Involvement of lipids in dimethoate-induced inhibition of testosterone biosynthesis in rat interstitial cells.
The mechanism involved in the inhibition of testosterone (Te) biosynthesis after a sub-chronic exposure to low doses of dimethoate (D) was studied in rat interstitial cells (IC). Expression of COX-2 in IC isolated from D-treated rats increased by 44% over C data, while transcription of StAR decreased by approx. 50% and the expression of this protein was diminished by approximately 40%. PGE(2) and PGF(2alpha) were increased by 61 and 78%, respectively. Te concentration decreased by 49% in IC homogenates. Concomitantly, plasma concentration of LH and FSH both increased. Araquidonate (ARA) and C(22) fatty acyl chains in phospholipids from IC mitochondrial fraction decreased by approx. 30% after D treatment. Protein carbonyls, lipoperoxides and nitrite content increased while alpha-tocopherol and the antioxidant capacity of the soluble cellular fraction decreased significantly. Stimulation with h-CG 10 nM overnight failed to overcome the inhibition caused by D on both Te biosynthesis and 3beta- and 17beta-hydroxysteroid dehydrogenases. Decreased Te biosynthesis may be attributed to (1) inhibition of StAR protein activity due to the stimulation of COX-2 and the overproduction of PGF(2alpha), (2) decreased stimulatory effect of ARA on StAR with a subsequent reduction in the availability of CHO for the androgenic pathway, and/or (3) indirect inhibition of steroidogenic enzymes by a lower transcriptional rate caused by elevated PGF(2alpha). Rofecoxib administration prevents the deleterious effect(s) exerted by D.
Astiz
Mariana
M
Instituto de Investigaciones Bioquímicas de La Plata, CCT La Plata, CONICET-UNLP, Cátedra de Bioquímica y Biología Molecular, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, Calles 60 y 120, La Plata, Argentina.
Hurtado de Catalfo
Graciela E
GE
de Alaniz
María J T
MJ
Marra
Carlos Alberto
CA
D000818:Animals; D001835:Body Weight / Q000187:drug effects; D002478:Cells, Cultured; D002800:Cholinesterase Inhibitors / Q000494:pharmacology; D051546:Cyclooxygenase 2 / Q000235:genetics / Q000378:metabolism; D004117:Dimethoate / Q000494:pharmacology*; D015536:Down-Regulation / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects; D048788:Growth and Development / Q000187:drug effects; D007306:Insecticides / Q000494:pharmacology; D007985:Leydig Cells / Q000187:drug effects* / Q000378:metabolism; D008055:Lipids / Q000494:pharmacology*; D008297:Male; D018384:Oxidative Stress / Q000187:drug effects; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013739:Testosterone / Q000096:biosynthesis*; D000098682:Steroidogenic Acute Regulatory Protein
D002800:Cholinesterase Inhibitors; D007306:Insecticides; D008055:Lipids; D010750:Phosphoproteins; D000098682:Steroidogenic Acute Regulatory Protein; D013739:Testosterone; D051546:Cyclooxygenase 2; D004117:Dimethoate