyzed KIT positive (KIT+) cells in gonads from bovine fetuses with crown-rump-length (CRL) 2.5–85 cm by(More)
Obese melanocortin-4-receptor-deficient (MC4R-/-) male mice are reported to have erectile dysfunction, while homozygous MC4R-/- female mice are apparently fertile. A recently established obese mouse strain, carrying an inactivating mutation in the MC4R gene, revealed difficulties in breeding for the homozygous female mice. This prompted us to determine the(More)
BACKGROUND Controversial reports on prolactin receptors (PRL-R), the long and short form, on endothelial cells (EC) may be explained by the choice of EC derived from the micro- and macrovascular bed of either endocrine and non-endocrine organs. METHODS We studied here PRL-R expression in organs [bovine corpus luteum (CL), umbilical vein, aorta] and in(More)
KIT is a type III receptor protein tyrosine kinase, and KITL its cognate ligand. KIT can mediate its effects via several intracellular signalling pathways, or by formation of a cell-cell anchor with its ligand. Through these mechanisms, KIT controls fundamental cellular processes, including migration, proliferation, differentiation and survival. These(More)
Controversy remains regarding the origin of the pancreatic endocrine cells. It is generally accepted that the majority of insulin-secreting cells derive from the endodermal epithelium of the gastrointestinal tract. The aim of this study was to determine the contribution made by a particular cluster of differentiation (CD)-positive cells to the development(More)
In the corpus luteum (CL), blood vessels develop, stabilize, and regress. This process depends on the ratio of pro- and antiangiogenic factors, which change during the ovarian cycle. The present study focuses on the possible roles of 23,000 (23K) prolactin (PRL) in the bovine CL and its antiangiogenic NH(2)-terminal fragments after extracellular cleavage by(More)
Hematopoietic-like colonies develop in post-confluent granulosa cell cultures derived from bovine antral follicles. Previously, we had shown that these colonies gave rise to macrophages. In the present study, we validated the presence of somatic KIT-positive (KIT(+)) progenitor cells in colony-containing granulosa cell cultures. The cultures expressed the(More)
The protease cathepsin D (Cath D) and its proteolytically inactive proform, procathepsin D (ProCath D), turned out to be multifunctional within and outside the cell. Elevated levels of ProCath D occur in malignant tumors and in organs under chronic inflammation. One important source for this increase of ProCath D might be endothelial cells. Here we examined(More)
Islets form in the pancreas after the first endocrine cells have arisen as either single cells or small cell clusters in the epithelial cords. These cords constitute the developing pancreas in one of its earliest recognizable stages. Islet formation begins at the time the cords transform into a branching ductal system, continues while the ductal system(More)
Endocannabinoids exert numerous effects in the CNS under physiological and pathological conditions. The aim of the present study was to examine whether the endocannabinoid N-arachidonoyldopamine (NADA) may protect neurons in excitotoxically lesioned organotypic hippocampal slice cultures (OHSC). OHSC were excitotoxically lesioned by application of(More)