Thirty pregnant (experimental) and 17 nonpregnant (control) sexually mature female spotted skunks (Spilogale putorius latifrons) were bled twice monthly by cardiac puncture beginning in the middle of the 7-mo preimplantation period and continuing until just prior to nidation. The jugular vein of seven pregnant and four nonpregnant skunks was cannulated prior to implantation and blood drawn every 2 h until nidation. Three additional pregnant animals were sampled at 2-h intervals during middelay (January). Luteinizing hormone (LH) levels were determined by double antibody radioimmunoassay.

Peripheral plasma levels of LH in pregnant skunks were low at 120 days prior to nidation (4.9 ng/ml). Thereafter, mean LH levels gradually increased until nidation, at which time they fluctuated about a mean of 7.9 ng/ml. Plasma levels of LH in nonpregnant skunks were generally higher throughout the same period. The pattern of LH secretion in pregnant skunks did not appear to differ between midpreimplantation (January) and the week preceding nidation (late April) as determined by 2-h serial samples. No surge in LH was observed prior to nidation; however, peak and basal levels of LH were somewhat higher than in January. The gradual rise in LH secretion was paralleled by a similar rise in progesterone, thus suggesting that LH might have a direct and/or indirect role in initiating resumption of full luteal function and embryonic development.