EFFECTS OF PROLIGESTONE AND MEGESTROL ON PLASMA ADRENOCORTICOTROPIC HORMONE, INSULIN AND INSULIN-LIKE GROWTH-FACTOR-I CONCENTRATIONS IN CATS

This paper reports changes in adrenocorticotrophic hormone (ACTH), ins ulin and insulinlike growth factor-1 (IGF-1) concentrations in cats fr om a previously published study. The cats mere given oral megestrol ac etate (MA, 5 mg once daily for 14 days), subcutaneous proligestone (PR G, 100 mg on two occasions one meek apart) or subcutaneous saline (1 m l as for PRG). In the cats given saline (n=6), basal ACTH, insulin and IGF-1 did not change significantly throughout the following seven wee ks. The cats given MA (n=7) developed significant suppression of plasm a ACTH concentrations and hyperinsulinaemia during treatment and for t wo to four weeks after MA dosage ceased. In the cats given PRG(n=7), p lasma ACTH concentrations were not significantly altered although thre e cats had markedly suppressed values for some time after PRG treatmen t had ceased. Serum insulin concentrations were not significantly alte red in the PRG-treated cats. The results suggest PRG may be a preferab le alternative to MA in some situations.