title: The effect of maturation and age on oestrogen-induced functional hypertrophy of the female rabbit bladder.
abstract: OBJECTIVE
  To evaluate the effect of maturation and ageing on oestrogen-induced functional hypertrophy of the female rabbit bladder.
  
  
  METHODS
  Twenty female rabbits were separated into two groups of 10 each by age, young (immature) and old rabbits and each age group was subdivided into three subgroups. The rabbits in subgroup 1 were controls, subgroup 2 were ovariectomized (Ovx) and subgroup 3 were Ovx and received 17-beta oestradiol (1 mg/kg/day) by a subcutaneous slow-release tablet implant. After 15 days of treatment, the rabbits were killed, the bladder was excised, and the body and base separated; two full-thickness longitudinal strips from the ventral surface of the bladder body, and one full-thickness strip from the base, were prepared for contractile studies. The contractile responses to electrical-field stimulation, carbachol, ATP and KCl were determined for both the bladder body and base strips. In addition, full-thickness strips of bladder body and base were fixed in formalin for histological and immunohistological studies.
  
  
  RESULTS
  Ovx plus oestradiol resulted in significant increases in bladder weight and responses to all forms of stimulation in young and old rabbits (except for the response to KCl). Vascular density and the smooth muscle (SM)/collagen ratio significantly increased after oestradiol replacement. Interestingly, the increase in vascular density was greater in the young than in the old rabbits.
  
  
  CONCLUSIONS
  The present study shows that oestrogen supplementation mediates a functional hypertrophy characterized by increased contractile responses to all forms of stimulation in both young and old rabbits. The increased contractile responses might be explained by the increases in vascular density and SM/collagen ratio.
authors.affiliation: Albany College of Pharmacy, 106 New Scotland Avenue, Albany, NY 12208, USA.
authors.forename: Bulent
authors.initials: B
authors.lastname: Onal
authors.forename: Robert M
authors.initials: RM
authors.lastname: Levin
authors.forename: Barry A
authors.initials: BA
authors.lastname: Kogan
authors.forename: Catherine
authors.initials: C
authors.lastname: Whitbeck
authors.forename: Paul
authors.initials: P
authors.lastname: Chichester
authors.forename: Oteng
authors.initials: O
authors.lastname: Walebowa
authors.forename: Anita S
authors.initials: AS
authors.lastname: Mannikarottu
mesh_terms: D000375:Aging / Q000187:drug effects* / Q000473:pathology; D000818:Animals; D001835:Body Weight; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D006984:Hypertrophy; D007150:Immunohistochemistry; D009119:Muscle Contraction / Q000187:drug effects* / Q000502:physiology; D009130:Muscle, Smooth / Q000187:drug effects / Q000473:pathology; D010052:Ovariectomy; D011817:Rabbits; D001743:Urinary Bladder / Q000187:drug effects* / Q000473:pathology
chemical_list: D004958:Estradiol