THE EFFECT OF PROSTAGLANDIN F2ALFA ON FALSE PREGNANCY IN BITCHES RENATO CAMPANARUTBARNABE Professor Adjunto AISSÉ MUCCIOLO Médico Veterinário ANTONIO MATERA Professor Livre-Docente PAULO SÉRGIO DE MORAES BARROS Auxiliar de Ensino RAUL GASTÃO MUCCIOLO Professor Livre- Docente Faculdade de Medicina Veterinária e Zootecnia da USP BARNABE, R.C.; MUCCIOLO, A.; MATERA, A.; BARROS, P.S. M.; MUCCIOLO, R.G. The effect of prostaglandin F2alifa on false pregnancy in bitches. Rev.Fac.Med.vet.Zootec.Univ.S. Paulo, 16(1/2): 25-26, 1979 SUMMARY: The property of Prostaglandin F2alfa Tham-salt to in - duce functional regression of the corpus luteum was investigated in 40 clinically false pregnant bitches of various breed and age. PGF2 alfa was administered by subcutaneous injection of 0.5 mg, being ef- fective in 37 animals, but had to be repeated in 4 cases. Animals rea- ched normal behaviour in about 7 to 8 days after treatment. Vomi- ting and anorexy were observed in one bitch and sleepiness in as many three. The implications of the persistent corpora lutea in rela- tion to the luteolytic effect of PGF2alfa in false pregnant bitches is discussed. Results suggest that PGF2alfa could be used for termina- tion of clinical symptoms of canine false pregnancies. No methods of radioimmunoassay or competitive protein binding are available for LH and progesterone analyses. UNITERMS: False pregnancy*; PGF2alfa*; Bitch*. IN fKODUCTION False pregnancy is a condition described2 as “an intensification and prolongation of metoestrus in the bitch. The essential feature of the condition is the persistence of the corpora lutea in the ovaries.” On the other side, it has been suggested^ that PGF2alfa could be used for termination of unwanted canine pregnancies through an active luteolytic mechanisms. It was therefore felt that PGF2alfa could profitably be used for the suppression of pseudo-pregnancy in the bitch. Herein, we report the effect of subcutaneous injections of PGF2alfa on clinical signs of pseudo-pregnant bitches. MATERIALS AND METHODS Animals used for this study were of several different types and were obtained from several different sources. Breed, age, last heat and breeding history can be seen in Table 1. Clinical history revealed 8 bitches exhibiting mothering beha- viour to inanimate objects, 2 exhibiting labour pains, 15 bedmaking and one nursing a cat. Ten of the 40 bitches were reported as having several previous false pregnancy signs. At clinical examination 32 bitches presented galactorrhoea and 8 had mammary enlargement. Prostaglandin F2alfa-treated bitches received subcutaneous in - jections of 0.5 mg PGF2alfa THAM buffer solution* . PGF2alfa (100 mg) is dissolved in 10 ml of Tris-(hydroxy-methylaminoetha- ne) buffer (pH 8.2). RESULTS AND DISCUSSION In only 3 (no. 8220, 16387, 31605) of the 40 treated bitches, PGF2alfa did not cause regression of the symptoms of false pregnan- cy. In these cases, therapy was changed at the instance of the ow- ners. In the remaining bitches, galactorrhoea disappeared within 3 to 4 days, mammary enlargement decreased after 5 to 6 days and symptoms of false pregnancy quickly vanished in all but four cases (no. 12126, 16387, 31855, 35671) in which treatment had to be re- peated. Nevertheless, the animals reached normal behaviour in about 7 to 8 days after treatment. No severe or debilitating systemic side effects were observed in any of the PGF2alfa-treated bitches, excepting mild symptoms of vomiting and anorexy in one (no. 17863) and sleepiness in three of them (no. 19162, 20529, 24396). There are changes in the genital tract of false pregnant bitches, like increased uterus and hiperplastic endometrium which may be attributed to persistent corpora lutea resulting from continued se- cretion of luteinising hormone from the anterior pituitary or from production of a luteotrophin from another site2. A luteotrophin may be produced by the hyperplastic endometrium of false preg- nancy, and cause the persistence of the corpus luteum. So, the relatively quick disappearance of clinical symptoms of the disease in 37 out of 40 bitches suggests that PGF2alfa could be used for termination of canine false pregnancy through a luteolytic effect, in a similar way as it has been reportedl for termination of unwanted pregnancy in the bitch. Unfortunately, we have no conditions to measure serum levels of LH and progesterone by radioimmunoassay and competitive pro- tein binding techniques in the bitches studied. So, our conditions were limited to breeding and clinical histories, but much more relia- ble observations with regard to clinical examination and good re- sults of the treatment were available. 25\ * Ajinomoto Co., Inc. Tokyo.