Effect of chronic treatment with Rosiglitazone on Leydig cell steroidogenesis in rats: in vivo and ex vivo studies.
BACKGROUND
The present study was designed to examine the effect of chronic treatment with rosiglitazone - thiazolidinedione used in the treatment of type 2 diabetes mellitus for its insulin sensitizing effects - on the Leydig cell steroidogenic capacity and expression of the steroidogenic acute regulatory protein (StAR) and cholesterol side-chain cleavage enzyme (P450scc) in normal adult rats.


METHODS
Twelve adult male Wistar rats were treated with rosiglitazone (5 mg/kg) administered by gavage for 15 days. Twelve control animals were treated with the vehicle. The ability of rosiglitazone to directly affect the production of testosterone by Leydig cells ex vivo was evaluated using isolated Leydig cells from rosiglitazone-treated rats. Testosterone production was induced either by activators of the cAMP/PKA pathway (hCG and dbcAMP) or substrates of steroidogenesis [22(R)-hydroxy-cholesterol (22(R)-OH-C), which is a substrate for the P450scc enzyme, and pregnenolone, which is the product of the P450scc-catalyzed step]. Testosterone in plasma and in incubation medium was measured by radioimmunoassay. The StAR and P450scc expression was detected by immunocytochemistry.


RESULTS
The levels of total circulating testosterone were not altered by rosiglitazone treatment. A decrease in basal or induced testosterone production occurred in the Leydig cells of rosiglitazone-treated rats. The ultrastructural and immunocytochemical analysis of Leydig cells from rosiglitazone-treated rats revealed cells with characteristics of increased activity as well as increased StAR and P450scc expression, which are key proteins in androgen biosynthesis. However, a number of rosiglitazone-treated cells exhibited significant mitochondrial damage.


CONCLUSIONS
The results revealed that the Leydig cells from rosiglitazone-treated rats showed significant reduction in testosterone production under basal, hCG/dbcAMP- or 22 (R)-OH-C/pregnenolone-induced conditions, although increased labeling of StAR and P450scc was detected in these cells by immunocytochemistry. The ultrastructural study suggested that the lower levels of testosterone produced by these cells could be due to mitochondrial damage induced by rosiglitazone.
Department of Morphology and Physiology, Universidade Federal Rural de Pernambuco, Recife, 52.171-900, Brazil.
Janaína A
JA
Couto
Karina L A
KL
Saraiva
Cleiton D
CD
Barros
Daniel P
DP
Udrisar
Christina A
CA
Peixoto
Juliany S B César
JS
Vieira
Maria C
MC
Lima
Suely L
SL
Galdino
Ivan R
IR
Pitta
Maria I
MI
Wanderley
D000818:Animals; D001835:Body Weight / Q000187:drug effects; D002478:Cells, Cultured; D002786:Cholesterol Side-Chain Cleavage Enzyme / Q000378:metabolism; D004353:Drug Evaluation, Preclinical; D007004:Hypoglycemic Agents / Q000009:adverse effects / Q000494:pharmacology; D007985:Leydig Cells / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D008297:Male; D009929:Organ Size / Q000187:drug effects; D010750:Phosphoproteins / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D000077154:Rosiglitazone; D012669:Seminal Vesicles / Q000166:cytology / Q000187:drug effects; D013256:Steroids / Q000096:biosynthesis*; D013737:Testis / Q000166:cytology / Q000187:drug effects; D013739:Testosterone / Q000097:blood; D045162:Thiazolidinediones / Q000009:adverse effects / Q000494:pharmacology*; D013997:Time Factors; D000098682:Steroidogenic Acute Regulatory Protein
D007004:Hypoglycemic Agents; D010750:Phosphoproteins; D013256:Steroids; D045162:Thiazolidinediones; D000098682:Steroidogenic Acute Regulatory Protein; D000077154:Rosiglitazone; D013739:Testosterone; D002786:Cholesterol Side-Chain Cleavage Enzyme