title: Distinct testicular steroidogenic response mechanisms between neonatal and adult heat-acclimated male rats.
abstract: BACKGROUND
  In comparison to short-term gonad heat exposure, little is known about the molecular mechanisms that regulate testicular steroidogenesis during long-term whole body heat acclimation.
  
  
  METHODS
  Testicular slices from neonatal (NHA) and adult (AHA) heat-acclimated Wistar rats were analysed in vitro to assess the mRNA expression and enzymatic activity of steroidogenic enzymes under basal and luteinising hormone (LH) or prolactin (PRL) stimulated conditions compared with control rats (CR). Furthermore, a de-acclimated group (DA) was created by transferring adult NHA rats to control conditions.
  
  
  RESULTS
  Heat acclimation significantly increased plasma LH levels in the AHA group and LH and PRL in the NHA group compared with the CR group; however, after heat acclimation, the T and E2 levels did not differ from the control levels. All heat-acclimated groups showed high basal intra-testicular steroid production in vitro. Moreover, basal Cyp11a1 and Hsd3b1 levels were upregulated in vitro in the NHA and DA groups versus the CR group. LH in vitro stimulation upregulated Cyp11a1 expression in the NHA and AHA groups and PRL stimulation upregulated Cyp17a1 levels in the NHA and DA groups compared with the basal expression levels. In the AHA group, decreased basal Star and CYP11A activities but increased HSD3B1 and CYP17A1 activities were found.
  
  
  CONCLUSIONS
  Our data revealed that despite the similar steroid levels in plasma and secreted in vitro by neonatal and adult heat-acclimated rat testicular slices, the molecular mechanisms underlying the steroidogenic response to heat acclimation during these different developmental stages were distinct.
authors.affiliation: Department of Animal Physiology, University of Warmia and Mazury in Olsztyn, Olsztyn, Poland.
authors.forename: Beata
authors.initials: B
authors.lastname: Kurowicka
authors.forename: Marcin
authors.initials: M
authors.lastname: Chrusciel
authors.forename: Agata
authors.initials: A
authors.lastname: Zmijewska
authors.forename: Milena
authors.initials: M
authors.lastname: Doroszko
authors.forename: Genowefa
authors.initials: G
authors.lastname: Kotwica
authors.forename: Nafis A
authors.initials: NA
authors.lastname: Rahman
mesh_terms: D000818:Animals; D002786:Cholesterol Side-Chain Cleavage Enzyme / Q000235:genetics / Q000378:metabolism; D007986:Luteinizing Hormone / Q000097:blood / Q000494:pharmacology; D008297:Male; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D011375:Progesterone Reductase / Q000235:genetics / Q000378:metabolism; D011388:Prolactin / Q000097:blood / Q000494:pharmacology; D011863:Radioimmunoassay; D051381:Rats; D017208:Rats, Wistar; D013696:Temperature; D013737:Testis / Q000378:metabolism*; D013739:Testosterone / Q000097:blood; D015854:Up-Regulation / Q000187:drug effects; D000098682:Steroidogenic Acute Regulatory Protein
chemical_list: D010750:Phosphoproteins; D000098682:Steroidogenic Acute Regulatory Protein; D013739:Testosterone; D011388:Prolactin; D007986:Luteinizing Hormone; D011375:Progesterone Reductase; D002786:Cholesterol Side-Chain Cleavage Enzyme