The trend of PRL and PRLR mRNA expression ( Figures 3 F and 3 I) was similar to that of hypothalamic VIP , which gradually increased with the duration of the experiment and showed a highly significant increase on d 27 and 45 ( P < 0.01).
Serum testosterone, FSH, and LH concentration showed a slight increase on d 13, followed by a sharp decrease on d 27 and 45 ( P < 0.01), while PRL concentrations were low on d 0 and 13, and increased rapidly on d 27 and 45 ( P < 0.01).The expression pattern of GnRH, FSH, LH, and THRβ mRNA were similar, with high levels on d 0 and 13 and a decreasing trend on d 27 and 45 ( P < 0.05 or P < 0.01); and GnRHR mRNA levels were higher on d 13 ( P < 0.05), but then had decreased by d 27 and 45 ( P < 0.01).