Changes in serum testosterone concentrations in the male pig during development

Serum testosterone concentrations were elevated between 40 and 60 days p.c. but were low between 60 and 100 days p.c. when the testis descends. Elevated concentrations occurred in the perinatal period and from the 18th week after birth. Between 60 days p.c. and 16 weeks after birth the changes in serum testosterone concentrations parallel those of testicular development, as determined by morphology and steroid histochemistry, and peripheral LH concentrations.