title: Corpora lutea of pregnant and pseudopregnant domestic cats reveal similar steroidogenic capacities during the luteal life span.
abstract: In domestic cats, luteal phases of pregnancy and pseudopregnancy (non-pregnant luteal phase) differ in the course and level of plasma progesterone (P4). Therefore, we assumed differences in luteal steroidogenic capacities. Here we present a comprehensive analysis of intraluteal steroid biogenesis in the domestic cat. We quantitatively measured relative mRNA levels of steroidogenic acute regulatory protein (STAR), cytochrome P450 oxidases (CYP), hydroxysteroid dehydrogenases (HSD), steroid reductase (SRD) and enzymes involved in sulfoconjugation of steroids, i.e. sulfotransferase (SULT) and sulfatase (STS). Protein expression was analysed by Western Blot for HSD3B. Additionally, intraluteal steroid contents were determined. During the pseudopregnant luteal phase, expression of STAR (p=0.005), HSD3B1 (p<0.0001), CYP19A1 (p<0.0001) and HSD17B7 (p=0.008) decreased from formation of the corpus luteum (CL) onwards. HSD3B protein expression was highest in the development/maintenance stage of CL and declined during the subsequent luteal phase of pregnancy and pseudopregnancy. This was in accordance with decreasing intraluteal levels of P4, oestrogens and androgens. In contrast, expression of SRD5A1 (p<0.001) increased with progression through stages of the pseudopregnant CL, being indicative of P4 metabolism via an alternate pathway to dihydrotestosterone (DHT). Compared to the formation stage, expression of SULT1E1 was higher in all other luteal stages of pseudopregnancy (p=0.004), implying a potential sulfoconjugation of oestrogens. Expression of CYP11A1 and CYP17A1 was unaffected by the luteal stage (p>0.05), suggesting a permanent capacity of cat CL to convert progestogens via androgen and oestrogen pathways. In general, mRNA expression profiles of steroidogenic enzymes during the pregnant luteal phase reflected the pseudopregnancy profiles. Intraluteal oestrogen (p<0.0001) and androgen (p=0.008) levels were higher in the formation stage compared to the following luteal stages of pseudopregnancy. Concentrations of P4 were higher in the development/maintenance compared to the regression stages (p=0.01). We conclude that cat CL of the same histomorphological stage are characterised by identical steroidogenic capacities independently of an on-going pregnancy.
authors.affiliation: Leibniz Institute for Zoo and Wildlife Research, Department of Reproduction Biology, PF700430, 10324 Berlin, Germany. Electronic address: zschockelt@izw-berlin.de.
authors.forename: Lina
authors.initials: L
authors.lastname: Zschockelt
authors.affiliation: Leibniz Institute for Zoo and Wildlife Research, Department of Reproduction Biology, PF700430, 10324 Berlin, Germany. Electronic address: amelkina@izw-berlin.de.
authors.forename: Olga
authors.initials: O
authors.lastname: Amelkina
authors.affiliation: Institute of Animal Reproduction and Food Research of the Polish Academy of Sciences, Department of Reproductive Immunology and Pathology, Tuwima Street, Olsztyn 10-748, Poland. Electronic address: m.siemieniuch@pan.olsztyn.pl.
authors.forename: Marta J
authors.initials: MJ
authors.lastname: Siemieniuch
authors.affiliation: Leibniz Institute for Zoo and Wildlife Research, Department of Reproduction Biology, PF700430, 10324 Berlin, Germany. Electronic address: stefanie.koster88@gmail.com.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Koster
authors.affiliation: Leibniz Institute for Zoo and Wildlife Research, Department of Reproduction Biology, PF700430, 10324 Berlin, Germany. Electronic address: jewgenow@izw-berlin.de.
authors.forename: Katarina
authors.initials: K
authors.lastname: Jewgenow
authors.affiliation: Leibniz Institute for Zoo and Wildlife Research, Department of Reproduction Biology, PF700430, 10324 Berlin, Germany. Electronic address: braun@izw-berlin.de.
authors.forename: Beate C
authors.initials: BC
authors.lastname: Braun
mesh_terms: D013741:3-Oxo-5-alpha-Steroid 4-Dehydrogenase / Q000235:genetics; D000818:Animals; D001141:Aromatase / Q000235:genetics; D001483:Base Sequence; D002415:Cats / Q000378:metabolism*; D018797:Cell Cycle Proteins / Q000235:genetics; D003338:Corpus Luteum / Q000378:metabolism*; D005260:Female; D008565:Membrane Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000235:genetics / Q000378:metabolism; D010750:Phosphoproteins / Q000235:genetics; D011247:Pregnancy / Q000378:metabolism*; D011375:Progesterone Reductase / Q000235:genetics / Q000378:metabolism; D009418:S100 Proteins / Q000235:genetics; D017422:Sequence Analysis, DNA; D013251:Steroid Isomerases / Q000235:genetics / Q000378:metabolism; D015238:Sulfotransferases / Q000235:genetics; D000098682:Steroidogenic Acute Regulatory Protein
chemical_list: C021425:3 beta-hydroxysteroid oxidoreductase-delta(5) 3-ketosteroid isomerase; D018797:Cell Cycle Proteins; D008565:Membrane Proteins; D009097:Multienzyme Complexes; D010750:Phosphoproteins; D009418:S100 Proteins; D000098682:Steroidogenic Acute Regulatory Protein; D011375:Progesterone Reductase; D001141:Aromatase; D013741:3-Oxo-5-alpha-Steroid 4-Dehydrogenase; D015238:Sulfotransferases; C020122:estrone sulfotransferase; D013251:Steroid Isomerases
keywords: Corpus luteum; Felis catus; Pregnancy; Pseudopregnancy; Steroid hormone; Steroidogenic enzyme