EFFECT OF NEONATAL ALLYLESTRENOL TREATMENT (HORMONAL IMPRINTING) ON THE SERUM TESTOSTERONE AND PROGESTERONE CONCENTRATION IN ADULT-RAT

Serum testosterone concentration was significantly elevated in adult m ale rats by a single perinatal allylestrenol administration. One week after a second allylestrenol treatment in adulthood the hormone concen tration dropped below the control values. Serum progesterone concentra tion was significantly lowered in adult female rats by a single perina tal allylestrenol administration. Following a second allylestrenol tre atment in adulthood the hormone concentration reached the control valu es. These experiments demonstrate that the hormonal imprinting caused by allylestrenol (a steroid used in the treatment of endangered pregna ncy) not only acts at receptor level and produces changes in sexual be haviour, but also induces modifications in serum hormone concentration s.