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Rats bearing pituitary autotransplants received injections of luteinizing hormone (LH) for 9 days or human chorionic gonadotrophin (HCG) for 6 days. Both compounds caused significant increases in ovarian and uterine weights as well as vaginal mucification, observed 1 day after the last injection. Luteal regression and a decrease in uterine weight compared to control animals were observed 35 days after final injection with each compound. Continuous dioestrous vaginal smears were observed in all groups. In hypophysectomized rats, HCG, but not LH, caused an increase in ovarian weight which was statistically significant on the day after the final injection in one of two experiments. Uterine weights were increased after LH and HCG treatments. Vaginal cornification was evident 3\p=n-\4 days after initiation of treatment with either hormone. When ovariectomy preceded hypophysectomy, there was no increase in uterine weight and no vaginal cornification in response to HCG treatment indicating the essential role of the ovaries. The effects in rats bearing auto-transplanted pituitaries as well as in hypophysectomized rats are attributed to the stimulation of oestrogen secretion from the ovaries. It is suggested that the rapid rate of luteal regression in rats bearing transplanted pituitaries is initiated by an increase in metabolic activities due to LH or HCG.

Tiamulin was compared, under a variety of experimental conditions, with 4 water-soluble antibiotic preparations available commercially for the control and treatment of mycoplasmal infections in poultry. In chickens, tiamulin was more effective than the reference antibiotics in preventing and eradicating airsacculitis caused by Mycoplasma gallisepticum and preventing airsacculitis and synovitis caused by M. synoviae. In turkeys, tiamulin and tylosin were equally active in preventing airsacculitis caused by M. gallisepticum. Tiamulin was highly effective in preventing airsacculitis also when administered as a single subcutaneous dose.

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