Endocrine influences on the detrusor of male and female cats

Abstract

AbstractThe effects of ATP, adenosine (ADS), β,γ‐methylene ATP (APPCP), norepinephrine (NE), and hypogastric nerve stimulation (HGS) on urinary bladder responsiveness have been studied in male and female cats. Recent studies indicated binding sites for estradiol and testosterone in the urinary tract of animals. Other studies have demonstrated that estrogen alters the effects of certain agonists in urinary tract smooth muscle, although the mechanism of this effect is not known. The present study was designed to determine if differences occurred in the response of bladder smooth muscle in male vs. female cats to various stimuli and if surgical or drug pretreatment alters the response.The results of these experiments indicate differences between the response of the urinary bladder in female and male cats to various stimuli and that various pretreatments can alter the detrusor response to selected stimuli. In particular, detrusor of female cats was less responsive to most stimuli than detrusor of male cats, including stimuli that induced inhibition of pelvic‐nerve‐evoked bladder contractions (such as norepinephrine) and stimuli which induced bladder contractions (such as ATP). Also, gonadectomy altered the response of the detrusor making it more responsive to purine inhibitory stimuli, while having a mixed effect on detrusor responsiveness to excitatory stimuli. Pretreatment of cats with a gonadotropin‐releasing hormone antagonist also altered detrusor responsiveness, both inhibitory and excitatory agonists in a variable manner, increasing the magnitude of most responses. In addition to the above‐stated differences, the data also proved to underscore some similarities in the response of male and female cats to adrenergic and cholinergic stimuli. These studies imply that sex hormones influence detrusor response to certain purinergic stimuli and that alteration of sex hormone levels by surgery or medication can impact lower urinary tract function.