altrenogest and Hyperplasia

Altrenogest (ALT), a synthetic progestogen, and exogenous gonadotropins were administered to the Swine Leukocyte Antigen (SLA) inbred miniature pig that typically has a reduced ovulation rate and small litter size. In Study 1, 15 adult female pigs were either controls (Group I, n = 5), fed 15 mg ALT/day for 14 days (Group II, n = 5), or fed ALT and treated with pregnant mare's serum gonadotropin (1200 IU, i.m.) and human chorionic gonadotropin (500 IU, i.m.) 24 h and 104 h, respectively, after ALT withdrawal (Group III, n = 5). In Study 2, three groups of pigs (I, n = 24; II, n = 11; III, n = 11) were treated similarly to those in Study 1 except that pigs in Study 2 (Groups II and III) were mated. Ovaries of all animals in both studies were examined laparoscopically or by laparotomy 5-8 days after estrus to assess ovarian activity. The uteri of Group II and III animals in Study 2 were flushed with tissue culture medium, which was evaluated for the presence and quality of embryos. No pig demonstrated estrous behavior during ALT administration. Not all animals demonstrated typical estrous behavior after ALT withdrawal. When the data from both studies were combined, 2 of 16 (12.5%) of group II and 6 of 16 (37.5%) of Group III pigs failed to demonstrate standing estrus. Following ALT withdrawal, females in Groups II and III returned to estrus in 5.6 +/- 0.3 and 5.8 +/- 0.3 days, respectively (p greater than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Chorionic Gonadotropin; Embryo, Mammalian; Endometrium; Estrenes; Female; Gonadotropins, Equine; Hyperplasia; Major Histocompatibility Complex; Ovary; Pregnancy; Progesterone Congeners; Swine; Swine, Miniature; Trenbolone Acetate