Poly(ADP-ribosyl)ation of proteins and germ cell development in hyperthyroid rat testes.
The effect of increased serum levels of thyroid hormone (triiodothyronine, T3) on young rat testis spermatogenesis was studied by analysing molecular and morphological parameters. Hyperthyroidism was induced by either T3-treatment or 2- and 10-day cold exposure. The poly(ADP-ribosyl)ation of proteins catalysed by poly(ADP-ribose) polymerase, which is particularly active at specific stages of rat spermatogenesis, was analysed as molecular index of DNA damage and cell stress. Poly(ADP-ribose) polymerase activity rose after both T3-treatment and 2- and 10-day cold exposure, with a trend of 10-day cold-exposed rats towards control values. In all hyperthyroid rats poly(ADP-ribose) turnover, as a contribution of both poly(ADP-ribose) polymerase and poly(ADP-ribose) glycohydrolase), was enhanced with respect to euthyroid animals. Poly(ADP-ribosyl)ation of proteins occurred with long and branched polymers suggesting an increased involvement of the modification system in DNA repair. Morphological changes of germ tissue were observed in hyperthyroid rats, mainly a high reduction of mature cells in the seminiferous tubule, and evidence of germ cell apoptosis was obtained by TUNEL method. In control animals germ cell apoptosis was within physiological levels. Conversely, in hyperthyroid rats a dramatic increase in the number of TUNEL-positive cells (some spermatogonia and numerous primary spermatocytes) was found, even though the increase was lower in 10-day than in 2-day cold-exposed animals.
Faraone-Mennella
Maria Rosaria
MR
Dipartimento di Biologia Strutturale e Funzionale, Facoltà di Scienze MM FF NN, Università degli studi di Napoli Federico II, Via Cinthia, 80126, Naples, Italy. faraone@unina.it
Ferone
Angela
A
Marino
Lucia
L
Cardone
Anna
A
Comitato
Raffaella
R
Venditti
Paola
P
Di Meo
Sergio
S
Farina
Benedetta
B
D000818:Animals; D017209:Apoptosis / Q000502:physiology; D003080:Cold Temperature; D006026:Glycoside Hydrolases / Q000378:metabolism; D006980:Hyperthyroidism / Q000378:metabolism* / Q000503:physiopathology; D020287:In Situ Nick-End Labeling; D008297:Male; D009687:Nuclear Proteins / Q000378:metabolism*; D011064:Poly Adenosine Diphosphate Ribose / Q000378:metabolism*; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013090:Spermatocytes / Q000187:drug effects / Q000502:physiology; D013091:Spermatogenesis / Q000187:drug effects* / Q000502:physiology; D013737:Testis / Q000187:drug effects / Q000502:physiology; D013961:Thyroid Gland / Q000378:metabolism; D014284:Triiodothyronine / Q000494:pharmacology*
D009687:Nuclear Proteins; D014284:Triiodothyronine; D011064:Poly Adenosine Diphosphate Ribose; D011065:Poly(ADP-ribose) Polymerases; D006026:Glycoside Hydrolases; C022407:poly ADP-ribose glycohydrolase