Alcohol before puberty produces an advance in the onset of sexual behavior in male rats.

The effect of alcohol consumption before puberty on the development of genital-grooming (GG) and on the onset of sexual behavior was assessed. Wistar male rats were continuously exposed in a one-bottle access situation to either 6% ethanol (alcohol group, AG), an isocaloric sweetened solution (vehicle group, VG) or were maintained in standard laboratory conditions (control group, CG). Each solution was the only available liquid in each group from weaning (22 days) to 40 days of age. GG behavior was recorded from 25 to 47 days of age and sexual behavior was recorded from 42 to 74 days of age. The age at the maximum peak of both frequency and duration of GG showed an advance in the AG (33-35 days of age) compared with the CG (45 days) and the VG (47 days). An advance in the onset of sexual behavior was observed in the AG: at 46 days of age, seven of the nine males of this group showed ejaculatory behavior. In contrast, in the CG and VG, ejaculation occurred in at least 50% of subjects after 58 days of age. Regardless of the advance in the onset of sexual behavior, the characteristics of the different parameters of the copulatory sequence were not impaired by alcohol. The apparent advance in the onset of puberty is discussed in terms of the opioid hypothalamic activity as a mechanism that affects the LH secretion.