[1] Univ Concepcion, Fac Vet Sci, Lab Anim Physiol & Endocrinol, Chillan, Chile
[2] Univ Chile, Inst Biomed Sci, Santiago, Chile
[3] Free Univ Berlin, Inst Vet Biochem, D-1000 Berlin, Germany
[4] Univ Chile, Western Fac Med, Dept Internal Med, Lab Endocrinol & Metab, Santiago, Chile
[5] Univ Buenos Aires, Hosp Ninos R Gutierrez, Ctr Invest Endocrinol, Buenos Aires, DF, Argentina
[6] Univ Buenos Aires, Dept Histol, Buenos Aires, DF, Argentina